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Subject[PATCH] shm cleanup (2)
Date
Hi all,

Here is my latest patch. It survived ten hours stress testing on my
8way/870MB without oops. (The highmem stuff is too much io/kmap
limited and I will come back to this if we have the mm cleanup ready
:-( )

It apparently has some race condition left since I had some undead
swap entries afterwards. Also the fs accounting was screwed.

I am pretty unsure how shmem_writepage and shmem_nopage can race and
nopage hold the inode semaphore against races against itself and
truncate. Somebody out there to enlighten me?

Greetings
Christoph

diff -uNr 4-12-8/drivers/char/mem.c c/drivers/char/mem.c
--- 4-12-8/drivers/char/mem.c Mon Nov 13 06:55:50 2000
+++ c/drivers/char/mem.c Mon Dec 11 19:42:33 2000
@@ -438,7 +438,7 @@
static int mmap_zero(struct file * file, struct vm_area_struct * vma)
{
if (vma->vm_flags & VM_SHARED)
- return map_zero_setup(vma);
+ return shmem_zero_setup(vma);
if (zeromap_page_range(vma->vm_start, vma->vm_end - vma->vm_start, vma->vm_page_prot))
return -EAGAIN;
return 0;
diff -uNr 4-12-8/include/linux/fs.h c/include/linux/fs.h
--- 4-12-8/include/linux/fs.h Mon Dec 11 19:41:42 2000
+++ c/include/linux/fs.h Wed Dec 13 10:33:04 2000
@@ -283,6 +283,7 @@
#include <linux/efs_fs_i.h>
#include <linux/coda_fs_i.h>
#include <linux/romfs_fs_i.h>
+#include <linux/shmem_fs.h>
#include <linux/smb_fs_i.h>
#include <linux/hfs_fs_i.h>
#include <linux/adfs_fs_i.h>
@@ -354,6 +355,7 @@
struct address_space_operations {
int (*writepage)(struct page *);
int (*readpage)(struct file *, struct page *);
+ struct page * (*getpage)(struct address_space *, unsigned long); /* readpage with alloc */
int (*sync_page)(struct page *);
int (*prepare_write)(struct file *, struct page *, unsigned, unsigned);
int (*commit_write)(struct file *, struct page *, unsigned, unsigned);
@@ -441,6 +443,7 @@
struct ufs_inode_info ufs_i;
struct efs_inode_info efs_i;
struct romfs_inode_info romfs_i;
+ struct shmem_inode_info shmem_i;
struct coda_inode_info coda_i;
struct smb_inode_info smbfs_i;
struct hfs_inode_info hfs_i;
@@ -685,6 +688,7 @@
struct affs_sb_info affs_sb;
struct ufs_sb_info ufs_sb;
struct efs_sb_info efs_sb;
+ struct shmem_sb_info shmem_sb;
struct romfs_sb_info romfs_sb;
struct smb_sb_info smbfs_sb;
struct hfs_sb_info hfs_sb;
diff -uNr 4-12-8/include/linux/mm.h c/include/linux/mm.h
--- 4-12-8/include/linux/mm.h Mon Dec 11 19:41:42 2000
+++ c/include/linux/mm.h Wed Dec 13 10:33:05 2000
@@ -129,15 +129,6 @@
};

/*
- * A swap entry has to fit into a "unsigned long", as
- * the entry is hidden in the "index" field of the
- * swapper address space.
- */
-typedef struct {
- unsigned long val;
-} swp_entry_t;
-
-/*
* Try to keep the most commonly accessed fields in single cache lines
* here (16 bytes or greater). This ordering should be particularly
* beneficial on 32-bit processors.
@@ -390,7 +381,10 @@

extern void clear_page_tables(struct mm_struct *, unsigned long, int);

-extern int map_zero_setup(struct vm_area_struct *);
+int shmem_swapout(struct page * page, struct file *file);
+struct page * shmem_nopage(struct vm_area_struct * vma, unsigned long address, int no_share);
+struct file *shmem_file_setup(char * name, loff_t size);
+extern int shmem_zero_setup(struct vm_area_struct *);

extern void zap_page_range(struct mm_struct *mm, unsigned long address, unsigned long size);
extern int copy_page_range(struct mm_struct *dst, struct mm_struct *src, struct vm_area_struct *vma);
diff -uNr 4-12-8/include/linux/pagemap.h c/include/linux/pagemap.h
--- 4-12-8/include/linux/pagemap.h Mon Dec 4 18:07:05 2000
+++ c/include/linux/pagemap.h Wed Dec 13 10:33:05 2000
@@ -67,6 +67,8 @@

#define page_hash(mapping,index) (page_hash_table+_page_hashfn(mapping,index))

+extern struct page * __find_get_page(struct address_space *mapping,
+ unsigned long offset, struct page **hash);
extern struct page * __find_lock_page (struct address_space * mapping,
unsigned long index, struct page **hash);
extern void lock_page(struct page *page);
diff -uNr 4-12-8/include/linux/shmem_fs.h c/include/linux/shmem_fs.h
--- 4-12-8/include/linux/shmem_fs.h Thu Jan 1 01:00:00 1970
+++ c/include/linux/shmem_fs.h Wed Dec 13 11:04:22 2000
@@ -0,0 +1,37 @@
+#ifndef __SHMEM_FS_H
+#define __SHMEM_FS_H
+
+/* inode in-kernel data */
+
+#define SHMEM_NR_DIRECT 16
+
+/*
+ * A swap entry has to fit into a "unsigned long", as
+ * the entry is hidden in the "index" field of the
+ * swapper address space.
+ */
+typedef struct {
+ unsigned long val;
+} swp_entry_t;
+
+struct shmem_inode_info {
+ swp_entry_t i_direct[SHMEM_NR_DIRECT]; /* for the first blocks */
+ swp_entry_t *i_indirect; /* indirect blocks */
+ swp_entry_t **i_double; /* doubly indirect blocks */
+ struct list_head list;
+ spinlock_t stat_lock; /* This protects the swapped
+ field. We need it since
+ shmem_writepage has to modify it
+ and cannot get inode->i_sem */
+ unsigned long swapped;
+};
+
+struct shmem_sb_info {
+ unsigned long max_blocks; /* How many blocks are allowed */
+ unsigned long free_blocks; /* How many are left for allocation */
+ unsigned long max_inodes; /* How many inodes are allowed */
+ unsigned long free_inodes; /* How many are left for allocation */
+ spinlock_t stat_lock;
+};
+
+#endif
diff -uNr 4-12-8/include/linux/swap.h c/include/linux/swap.h
--- 4-12-8/include/linux/swap.h Mon Dec 11 19:41:43 2000
+++ c/include/linux/swap.h Mon Dec 11 19:44:13 2000
@@ -291,6 +291,8 @@
#define swap_device_lock(p) spin_lock(&p->sdev_lock)
#define swap_device_unlock(p) spin_unlock(&p->sdev_lock)

+extern void shmem_unuse(swp_entry_t entry, struct page *page);
+
#endif /* __KERNEL__*/

#endif /* _LINUX_SWAP_H */
diff -uNr 4-12-8/ipc/shm.c c/ipc/shm.c
--- 4-12-8/ipc/shm.c Mon Dec 11 19:41:43 2000
+++ c/ipc/shm.c Wed Dec 13 10:04:00 2000
@@ -9,23 +9,10 @@
* BIGMEM support, Andrea Arcangeli <andrea@suse.de>
* SMP thread shm, Jean-Luc Boyard <jean-luc.boyard@siemens.fr>
* HIGHMEM support, Ingo Molnar <mingo@redhat.com>
- * avoid vmalloc and make shmmax, shmall, shmmni sysctl'able,
- * Christoph Rohland <hans-christoph.rohland@sap.com>
* Shared /dev/zero support, Kanoj Sarcar <kanoj@sgi.com>
- * make it a file system, Christoph Rohland <hans-christoph.rohland@sap.com>
+ * Move the mm functionality over to mm/shmem.c
+ * Christoph Rohland <cr@sap.com>
*
- * The filesystem has the following restrictions/bugs:
- * 1) It only can handle one directory.
- * 2) Private writeable mappings are not supported
- * 3) Read and write are not implemented (should they?)
- * 4) No special nodes are supported
- *
- * There are the following mount options:
- * - nr_blocks (^= shmall) is the number of blocks of size PAGE_SIZE
- * we are allowed to allocate
- * - nr_inodes (^= shmmni) is the number of files we are allowed to
- * allocate
- * - mode is the mode for the root directory (default S_IRWXUGO | S_ISVTX)
*/

#include <linux/config.h>
@@ -48,65 +35,24 @@

#include "util.h"

-static struct super_block *shm_read_super(struct super_block *,void *, int);
-static void shm_put_super (struct super_block *);
-static int shm_remount_fs (struct super_block *, int *, char *);
-static void shm_read_inode (struct inode *);
-static int shm_statfs (struct super_block *, struct statfs *);
-static int shm_create (struct inode *,struct dentry *,int);
-static struct dentry *shm_lookup (struct inode *,struct dentry *);
-static int shm_unlink (struct inode *,struct dentry *);
-static int shm_setattr (struct dentry *dent, struct iattr *attr);
-static void shm_delete (struct inode *);
-static int shm_mmap (struct file *, struct vm_area_struct *);
-static int shm_readdir (struct file *, void *, filldir_t);
-
-#define SHM_NAME_LEN NAME_MAX
-#define SHM_FMT ".IPC_%08x"
-#define SHM_FMT_LEN 13
-
-/* shm_mode upper byte flags */
-/* SHM_DEST and SHM_LOCKED are used in ipcs(8) */
-#define PRV_DEST 0010000 /* segment will be destroyed on last detach */
-#define PRV_LOCKED 0020000 /* segment will not be swapped */
-#define SHM_UNLK 0040000 /* filename is unlinked */
-#define SHM_SYSV 0100000 /* It is a SYSV shm segment */
-
struct shmid_kernel /* private to the kernel */
{
struct kern_ipc_perm shm_perm;
- size_t shm_segsz;
- unsigned long shm_nattch;
- unsigned long shm_npages; /* size of segment (pages) */
- pte_t **shm_dir; /* ptr to arr of ptrs to frames */
+ struct file * shm_file;
int id;
- union permap {
- struct shmem {
- time_t atime;
- time_t dtime;
- time_t ctime;
- pid_t cpid;
- pid_t lpid;
- int nlen;
- char nm[0];
- } shmem;
- struct zero {
- struct semaphore sema;
- struct list_head list;
- } zero;
- } permap;
+ unsigned long shm_nattch;
+ unsigned long shm_segsz;
+ time_t shm_atim;
+ time_t shm_dtim;
+ time_t shm_ctim;
+ pid_t shm_cprid;
+ pid_t shm_lprid;
};

-#define shm_atim permap.shmem.atime
-#define shm_dtim permap.shmem.dtime
-#define shm_ctim permap.shmem.ctime
-#define shm_cprid permap.shmem.cpid
-#define shm_lprid permap.shmem.lpid
-#define shm_namelen permap.shmem.nlen
-#define shm_name permap.shmem.nm
#define shm_flags shm_perm.mode
-#define zsem permap.zero.sema
-#define zero_list permap.zero.list
+
+static struct file_operations shm_file_operations;
+static struct vm_operations_struct shm_vm_ops;

static struct ipc_ids shm_ids;

@@ -118,207 +64,27 @@
#define shm_buildid(id, seq) \
ipc_buildid(&shm_ids, id, seq)

-static int newseg (key_t key, const char *name, int namelen, int shmflg, size_t size);
-static void seg_free(struct shmid_kernel *shp, int doacc);
+static int newseg (key_t key, int shmflg, size_t size);
static void shm_open (struct vm_area_struct *shmd);
static void shm_close (struct vm_area_struct *shmd);
-static int shm_remove_name(int id);
-static struct page * shm_nopage(struct vm_area_struct *, unsigned long, int);
-static int shm_swapout(struct page *, struct file *);
#ifdef CONFIG_PROC_FS
static int sysvipc_shm_read_proc(char *buffer, char **start, off_t offset, int length, int *eof, void *data);
#endif

-static void zmap_unuse(swp_entry_t entry, struct page *page);
-static void shmzero_open(struct vm_area_struct *shmd);
-static void shmzero_close(struct vm_area_struct *shmd);
-static struct page *shmzero_nopage(struct vm_area_struct * shmd, unsigned long address, int no_share);
-static int zero_id;
-static struct shmid_kernel zshmid_kernel;
-static struct dentry *zdent;
-
-#define SHM_FS_MAGIC 0x02011994
-
-static struct super_block * shm_sb;
-
-static DECLARE_FSTYPE(shm_fs_type, "shm", shm_read_super, FS_SINGLE);
-
-static struct super_operations shm_sops = {
- read_inode: shm_read_inode,
- delete_inode: shm_delete,
- put_super: shm_put_super,
- statfs: shm_statfs,
- remount_fs: shm_remount_fs,
-};
-
-static struct file_operations shm_root_operations = {
- readdir: shm_readdir,
-};
-
-static struct inode_operations shm_root_inode_operations = {
- create: shm_create,
- lookup: shm_lookup,
- unlink: shm_unlink,
-};
-
-static struct file_operations shm_file_operations = {
- mmap: shm_mmap,
-};
-
-static struct inode_operations shm_inode_operations = {
- setattr: shm_setattr,
-};
-
-static struct vm_operations_struct shm_vm_ops = {
- open: shm_open, /* callback for a new vm-area open */
- close: shm_close, /* callback for when the vm-area is released */
- nopage: shm_nopage,
- swapout:shm_swapout,
-};
-
-size_t shm_ctlmax = SHMMAX;
-
-/* These parameters should be part of the superblock */
-static int shm_ctlall;
-static int shm_ctlmni;
-static int shm_mode;
+size_t shm_ctlmax = SHMMAX;
+size_t shm_ctlall = SHMALL;
+int shm_ctlmni = SHMMNI;

static int shm_tot; /* total number of shared memory pages */
-static int shm_rss; /* number of shared memory pages that are in memory */
-static int shm_swp; /* number of shared memory pages that are in swap */
-
-/* locks order:
- pagecache_lock
- shm_lock()/shm_lockall()
- kernel lock
- inode->i_sem
- sem_ids.sem
- mmap_sem
-
- SMP assumptions:
- - swap_free() never sleeps
- - add_to_swap_cache() never sleeps
- - add_to_swap_cache() doesn't acquire the big kernel lock.
- - shm_unuse() is called with the kernel lock acquired.
- */
-
-/* some statistics */
-static ulong swap_attempts;
-static ulong swap_successes;

void __init shm_init (void)
{
- struct vfsmount *res;
ipc_init_ids(&shm_ids, 1);
-
- register_filesystem (&shm_fs_type);
- res = kern_mount(&shm_fs_type);
- if (IS_ERR(res)) {
- unregister_filesystem(&shm_fs_type);
- return;
- }
-#ifdef CONFIG_PROC_FS
create_proc_read_entry("sysvipc/shm", 0, 0, sysvipc_shm_read_proc, NULL);
-#endif
- zero_id = ipc_addid(&shm_ids, &zshmid_kernel.shm_perm, 1);
- shm_unlock(zero_id);
- INIT_LIST_HEAD(&zshmid_kernel.zero_list);
- zdent = d_alloc_root(get_empty_inode());
- return;
-}
-
-static int shm_parse_options(char *options)
-{
- int blocks = shm_ctlall;
- int inodes = shm_ctlmni;
- umode_t mode = shm_mode;
- char *this_char, *value;
-
- this_char = NULL;
- if ( options )
- this_char = strtok(options,",");
- for ( ; this_char; this_char = strtok(NULL,",")) {
- if ((value = strchr(this_char,'=')) != NULL)
- *value++ = 0;
- if (!strcmp(this_char,"nr_blocks")) {
- if (!value || !*value)
- return 1;
- blocks = simple_strtoul(value,&value,0);
- if (*value)
- return 1;
- }
- else if (!strcmp(this_char,"nr_inodes")) {
- if (!value || !*value)
- return 1;
- inodes = simple_strtoul(value,&value,0);
- if (*value)
- return 1;
- }
- else if (!strcmp(this_char,"mode")) {
- if (!value || !*value)
- return 1;
- mode = simple_strtoul(value,&value,8);
- if (*value)
- return 1;
- }
- else
- return 1;
- }
- shm_ctlmni = inodes;
- shm_ctlall = blocks;
- shm_mode = mode;
-
- return 0;
-}
-
-static struct super_block *shm_read_super(struct super_block *s,void *data,
- int silent)
-{
- struct inode * root_inode;
-
- shm_ctlall = SHMALL;
- shm_ctlmni = SHMMNI;
- shm_mode = S_IRWXUGO | S_ISVTX;
- if (shm_parse_options (data)) {
- printk(KERN_ERR "shm fs invalid option\n");
- goto out_unlock;
- }
-
- s->s_blocksize = PAGE_SIZE;
- s->s_blocksize_bits = PAGE_SHIFT;
- s->s_magic = SHM_FS_MAGIC;
- s->s_op = &shm_sops;
- root_inode = iget (s, SEQ_MULTIPLIER);
- if (!root_inode)
- goto out_no_root;
- root_inode->i_op = &shm_root_inode_operations;
- root_inode->i_sb = s;
- root_inode->i_nlink = 2;
- root_inode->i_mode = S_IFDIR | shm_mode;
- s->s_root = d_alloc_root(root_inode);
- if (!s->s_root)
- goto out_no_root;
- shm_sb = s;
- return s;
-
-out_no_root:
- printk(KERN_ERR "shm_read_super: get root inode failed\n");
- iput(root_inode);
-out_unlock:
- return NULL;
-}
-
-static int shm_remount_fs (struct super_block *sb, int *flags, char *data)
-{
- if (shm_parse_options (data))
- return -EINVAL;
- return 0;
}

static inline int shm_checkid(struct shmid_kernel *s, int id)
{
- if (!(s->shm_flags & SHM_SYSV))
- return -EINVAL;
if (ipc_checkid(&shm_ids,&s->shm_perm,id))
return -EIDRM;
return 0;
@@ -334,460 +100,137 @@
return ipc_addid(&shm_ids, &shp->shm_perm, shm_ctlmni+1);
}

-static void shm_put_super(struct super_block *sb)
-{
- int i;
- struct shmid_kernel *shp;
-
- down(&shm_ids.sem);
- for(i = 0; i <= shm_ids.max_id; i++) {
- if (i == zero_id)
- continue;
- if (!(shp = shm_lock (i)))
- continue;
- if (shp->shm_nattch)
- printk(KERN_DEBUG "shm_nattch = %ld\n", shp->shm_nattch);
- shp = shm_rmid(i);
- shm_unlock(i);
- seg_free(shp, 1);
- }
- dput (sb->s_root);
- up(&shm_ids.sem);
-}
-
-static int shm_statfs(struct super_block *sb, struct statfs *buf)
-{
- buf->f_type = SHM_FS_MAGIC;
- buf->f_bsize = PAGE_SIZE;
- buf->f_blocks = shm_ctlall;
- buf->f_bavail = buf->f_bfree = shm_ctlall - shm_tot;
- buf->f_files = shm_ctlmni;
- shm_lockall();
- buf->f_ffree = shm_ctlmni - shm_ids.in_use + 1;
- shm_unlockall();
- buf->f_namelen = SHM_NAME_LEN;
- return 0;
-}
-
-static void shm_read_inode(struct inode * inode)
-{
- int id;
- struct shmid_kernel *shp;
-
- id = inode->i_ino;
- inode->i_mode = 0;
- inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
-
- if (id < SEQ_MULTIPLIER) {
- if (!(shp = shm_lock (id))) {
- make_bad_inode(inode);
- return;
- }
- inode->i_mode = (shp->shm_flags & S_IALLUGO) | S_IFREG;
- inode->i_uid = shp->shm_perm.uid;
- inode->i_gid = shp->shm_perm.gid;
- inode->i_size = shp->shm_segsz;
- shm_unlock (id);
- inode->i_op = &shm_inode_operations;
- inode->i_fop = &shm_file_operations;
- return;
- }
- inode->i_op = &shm_root_inode_operations;
- inode->i_fop = &shm_root_operations;
- inode->i_sb = shm_sb;
- inode->i_nlink = 2;
- inode->i_mode = S_IFDIR | shm_mode;
- inode->i_uid = inode->i_gid = 0;
-
-}
-
-static int shm_create (struct inode *dir, struct dentry *dent, int mode)
-{
- int id, err;
- struct inode * inode;
-
- down(&shm_ids.sem);
- err = id = newseg (IPC_PRIVATE, dent->d_name.name, dent->d_name.len, mode, 0);
- if (err < 0)
- goto out;
-
- err = -ENOMEM;
- inode = iget (shm_sb, id % SEQ_MULTIPLIER);
- if (!inode)
- goto out;

- err = 0;
- down (&inode->i_sem);
- inode->i_mode = mode | S_IFREG;
- inode->i_op = &shm_inode_operations;
- d_instantiate(dent, inode);
- up (&inode->i_sem);
-
-out:
- up(&shm_ids.sem);
- return err;
-}

-static int shm_readdir (struct file *filp, void *dirent, filldir_t filldir)
-{
- struct inode * inode = filp->f_dentry->d_inode;
+static inline void shm_inc (int id) {
struct shmid_kernel *shp;
- off_t nr;
-
- nr = filp->f_pos;
-
- switch(nr)
- {
- case 0:
- if (filldir(dirent, ".", 1, nr, inode->i_ino, DT_DIR) < 0)
- return 0;
- filp->f_pos = ++nr;
- /* fall through */
- case 1:
- if (filldir(dirent, "..", 2, nr, inode->i_ino, DT_DIR) < 0)
- return 0;
- filp->f_pos = ++nr;
- /* fall through */
- default:
- down(&shm_ids.sem);
- for (; nr-2 <= shm_ids.max_id; nr++ ) {
- if (nr-2 == zero_id)
- continue;
- if (!(shp = shm_get (nr-2)))
- continue;
- if (shp->shm_flags & SHM_UNLK)
- continue;
- if (filldir(dirent, shp->shm_name, shp->shm_namelen, nr, nr, DT_REG) < 0 )
- break;;
- }
- filp->f_pos = nr;
- up(&shm_ids.sem);
- break;
- }
-
- UPDATE_ATIME(inode);
- return 0;
-}
-
-static struct dentry *shm_lookup (struct inode *dir, struct dentry *dent)
-{
- int i, err = 0;
- struct shmid_kernel* shp;
- struct inode *inode = NULL;
-
- if (dent->d_name.len > SHM_NAME_LEN)
- return ERR_PTR(-ENAMETOOLONG);
-
- down(&shm_ids.sem);
- for(i = 0; i <= shm_ids.max_id; i++) {
- if (i == zero_id)
- continue;
- if (!(shp = shm_lock(i)))
- continue;
- if (!(shp->shm_flags & SHM_UNLK) &&
- dent->d_name.len == shp->shm_namelen &&
- strncmp(dent->d_name.name, shp->shm_name, shp->shm_namelen) == 0)
- goto found;
- shm_unlock(i);
- }

- /*
- * prevent the reserved names as negative dentries.
- * This also prevents object creation through the filesystem
- */
- if (dent->d_name.len == SHM_FMT_LEN &&
- memcmp (SHM_FMT, dent->d_name.name, SHM_FMT_LEN - 8) == 0)
- err = -EINVAL; /* EINVAL to give IPC_RMID the right error */
-
- goto out;
-
-found:
- shm_unlock(i);
- inode = iget(dir->i_sb, i);
-
- if (!inode)
- err = -EACCES;
-out:
- if (err == 0)
- d_add (dent, inode);
- up (&shm_ids.sem);
- return ERR_PTR(err);
+ if(!(shp = shm_lock(id)))
+ BUG();
+ shp->shm_atim = CURRENT_TIME;
+ shp->shm_lprid = current->pid;
+ shm_unlock(id);
}

-static int shm_unlink (struct inode *dir, struct dentry *dent)
+/* This is called by fork, once for every shm attach. */
+static void shm_open (struct vm_area_struct *shmd)
{
- struct inode * inode = dent->d_inode;
- struct shmid_kernel *shp;
-
- down (&shm_ids.sem);
- if (!(shp = shm_lock (inode->i_ino)))
- BUG();
- shp->shm_flags |= SHM_UNLK | PRV_DEST;
- shp->shm_perm.key = IPC_PRIVATE; /* Do not find it any more */
- shm_unlock (inode->i_ino);
- up (&shm_ids.sem);
- inode->i_nlink -= 1;
- /*
- * If it's a reserved name we have to drop the dentry instead
- * of creating a negative dentry
- */
- if (dent->d_name.len == SHM_FMT_LEN &&
- memcmp (SHM_FMT, dent->d_name.name, SHM_FMT_LEN - 8) == 0)
- d_drop (dent);
- return 0;
+ shm_inc (shmd->vm_file->f_dentry->d_inode->i_ino);
}

/*
- * We cannot use kmalloc for shm_alloc since this restricts the
- * maximum size of the segments.
- *
- * We also cannot use vmalloc, since this uses too much of the vmalloc
- * space and we run out of this on highend machines.
+ * shm_destroy - free the struct shmid_kernel
*
- * So we have to use this complicated indirect scheme to alloc the shm
- * page tables.
+ * @shp: struct to free
*
+ * It has to be called with shp and shm_ids.sem locked and will
+ * release them
*/
-
-#ifdef PTE_INIT
-static inline void init_ptes (pte_t *pte, int number) {
- while (number--)
- PTE_INIT (pte++);
-}
-#else
-static inline void init_ptes (pte_t *pte, int number) {
- memset (pte, 0, number*sizeof(*pte));
-}
-#endif
-
-#define PTES_PER_PAGE (PAGE_SIZE/sizeof(pte_t))
-#define SHM_ENTRY(shp, index) (shp)->shm_dir[(index)/PTES_PER_PAGE][(index)%PTES_PER_PAGE]
-
-static pte_t **shm_alloc(unsigned long pages, int doacc)
-{
- unsigned short dir = pages / PTES_PER_PAGE;
- unsigned short last = pages % PTES_PER_PAGE;
- pte_t **ret, **ptr;
-
- if (pages == 0)
- return NULL;
-
- ret = kmalloc ((dir+1) * sizeof(pte_t *), GFP_USER);
- if (!ret)
- goto nomem;
-
- for (ptr = ret; ptr < ret+dir ; ptr++)
- {
- *ptr = (pte_t *)__get_free_page (GFP_USER);
- if (!*ptr)
- goto free;
- init_ptes (*ptr, PTES_PER_PAGE);
- }
-
- /* The last one is probably not of PAGE_SIZE: we use kmalloc */
- if (last) {
- *ptr = kmalloc (last*sizeof(pte_t), GFP_USER);
- if (!*ptr)
- goto free;
- init_ptes (*ptr, last);
- }
- if (doacc) {
- shm_lockall();
- shm_tot += pages;
- shm_unlockall();
- }
- return ret;
-
-free:
- /* The last failed: we decrement first */
- while (--ptr >= ret)
- free_page ((unsigned long)*ptr);
-
- kfree (ret);
-nomem:
- return ERR_PTR(-ENOMEM);
-}
-
-static void shm_free(pte_t** dir, unsigned long pages, int doacc)
+static void shm_destroy (struct shmid_kernel *shp)
{
- int i, rss, swp;
- pte_t **ptr = dir+pages/PTES_PER_PAGE;
-
- if (!dir)
- return;
-
- for (i = 0, rss = 0, swp = 0; i < pages ; i++) {
- pte_t pte;
- pte = dir[i/PTES_PER_PAGE][i%PTES_PER_PAGE];
- if (pte_none(pte))
- continue;
- if (pte_present(pte)) {
- __free_page (pte_page(pte));
- rss++;
- } else {
- swap_free(pte_to_swp_entry(pte));
- swp++;
- }
- }
-
- /* first the last page */
- if (pages%PTES_PER_PAGE)
- kfree (*ptr);
- /* now the whole pages */
- while (--ptr >= dir)
- if (*ptr)
- free_page ((unsigned long)*ptr);
-
- /* Now the indirect block */
- kfree (dir);
+ struct file * file = shp->shm_file;

- if (doacc) {
- shm_lockall();
- shm_rss -= rss;
- shm_swp -= swp;
- shm_tot -= pages;
- shm_unlockall();
- }
+ shp->shm_file = NULL;
+ shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ shm_unlock (shp->id);
+ shm_rmid (shp->id);
+ kfree (shp);
+ up (&shm_ids.sem);
+ /* put the file outside the critical path to prevent recursion */
+ fput (file);
}

-static int shm_setattr (struct dentry *dentry, struct iattr *attr)
+/*
+ * remove the attach descriptor shmd.
+ * free memory for segment if it is marked destroyed.
+ * The descriptor has already been removed from the current->mm->mmap list
+ * and will later be kfree()d.
+ */
+static void shm_close (struct vm_area_struct *shmd)
{
- int error;
- struct inode *inode = dentry->d_inode;
+ struct file * file = shmd->vm_file;
+ int id = file->f_dentry->d_inode->i_ino;
struct shmid_kernel *shp;
- unsigned long new_pages, old_pages;
- pte_t **new_dir, **old_dir;
-
- error = inode_change_ok(inode, attr);
- if (error)
- return error;
- if (!(attr->ia_valid & ATTR_SIZE))
- goto set_attr;
- if (attr->ia_size > shm_ctlmax)
- return -EFBIG;
-
- /* We set old_pages and old_dir for easier cleanup */
- old_pages = new_pages = (attr->ia_size + PAGE_SIZE - 1) >> PAGE_SHIFT;
- old_dir = new_dir = shm_alloc(new_pages, 1);
- if (IS_ERR(new_dir))
- return PTR_ERR(new_dir);

- if (!(shp = shm_lock(inode->i_ino)))
- BUG();
- error = -ENOSPC;
- if (shm_tot - shp->shm_npages >= shm_ctlall)
- goto size_out;
- error = 0;
- if (shp->shm_segsz == attr->ia_size)
- goto size_out;
- /* Now we set them to the real values */
- old_dir = shp->shm_dir;
- old_pages = shp->shm_npages;
- if (old_dir){
- pte_t *swap;
- int i,j;
- i = old_pages < new_pages ? old_pages : new_pages;
- j = i % PTES_PER_PAGE;
- i /= PTES_PER_PAGE;
- if (j)
- memcpy (new_dir[i], old_dir[i], j * sizeof (pte_t));
- while (i--) {
- swap = new_dir[i];
- new_dir[i] = old_dir[i];
- old_dir[i] = swap;
- }
- }
- shp->shm_dir = new_dir;
- shp->shm_npages = new_pages;
- shp->shm_segsz = attr->ia_size;
-size_out:
- shm_unlock(inode->i_ino);
- shm_free (old_dir, old_pages, 1);
-
-set_attr:
- if (!(shp = shm_lock(inode->i_ino)))
+ down (&shm_ids.sem);
+ /* remove from the list of attaches of the shm segment */
+ if(!(shp = shm_lock(id)))
BUG();
- if (attr->ia_valid & ATTR_MODE)
- shp->shm_perm.mode = attr->ia_mode;
- if (attr->ia_valid & ATTR_UID)
- shp->shm_perm.uid = attr->ia_uid;
- if (attr->ia_valid & ATTR_GID)
- shp->shm_perm.gid = attr->ia_gid;
- shm_unlock (inode->i_ino);
+ shp->shm_lprid = current->pid;
+ shp->shm_dtim = CURRENT_TIME;
+ if(shp->shm_flags & SHM_DEST &&
+ file_count (file) == 2) /* shp and the vma have the last
+ references*/
+ return shm_destroy (shp);

- inode_setattr(inode, attr);
- return error;
+ shm_unlock(id);
+ up (&shm_ids.sem);
}

-static struct shmid_kernel *seg_alloc(int numpages, size_t namelen)
+static int shm_mmap(struct file * file, struct vm_area_struct * vma)
{
- struct shmid_kernel *shp;
- pte_t **dir;
-
- shp = (struct shmid_kernel *) kmalloc (sizeof (*shp) + namelen, GFP_USER);
- if (!shp)
- return ERR_PTR(-ENOMEM);
-
- dir = shm_alloc (numpages, namelen);
- if (IS_ERR(dir)) {
- kfree(shp);
- return ERR_PTR(PTR_ERR(dir));
- }
- shp->shm_dir = dir;
- shp->shm_npages = numpages;
- shp->shm_nattch = 0;
- shp->shm_namelen = namelen;
- return(shp);
+ UPDATE_ATIME(file->f_dentry->d_inode);
+ vma->vm_ops = &shm_vm_ops;
+ shm_inc(file->f_dentry->d_inode->i_ino);
+ return 0;
}

-static void seg_free(struct shmid_kernel *shp, int doacc)
-{
- shm_free (shp->shm_dir, shp->shm_npages, doacc);
- kfree(shp);
-}
+static struct file_operations shm_file_operations = {
+ mmap: shm_mmap
+};

-static int newseg (key_t key, const char *name, int namelen,
- int shmflg, size_t size)
+static struct vm_operations_struct shm_vm_ops = {
+ open: shm_open, /* callback for a new vm-area open */
+ close: shm_close, /* callback for when the vm-area is released */
+ nopage: shmem_nopage,
+ swapout:shmem_swapout,
+};
+
+static int newseg (key_t key, int shmflg, size_t size)
{
+ int error;
struct shmid_kernel *shp;
int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
+ struct file * file;
+ char name[13];
int id;

- if (namelen > SHM_NAME_LEN)
- return -ENAMETOOLONG;
-
- if (size > shm_ctlmax)
- return -EINVAL;
-
if (shm_tot + numpages >= shm_ctlall)
return -ENOSPC;

- shp = seg_alloc(numpages, namelen ? namelen : SHM_FMT_LEN + 1);
- if (IS_ERR(shp))
- return PTR_ERR(shp);
+ shp = (struct shmid_kernel *) kmalloc (sizeof (*shp), GFP_USER);
+ if (!shp)
+ return -ENOMEM;
+ sprintf (name, "SYSV%08x", key);
+ file = shmem_file_setup(name, size);
+ error = PTR_ERR(file);
+ if (IS_ERR(file))
+ goto no_file;
+
+ error = -ENOSPC;
id = shm_addid(shp);
- if(id == -1) {
- seg_free(shp, 1);
- return -ENOSPC;
- }
+ if(id == -1)
+ goto no_id;
shp->shm_perm.key = key;
shp->shm_flags = (shmflg & S_IRWXUGO);
- shp->shm_segsz = size;
shp->shm_cprid = current->pid;
shp->shm_lprid = 0;
shp->shm_atim = shp->shm_dtim = 0;
shp->shm_ctim = CURRENT_TIME;
+ shp->shm_segsz = size;
shp->id = shm_buildid(id,shp->shm_perm.seq);
- if (namelen != 0) {
- shp->shm_namelen = namelen;
- memcpy (shp->shm_name, name, namelen);
- } else {
- shp->shm_flags |= SHM_SYSV;
- shp->shm_namelen = sprintf (shp->shm_name, SHM_FMT, shp->id);
- }
- shm_unlock(id);
-
+ shp->shm_file = file;
+ file->f_dentry->d_inode->i_ino = id;
+ file->f_op = &shm_file_operations;
+ shm_tot += numpages;
+ shm_unlock (id);
return shp->id;
+
+no_id:
+ fput(file);
+no_file:
+ kfree(shp);
+ return error;
}

asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
@@ -795,17 +238,17 @@
struct shmid_kernel *shp;
int err, id = 0;

- if (size < SHMMIN)
+ if (size < SHMMIN || size > shm_ctlmax)
return -EINVAL;

down(&shm_ids.sem);
if (key == IPC_PRIVATE) {
- err = newseg(key, NULL, 0, shmflg, size);
- } else if ((id = ipc_findkey(&shm_ids,key)) == -1) {
+ err = newseg(key, shmflg, size);
+ } else if ((id = ipc_findkey(&shm_ids, key)) == -1) {
if (!(shmflg & IPC_CREAT))
err = -ENOENT;
else
- err = newseg(key, NULL, 0, shmflg, size);
+ err = newseg(key, shmflg, size);
} else if ((shmflg & IPC_CREAT) && (shmflg & IPC_EXCL)) {
err = -EEXIST;
} else {
@@ -824,24 +267,6 @@
return err;
}

-/* FIXME: maybe we need lock_kernel() here */
-static void shm_delete (struct inode *ino)
-{
- int shmid = ino->i_ino;
- struct shmid_kernel *shp;
-
- down(&shm_ids.sem);
- shp = shm_lock(shmid);
- if(shp==NULL) {
- BUG();
- }
- shp = shm_rmid(shmid);
- shm_unlock(shmid);
- up(&shm_ids.sem);
- seg_free(shp, 1);
- clear_inode(ino);
-}
-
static inline unsigned long copy_shmid_to_user(void *buf, struct shmid64_ds *in, int version)
{
switch(version) {
@@ -933,6 +358,30 @@
}
}

+static void shm_get_stat (unsigned long *rss, unsigned long *swp)
+{
+ int i;
+
+ *rss = 0;
+ *swp = 0;
+
+ for(i = 0; i <= shm_ids.max_id; i++) {
+ struct shmid_kernel* shp;
+ struct inode * inode;
+
+ shp = shm_get(i);
+ if(shp == NULL || shp->shm_file == NULL)
+ continue;
+ inode = shp->shm_file->f_dentry->d_inode;
+ down (&inode->i_sem);
+ *rss += inode->i_mapping->nrpages;
+ spin_lock (&inode->u.shmem_i.stat_lock);
+ *swp += inode->u.shmem_i.swapped;
+ spin_unlock (&inode->u.shmem_i.stat_lock);
+ up (&inode->i_sem);
+ }
+}
+
asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds *buf)
{
struct shm_setbuf setbuf;
@@ -968,15 +417,16 @@
struct shm_info shm_info;

memset(&shm_info,0,sizeof(shm_info));
+ down(&shm_ids.sem);
shm_lockall();
- shm_info.used_ids = shm_ids.in_use - 1; /* correct the /dev/zero hack */
- shm_info.shm_rss = shm_rss;
+ shm_info.used_ids = shm_ids.in_use;
+ shm_get_stat (&shm_info.shm_rss, &shm_info.shm_swp);
shm_info.shm_tot = shm_tot;
- shm_info.shm_swp = shm_swp;
- shm_info.swap_attempts = swap_attempts;
- shm_info.swap_successes = swap_successes;
+ shm_info.swap_attempts = 0;
+ shm_info.swap_successes = 0;
err = shm_ids.max_id;
shm_unlockall();
+ up(&shm_ids.sem);
if(copy_to_user (buf, &shm_info, sizeof(shm_info)))
return -EFAULT;

@@ -987,16 +437,13 @@
{
struct shmid64_ds tbuf;
int result;
- if ((shmid % SEQ_MULTIPLIER) == zero_id)
- return -EINVAL;
memset(&tbuf, 0, sizeof(tbuf));
shp = shm_lock(shmid);
if(shp==NULL)
return -EINVAL;
if(cmd==SHM_STAT) {
err = -EINVAL;
- if (!(shp->shm_flags & SHM_SYSV) ||
- shmid > shm_ids.max_id)
+ if (shmid > shm_ids.max_id)
goto out_unlock;
result = shm_buildid(shmid, shp->shm_perm.seq);
} else {
@@ -1009,20 +456,13 @@
if (ipcperms (&shp->shm_perm, S_IRUGO))
goto out_unlock;
kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
- /* ugly hack to keep binary compatibility for ipcs */
- tbuf.shm_flags &= PRV_DEST | PRV_LOCKED | S_IRWXUGO;
- if (tbuf.shm_flags & PRV_DEST)
- tbuf.shm_flags |= SHM_DEST;
- if (tbuf.shm_flags & PRV_LOCKED)
- tbuf.shm_flags |= SHM_LOCKED;
- tbuf.shm_flags &= SHM_DEST | SHM_LOCKED | S_IRWXUGO;
tbuf.shm_segsz = shp->shm_segsz;
tbuf.shm_atime = shp->shm_atim;
tbuf.shm_dtime = shp->shm_dtim;
tbuf.shm_ctime = shp->shm_ctim;
tbuf.shm_cpid = shp->shm_cprid;
tbuf.shm_lpid = shp->shm_lprid;
- tbuf.shm_nattch = shp->shm_nattch;
+ tbuf.shm_nattch = file_count (shp->shm_file) - 1;
shm_unlock(shmid);
if(copy_shmid_to_user (buf, &tbuf, version))
return -EFAULT;
@@ -1034,8 +474,6 @@
/* Allow superuser to lock segment in memory */
/* Should the pages be faulted in here or leave it to user? */
/* need to determine interaction with current->swappable */
- if ((shmid % SEQ_MULTIPLIER)== zero_id)
- return -EINVAL;
if (!capable(CAP_IPC_LOCK))
return -EPERM;

@@ -1045,10 +483,13 @@
err = shm_checkid(shp,shmid);
if(err)
goto out_unlock;
- if(cmd==SHM_LOCK)
- shp->shm_flags |= PRV_LOCKED;
- else
- shp->shm_flags &= ~PRV_LOCKED;
+ if(cmd==SHM_LOCK) {
+ shp->shm_file->private_data = (void*) -1;
+ shp->shm_flags |= SHM_LOCKED;
+ } else {
+ shp->shm_file->private_data = 0;
+ shp->shm_flags &= ~SHM_LOCKED;
+ }
shm_unlock(shmid);
return err;
}
@@ -1064,29 +505,18 @@
* Instead we set a destroyed flag, and then blow
* the name away when the usage hits zero.
*/
- if ((shmid % SEQ_MULTIPLIER) == zero_id)
- return -EINVAL;
down(&shm_ids.sem);
shp = shm_lock(shmid);
- if (shp == NULL) {
- up(&shm_ids.sem);
- return -EINVAL;
- }
+ err = -EINVAL;
+ if (shp == NULL)
+ goto out_up;
err = shm_checkid(shp, shmid);
if (err == 0) {
- if (shp->shm_nattch == 0 &&
- !(shp->shm_flags & SHM_UNLK)) {
- int id=shp->id;
- shm_unlock(shmid);
- up(&shm_ids.sem);
- /*
- * We can't hold shm_lock here else we
- * will deadlock in shm_lookup when we
- * try to recursively grab it.
- */
- return shm_remove_name(id);
+ if (file_count (shp->shm_file) == 1) {
+ shm_destroy (shp);
+ return 0;
}
- shp->shm_flags |= PRV_DEST;
+ shp->shm_flags |= SHM_DEST;
/* Do not find it any more */
shp->shm_perm.key = IPC_PRIVATE;
}
@@ -1098,12 +528,6 @@

case IPC_SET:
{
- struct dentry * dentry;
- char name[SHM_FMT_LEN+1];
-
- if ((shmid % SEQ_MULTIPLIER)== zero_id)
- return -EINVAL;
-
if(copy_shmid_from_user (&setbuf, buf, version))
return -EFAULT;
down(&shm_ids.sem);
@@ -1126,27 +550,7 @@
shp->shm_flags = (shp->shm_flags & ~S_IRWXUGO)
| (setbuf.mode & S_IRWXUGO);
shp->shm_ctim = CURRENT_TIME;
- shm_unlock(shmid);
- up(&shm_ids.sem);
-
- sprintf (name, SHM_FMT, shmid);
- dentry = lookup_one(name, lock_parent(shm_sb->s_root));
- unlock_dir(shm_sb->s_root);
- err = PTR_ERR(dentry);
- if (IS_ERR(dentry))
- goto bad_dentry;
- err = -ENOENT;
- if (dentry->d_inode) {
- struct inode *ino = dentry->d_inode;
- ino->i_uid = setbuf.uid;
- ino->i_gid = setbuf.gid;
- ino->i_mode = (setbuf.mode & S_IRWXUGO) | (ino->i_mode & ~S_IALLUGO);;
- ino->i_atime = ino->i_mtime = ino->i_ctime = CURRENT_TIME;
- err = 0;
- }
- dput (dentry);
- bad_dentry:
- return err;
+ break;
}

default:
@@ -1164,27 +568,6 @@
return err;
}

-static inline void shm_inc (int id) {
- struct shmid_kernel *shp;
-
- if(!(shp = shm_lock(id)))
- BUG();
- shp->shm_atim = CURRENT_TIME;
- shp->shm_lprid = current->pid;
- shp->shm_nattch++;
- shm_unlock(id);
-}
-
-static int shm_mmap(struct file * file, struct vm_area_struct * vma)
-{
- if ((vma->vm_flags & VM_WRITE) && !(vma->vm_flags & VM_SHARED))
- return -EINVAL; /* we cannot do private writable mappings */
- UPDATE_ATIME(file->f_dentry->d_inode);
- vma->vm_ops = &shm_vm_ops;
- shm_inc(file->f_dentry->d_inode->i_ino);
- return 0;
-}
-
/*
* Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
*/
@@ -1198,11 +581,9 @@
unsigned long prot;
unsigned long o_flags;
int acc_mode;
- struct dentry *dentry;
- char name[SHM_FMT_LEN+1];
void *user_addr;

- if (!shm_sb || shmid < 0 || (shmid % SEQ_MULTIPLIER) == zero_id)
+ if (shmid < 0)
return -EINVAL;

if ((addr = (ulong)shmaddr)) {
@@ -1231,123 +612,26 @@
* aditional creator id...
*/
shp = shm_lock(shmid);
- if(shp==NULL)
+ if(shp == NULL)
return -EINVAL;
- err = ipcperms(&shp->shm_perm, acc_mode);
- shm_unlock(shmid);
- if (err)
+ if (ipcperms(&shp->shm_perm, acc_mode)) {
+ shm_unlock(shmid);
return -EACCES;
+ }
+ file = shp->shm_file;
+ get_file (file);
+ shm_unlock(shmid);

- sprintf (name, SHM_FMT, shmid);
-
- mntget(shm_fs_type.kern_mnt);
- dentry = lookup_one(name, lock_parent(shm_sb->s_root));
- unlock_dir(shm_sb->s_root);
- err = PTR_ERR(dentry);
- if (IS_ERR(dentry))
- goto bad_file;
- err = -ENOENT;
- if (!dentry->d_inode)
- goto bad_file;
- file = dentry_open(dentry, shm_fs_type.kern_mnt, o_flags);
- err = PTR_ERR(file);
- if (IS_ERR (file))
- goto bad_file1;
down(&current->mm->mmap_sem);
user_addr = (void *) do_mmap (file, addr, file->f_dentry->d_inode->i_size, prot, flags, 0);
up(&current->mm->mmap_sem);
+ fput (file);
*raddr = (unsigned long) user_addr;
err = 0;
if (IS_ERR(user_addr))
err = PTR_ERR(user_addr);
- fput (file);
- return err;
-
-bad_file1:
- dput(dentry);
-bad_file:
- mntput(shm_fs_type.kern_mnt);
- if (err == -ENOENT)
- return -EINVAL;
return err;
-}
-
-/* This is called by fork, once for every shm attach. */
-static void shm_open (struct vm_area_struct *shmd)
-{
- shm_inc (shmd->vm_file->f_dentry->d_inode->i_ino);
-}
-
-/*
- * Remove a name.
- */
-
-static int shm_remove_name(int id)
-{
- struct dentry *dir;
- struct dentry *dentry;
- int error;
- char name[SHM_FMT_LEN+1];

- sprintf (name, SHM_FMT, id);
- dir = lock_parent(shm_sb->s_root);
- dentry = lookup_one(name, dir);
- error = PTR_ERR(dentry);
- if (!IS_ERR(dentry)) {
- /*
- * We have to do our own unlink to prevent the vfs
- * permission check. The SYSV IPC layer has already
- * checked the permissions which do not comply to the
- * vfs rules.
- */
- struct inode *inode = dir->d_inode;
- down(&inode->i_zombie);
- error = shm_unlink(inode, dentry);
- if (!error)
- d_delete(dentry);
- up(&inode->i_zombie);
- dput(dentry);
- }
- unlock_dir(dir);
- return error;
-}
-
-/*
- * remove the attach descriptor shmd.
- * free memory for segment if it is marked destroyed.
- * The descriptor has already been removed from the current->mm->mmap list
- * and will later be kfree()d.
- */
-static void shm_close (struct vm_area_struct *shmd)
-{
- int id = shmd->vm_file->f_dentry->d_inode->i_ino;
- struct shmid_kernel *shp;
-
- /* remove from the list of attaches of the shm segment */
- if(!(shp = shm_lock(id)))
- BUG();
- shp->shm_lprid = current->pid;
- shp->shm_dtim = CURRENT_TIME;
- shp->shm_nattch--;
- if(shp->shm_nattch == 0 &&
- shp->shm_flags & PRV_DEST &&
- !(shp->shm_flags & SHM_UNLK)) {
- int pid=shp->id;
- int err;
- shm_unlock(id);
-
- /* The kernel lock prevents new attaches from
- * being happening. We can't hold shm_lock here
- * else we will deadlock in shm_lookup when we
- * try to recursively grab it.
- */
- err = shm_remove_name(pid);
- if(err && err != -EINVAL && err != -ENOENT)
- printk(KERN_ERR "Unlink of SHM id %d failed (%d).\n", pid, err);
-
- } else {
- shm_unlock(id);
- }
}

/*
@@ -1370,189 +654,6 @@
return 0;
}

-/*
- * Enter the shm page into the SHM data structures.
- *
- * This turns the physical page into a swap cache entry.
- */
-static int shm_swapout(struct page * page, struct file *file)
-{
- struct shmid_kernel *shp;
- struct inode * inode = file->f_dentry->d_inode;
- swp_entry_t entry;
- unsigned int idx;
-
- idx = page->index;
- entry = get_swap_page();
- if (!entry.val)
- return -ENOMEM;
-
- /* Add it to the swap cache */
- add_to_swap_cache(page, entry);
- SetPageDirty(page);
-
- /* Add it to the shm data structures */
- swap_duplicate(entry); /* swap-cache and SHM_ENTRY */
- shp = shm_lock(inode->i_ino);
- SHM_ENTRY (shp, idx) = swp_entry_to_pte(entry);
- shm_unlock(inode->i_ino);
-
- /*
- * We had one extra page count for the SHM_ENTRY.
- * We just overwrote it, so we should free that
- * count too (the VM layer will do an additional
- * free that free's the page table count that
- * it got rid of itself).
- */
- page_cache_free(page);
-
- return 0;
-}
-
-/*
- * page not present ... go through shm_dir
- */
-static struct page * shm_nopage_core(struct shmid_kernel *shp, unsigned int idx, int *swp, int *rss, unsigned long address)
-{
- pte_t pte;
- struct page * page;
-
- if (idx >= shp->shm_npages)
- return NOPAGE_SIGBUS;
-
-repeat:
- /* Do we already have the page in memory? */
- pte = SHM_ENTRY(shp,idx);
- if (pte_present(pte)) {
- /* Yes - just increment the page count */
- page = pte_page(pte);
- page_cache_get(page);
- return page;
- }
-
- /* No, but maybe we ahve a page cache entry for it? */
- if (!pte_none(pte)) {
- swp_entry_t entry = pte_to_swp_entry(pte);
-
- shm_unlock(shp->id);
-
- /* Look it up or read it in.. */
- page = lookup_swap_cache(entry);
- if (!page) {
- lock_kernel();
- swapin_readahead(entry);
- page = read_swap_cache(entry);
- unlock_kernel();
- if (!page)
- goto oom;
- }
- if ((shp != shm_lock(shp->id)) && (shp->id != zero_id))
- BUG();
- (*swp)--;
- return page;
- }
-
- /* Ok, get a new page */
- shm_unlock(shp->id);
- page = page_cache_alloc();
- if (!page)
- goto oom;
- clear_user_highpage(page, address);
- if ((shp != shm_lock(shp->id)) && (shp->id != zero_id))
- BUG();
-
- page->index = idx;
- /* Did somebody else allocate it while we slept? */
- if (!pte_none(SHM_ENTRY(shp, idx))) {
- page_cache_free(page);
- goto repeat;
- }
-
- pte = pte_mkdirty(mk_pte(page, PAGE_SHARED));
- SHM_ENTRY(shp, idx) = pte;
- page_cache_get(page); /* one for the page table, once more for SHM_ENTRY */
- return page;
-
-oom:
- shm_lock(shp->id);
- return NOPAGE_OOM;
-}
-
-static struct page * shm_nopage(struct vm_area_struct * shmd, unsigned long address, int no_share)
-{
- struct page * page;
- struct shmid_kernel *shp;
- unsigned int idx;
- struct inode * inode = shmd->vm_file->f_dentry->d_inode;
-
- idx = (address - shmd->vm_start) >> PAGE_SHIFT;
- idx += shmd->vm_pgoff;
-
- down(&inode->i_sem);
- if(!(shp = shm_lock(inode->i_ino)))
- BUG();
- page = shm_nopage_core(shp, idx, &shm_swp, &shm_rss, address);
- shm_unlock(inode->i_ino);
- up(&inode->i_sem);
- return(page);
-}
-
-
-/*
- * Free the swap entry and set the new pte for the shm page.
- */
-static void shm_unuse_page(struct shmid_kernel *shp, unsigned long idx,
- swp_entry_t entry, struct page *page)
-{
- pte_t pte;
-
- pte = pte_mkdirty(mk_pte(page, PAGE_SHARED));
- SHM_ENTRY(shp, idx) = pte;
- page_cache_get(page);
- shm_rss++;
-
- shm_swp--;
-
- swap_free(entry);
-}
-
-static int shm_unuse_core(struct shmid_kernel *shp, swp_entry_t entry, struct page *page)
-{
- int n;
-
- for (n = 0; n < shp->shm_npages; n++) {
- if (pte_none(SHM_ENTRY(shp,n)))
- continue;
- if (pte_present(SHM_ENTRY(shp,n)))
- continue;
- if (pte_to_swp_entry(SHM_ENTRY(shp,n)).val == entry.val) {
- shm_unuse_page(shp, n, entry, page);
- return 1;
- }
- }
- return 0;
-}
-
-/*
- * unuse_shm() search for an eventually swapped out shm page.
- */
-void shm_unuse(swp_entry_t entry, struct page *page)
-{
- int i;
-
- shm_lockall();
- for (i = 0; i <= shm_ids.max_id; i++) {
- struct shmid_kernel *shp = shm_get(i);
- if(shp==NULL)
- continue;
- if (shm_unuse_core(shp, entry, page))
- goto out;
- }
-out:
- shm_unlockall();
- zmap_unuse(entry, page);
-}
-
#ifdef CONFIG_PROC_FS
static int sysvipc_shm_read_proc(char *buffer, char **start, off_t offset, int length, int *eof, void *data)
{
@@ -1561,17 +662,15 @@
int i, len = 0;

down(&shm_ids.sem);
- len += sprintf(buffer, " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime name\n");
+ len += sprintf(buffer, " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime\n");

for(i = 0; i <= shm_ids.max_id; i++) {
struct shmid_kernel* shp;

- if (i == zero_id)
- continue;
shp = shm_lock(i);
if(shp!=NULL) {
-#define SMALL_STRING "%10d %10d %4o %10u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu %.*s%s\n"
-#define BIG_STRING "%10d %10d %4o %21u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu %.*s%s\n"
+#define SMALL_STRING "%10d %10d %4o %10u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
+#define BIG_STRING "%10d %10d %4o %21u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
char *format;

if (sizeof(size_t) <= sizeof(int))
@@ -1585,17 +684,14 @@
shp->shm_segsz,
shp->shm_cprid,
shp->shm_lprid,
- shp->shm_nattch,
+ file_count (shp->shm_file) - 1,
shp->shm_perm.uid,
shp->shm_perm.gid,
shp->shm_perm.cuid,
shp->shm_perm.cgid,
shp->shm_atim,
shp->shm_dtim,
- shp->shm_ctim,
- shp->shm_namelen,
- shp->shm_name,
- shp->shm_flags & SHM_UNLK ? " (deleted)" : "");
+ shp->shm_ctim);
shm_unlock(i);

pos += len;
@@ -1619,153 +715,3 @@
return len;
}
#endif
-
-#define VMA_TO_SHP(vma) ((vma)->vm_file->private_data)
-
-static spinlock_t zmap_list_lock = SPIN_LOCK_UNLOCKED;
-static struct shmid_kernel *zswap_shp = &zshmid_kernel;
-static int zshm_rss;
-
-static struct vm_operations_struct shmzero_vm_ops = {
- open: shmzero_open,
- close: shmzero_close,
- nopage: shmzero_nopage,
- swapout: shm_swapout,
-};
-
-/*
- * In this implementation, the "unuse" and "swapout" interfaces are
- * interlocked out via the kernel_lock, as well as shm_lock(zero_id).
- * "unuse" and "nopage/swapin", as well as "swapout" and "nopage/swapin"
- * interlock via shm_lock(zero_id). All these interlocks can be based
- * on a per mapping lock instead of being a global lock.
- */
-/*
- * Reference (existance) counting on the file/dentry/inode is done
- * by generic vm_file code. The zero code does not hold any reference
- * on the pseudo-file. This is possible because the open/close calls
- * are bracketed by the file count update calls.
- */
-static struct file *file_setup(struct file *fzero, struct shmid_kernel *shp)
-{
- struct file *filp;
- struct inode *inp;
-
- if ((filp = get_empty_filp()) == 0)
- return(filp);
- if ((inp = get_empty_inode()) == 0) {
- put_filp(filp);
- return(0);
- }
- if ((filp->f_dentry = d_alloc(zdent, &(const struct qstr) { "dev/zero",
- 8, 0 })) == 0) {
- iput(inp);
- put_filp(filp);
- return(0);
- }
- filp->f_vfsmnt = mntget(shm_fs_type.kern_mnt);
- d_instantiate(filp->f_dentry, inp);
-
- /*
- * Copy over dev/ino for benefit of procfs. Use
- * ino to indicate seperate mappings.
- */
- filp->f_dentry->d_inode->i_dev = shm_fs_type.kern_mnt->mnt_sb->s_dev;
- filp->f_dentry->d_inode->i_ino = (unsigned long)shp;
- if (fzero)
- fput(fzero); /* release /dev/zero file */
- return(filp);
-}
-
-int map_zero_setup(struct vm_area_struct *vma)
-{
- extern int vm_enough_memory(long pages);
- struct shmid_kernel *shp;
- struct file *filp;
-
- if (!vm_enough_memory((vma->vm_end - vma->vm_start) >> PAGE_SHIFT))
- return -ENOMEM;
- if (IS_ERR(shp = seg_alloc((vma->vm_end - vma->vm_start) / PAGE_SIZE, 0)))
- return PTR_ERR(shp);
- if ((filp = file_setup(vma->vm_file, shp)) == 0) {
- seg_free(shp, 0);
- return -ENOMEM;
- }
- vma->vm_file = filp;
- VMA_TO_SHP(vma) = (void *)shp;
- shp->id = zero_id;
- init_MUTEX(&shp->zsem);
- vma->vm_ops = &shmzero_vm_ops;
- shmzero_open(vma);
- spin_lock(&zmap_list_lock);
- list_add(&shp->zero_list, &zshmid_kernel.zero_list);
- spin_unlock(&zmap_list_lock);
- return 0;
-}
-
-static void shmzero_open(struct vm_area_struct *shmd)
-{
- struct shmid_kernel *shp;
-
- shp = VMA_TO_SHP(shmd);
- down(&shp->zsem);
- shp->shm_nattch++;
- up(&shp->zsem);
-}
-
-static void shmzero_close(struct vm_area_struct *shmd)
-{
- int done = 0;
- struct shmid_kernel *shp;
-
- shp = VMA_TO_SHP(shmd);
- down(&shp->zsem);
- if (--shp->shm_nattch == 0)
- done = 1;
- up(&shp->zsem);
- if (done) {
- spin_lock(&zmap_list_lock);
- if (shp == zswap_shp)
- zswap_shp = list_entry(zswap_shp->zero_list.next,
- struct shmid_kernel, zero_list);
- list_del(&shp->zero_list);
- spin_unlock(&zmap_list_lock);
- seg_free(shp, 0);
- }
-}
-
-static struct page * shmzero_nopage(struct vm_area_struct * shmd, unsigned long address, int no_share)
-{
- struct page *page;
- struct shmid_kernel *shp;
- unsigned int idx;
- int dummy;
-
- idx = (address - shmd->vm_start) >> PAGE_SHIFT;
- idx += shmd->vm_pgoff;
-
- shp = VMA_TO_SHP(shmd);
- down(&shp->zsem);
- shm_lock(zero_id);
- page = shm_nopage_core(shp, idx, &dummy, &zshm_rss, address);
- shm_unlock(zero_id);
- up(&shp->zsem);
- return(page);
-}
-
-static void zmap_unuse(swp_entry_t entry, struct page *page)
-{
- struct shmid_kernel *shp;
-
- spin_lock(&zmap_list_lock);
- shm_lock(zero_id);
- for (shp = list_entry(zshmid_kernel.zero_list.next, struct shmid_kernel,
- zero_list); shp != &zshmid_kernel;
- shp = list_entry(shp->zero_list.next, struct shmid_kernel,
- zero_list)) {
- if (shm_unuse_core(shp, entry, page))
- break;
- }
- shm_unlock(zero_id);
- spin_unlock(&zmap_list_lock);
-}
diff -uNr 4-12-8/ipc/util.c c/ipc/util.c
--- 4-12-8/ipc/util.c Thu Jun 22 16:09:45 2000
+++ c/ipc/util.c Mon Dec 11 19:42:35 2000
@@ -345,11 +345,6 @@
return;
}

-int shm_swap (int prio, int gfp_mask)
-{
- return 0;
-}
-
asmlinkage long sys_semget (key_t key, int nsems, int semflg)
{
return -ENOSYS;
@@ -404,15 +399,6 @@
asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds *buf)
{
return -ENOSYS;
-}
-
-void shm_unuse(swp_entry_t entry, struct page *page)
-{
-}
-
-int map_zero_setup(struct vm_area_struct *vma)
-{
- return -EINVAL;
}

#endif /* CONFIG_SYSVIPC */
diff -uNr 4-12-8/kernel/sysctl.c c/kernel/sysctl.c
--- 4-12-8/kernel/sysctl.c Mon Dec 11 19:41:43 2000
+++ c/kernel/sysctl.c Mon Dec 11 19:42:35 2000
@@ -63,6 +63,8 @@
#endif
#ifdef CONFIG_SYSVIPC
extern size_t shm_ctlmax;
+extern size_t shm_ctlall;
+extern int shm_ctlmni;
extern int msg_ctlmax;
extern int msg_ctlmnb;
extern int msg_ctlmni;
@@ -208,6 +210,10 @@
#ifdef CONFIG_SYSVIPC
{KERN_SHMMAX, "shmmax", &shm_ctlmax, sizeof (size_t),
0644, NULL, &proc_doulongvec_minmax},
+ {KERN_SHMALL, "shmall", &shm_ctlall, sizeof (size_t),
+ 0644, NULL, &proc_doulongvec_minmax},
+ {KERN_SHMMNI, "shmmni", &shm_ctlmni, sizeof (int),
+ 0644, NULL, &proc_dointvec},
{KERN_MSGMAX, "msgmax", &msg_ctlmax, sizeof (int),
0644, NULL, &proc_dointvec},
{KERN_MSGMNI, "msgmni", &msg_ctlmni, sizeof (int),
diff -uNr 4-12-8/mm/Makefile c/mm/Makefile
--- 4-12-8/mm/Makefile Sun Oct 8 17:57:35 2000
+++ c/mm/Makefile Mon Dec 11 19:42:35 2000
@@ -10,7 +10,8 @@
O_TARGET := mm.o
O_OBJS := memory.o mmap.o filemap.o mprotect.o mlock.o mremap.o \
vmalloc.o slab.o bootmem.o swap.o vmscan.o page_io.o \
- page_alloc.o swap_state.o swapfile.o numa.o oom_kill.o
+ page_alloc.o swap_state.o swapfile.o numa.o oom_kill.o \
+ shmem.o

ifeq ($(CONFIG_HIGHMEM),y)
O_OBJS += highmem.o
diff -uNr 4-12-8/mm/filemap.c c/mm/filemap.c
--- 4-12-8/mm/filemap.c Mon Dec 11 19:41:43 2000
+++ c/mm/filemap.c Mon Dec 11 19:42:35 2000
@@ -542,8 +542,8 @@
* a rather lightweight function, finding and getting a reference to a
* hashed page atomically, waiting for it if it's locked.
*/
-static struct page * __find_get_page(struct address_space *mapping,
- unsigned long offset, struct page **hash)
+struct page * __find_get_page(struct address_space *mapping,
+ unsigned long offset, struct page **hash)
{
struct page *page;

diff -uNr 4-12-8/mm/mmap.c c/mm/mmap.c
--- 4-12-8/mm/mmap.c Sun Nov 12 04:02:40 2000
+++ c/mm/mmap.c Mon Dec 11 19:42:35 2000
@@ -333,7 +333,7 @@
if (error)
goto unmap_and_free_vma;
} else if (flags & MAP_SHARED) {
- error = map_zero_setup(vma);
+ error = shmem_zero_setup(vma);
if (error)
goto free_vma;
}
diff -uNr 4-12-8/mm/shmem.c c/mm/shmem.c
--- 4-12-8/mm/shmem.c Thu Jan 1 01:00:00 1970
+++ c/mm/shmem.c Wed Dec 13 11:04:25 2000
@@ -0,0 +1,897 @@
+/*
+ * Resizable simple shmem filesystem for Linux.
+ *
+ * Copyright (C) 2000 Linus Torvalds.
+ * 2000 Transmeta Corp.
+ * 2000 Christoph Rohland
+ *
+ * This file is released under the GPL.
+ */
+
+/*
+ * This shared memory handling is heavily based on the ramfs. It
+ * extends the ramfs by the ability to use swap which would makes it a
+ * completely usable filesystem.
+ *
+ * But read and write are not supported (yet)
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/devfs_fs_kernel.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/file.h>
+#include <linux/swap.h>
+#include <linux/pagemap.h>
+#include <linux/init.h>
+#include <linux/string.h>
+#include <linux/locks.h>
+#include <asm/smplock.h>
+
+#include <asm/uaccess.h>
+
+#define SHMEM_MAGIC 0x01021994
+
+#define ENTRIES_PER_PAGE (PAGE_SIZE/sizeof(unsigned long))
+#define NR_SINGLE (ENTRIES_PER_PAGE + SHMEM_NR_DIRECT)
+
+static struct super_operations shmem_ops;
+static struct address_space_operations shmem_aops;
+static struct file_operations shmem_file_operations;
+static struct inode_operations shmem_inode_operations;
+static struct file_operations shmem_dir_operations;
+static struct inode_operations shmem_dir_inode_operations;
+static struct vm_operations_struct shmem_vm_ops;
+
+LIST_HEAD (shmem_inodes);
+static spinlock_t shmem_ilock = SPIN_LOCK_UNLOCKED;
+
+static inline swp_entry_t * shmem_swp_entry (struct shmem_inode_info *info, unsigned long index)
+{
+ if (index < SHMEM_NR_DIRECT)
+ return info->i_direct+index;
+
+ index -= SHMEM_NR_DIRECT;
+ if (index < ENTRIES_PER_PAGE) {
+ if (!info->i_indirect){
+ info->i_indirect = (swp_entry_t *) get_zeroed_page(GFP_USER);
+ if (!info->i_indirect)
+ return NULL;
+ }
+
+ return info->i_indirect+index;
+ }
+
+ index -= ENTRIES_PER_PAGE;
+ if (index >= ENTRIES_PER_PAGE*ENTRIES_PER_PAGE)
+ return NULL;
+
+ if (!info->i_double) {
+ info->i_double = (swp_entry_t **) get_zeroed_page(GFP_USER);
+ if (!info->i_double)
+ return NULL;
+ }
+ if(!(info->i_double[index/ENTRIES_PER_PAGE])) {
+ info->i_double[index/ENTRIES_PER_PAGE] = (swp_entry_t *) get_zeroed_page(GFP_USER);
+ if (!info->i_double[index/ENTRIES_PER_PAGE])
+ return NULL;
+ }
+
+ return info->i_double[index/ENTRIES_PER_PAGE]+index%ENTRIES_PER_PAGE;
+}
+
+static int shmem_free_swp(swp_entry_t *dir, unsigned int count)
+{
+ swp_entry_t *ptr;
+ struct page * page;
+ int freed = 0;
+
+ for (ptr = dir; ptr < dir + count; ptr++) {
+ if (!ptr->val)
+ continue;
+ swap_free (*ptr);
+ if (!(page = lookup_swap_cache(*ptr)))
+ continue;
+ freed--;
+ delete_from_swap_cache(page);
+ page_cache_release(page);
+ }
+ return freed;
+}
+
+/*
+ * shmem_truncate_part - free a bunch of swap entries
+ *
+ * @dir: pointer to swp_entries
+ * @size: number of entries in dir
+ * @start: offset to start from
+ * @inode: inode for statistics
+ *
+ * It frees the swap entries from dir+start til dir+size
+ *
+ * returns 0 if it truncated something, else (offset-size)
+ */
+
+static unsigned long
+shmem_truncate_part (swp_entry_t * dir, unsigned long size,
+ unsigned long start, struct inode * inode) {
+ unsigned long freed = 0;
+ if (start > size)
+ return start - size;
+ if (dir) {
+ freed = shmem_free_swp (dir+start, size-start);
+ memset(dir+start, 0, (size-start) * sizeof (swp_entry_t));
+ }
+
+ spin_lock (&inode->u.shmem_i.stat_lock);
+ inode->u.shmem_i.swapped -= freed;
+ spin_unlock (&inode->u.shmem_i.stat_lock);
+ return 0;
+}
+
+static void shmem_truncate (struct inode * inode)
+{
+ int clear_base;
+ unsigned long start;
+ unsigned long freed = 0;
+ swp_entry_t **base, **ptr;
+ struct shmem_inode_info * info = &inode->u.shmem_i;
+
+ start = (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+
+ start = shmem_truncate_part (info->i_direct, SHMEM_NR_DIRECT, start, inode);
+
+ if (start) {
+ start = shmem_truncate_part (info->i_indirect, ENTRIES_PER_PAGE, start, inode);
+ } else if (info->i_indirect) {
+ freed += shmem_free_swp (info->i_indirect, ENTRIES_PER_PAGE);
+ free_page ((unsigned long) info->i_indirect);
+ info->i_indirect = 0;
+ }
+
+ if (!(base = info->i_double))
+ goto out;;
+
+ clear_base = 1;
+ for (ptr = base; ptr < base + ENTRIES_PER_PAGE; ptr++) {
+ if (!start) {
+ if (!*ptr)
+ continue;
+ freed += shmem_free_swp (*ptr, ENTRIES_PER_PAGE);
+ free_page ((unsigned long) *ptr);
+ *ptr = 0;
+ continue;
+ }
+ clear_base = 0;
+ start = shmem_truncate_part (info->i_indirect, ENTRIES_PER_PAGE, start, inode);
+ }
+
+ if (!clear_base)
+ goto out;
+
+ free_page ((unsigned long)base);
+ info->i_double = 0;
+
+out:
+ spin_lock (&info->stat_lock);
+ info->swapped -= freed;
+ spin_unlock (&info->stat_lock);
+ inode->i_blocks -= freed;
+
+ /*
+ * We have to calculate the free blocks since we do not know
+ * how many pages the mm discarded
+ *
+ * But we know that normally
+ * inodes->i_blocks == inode->i_mapping->nrpages + info->swapped
+ *
+ * So the mm freed
+ * inodes->i_blocks - (inode->i_mapping->nrpages + info->swapped)
+ */
+
+ spin_lock (&pagecache_lock); /* protect inode->i_mapping->nrpages */
+ freed = inode->i_blocks - (inode->i_mapping->nrpages + info->swapped);
+ inode->i_blocks -= freed;
+ spin_unlock (&pagecache_lock);
+
+ spin_lock (&inode->i_sb->u.shmem_sb.stat_lock);
+ inode->i_sb->u.shmem_sb.free_blocks += freed;
+ spin_unlock (&inode->i_sb->u.shmem_sb.stat_lock);
+}
+
+static void shmem_delete_inode(struct inode * inode)
+{
+ struct shmem_sb_info *info = &inode->i_sb->u.shmem_sb;
+
+ spin_lock (&shmem_ilock);
+ list_del (&inode->u.shmem_i.list);
+ spin_unlock (&shmem_ilock);
+ inode->i_size = 0;
+ shmem_truncate (inode);
+ spin_lock (&info->stat_lock);
+ info->free_inodes++;
+ spin_unlock (&info->stat_lock);
+ clear_inode(inode);
+}
+
+struct inode *shmem_get_inode(struct super_block *sb, int mode, int dev)
+{
+ struct inode * inode;
+
+ spin_lock (&sb->u.shmem_sb.stat_lock);
+ if (!sb->u.shmem_sb.free_inodes) {
+ spin_unlock (&sb->u.shmem_sb.stat_lock);
+ return NULL;
+ }
+ sb->u.shmem_sb.free_inodes--;
+ spin_unlock (&sb->u.shmem_sb.stat_lock);
+
+ inode = new_inode(sb);
+ if (inode) {
+ inode->i_mode = mode;
+ inode->i_uid = current->fsuid;
+ inode->i_gid = current->fsgid;
+ inode->i_blksize = PAGE_CACHE_SIZE;
+ inode->i_blocks = 0;
+ inode->i_rdev = to_kdev_t(dev);
+ inode->i_mapping->a_ops = &shmem_aops;
+ inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+ spin_lock_init (&inode->u.shmem_i.stat_lock);
+ switch (mode & S_IFMT) {
+ default:
+ init_special_inode(inode, mode, dev);
+ break;
+ case S_IFREG:
+ inode->i_op = &shmem_inode_operations;
+ inode->i_fop = &shmem_file_operations;
+ break;
+ case S_IFDIR:
+ inode->i_op = &shmem_dir_inode_operations;
+ inode->i_fop = &shmem_dir_operations;
+ break;
+ case S_IFLNK:
+ inode->i_op = &page_symlink_inode_operations;
+ break;
+ }
+ spin_lock (&shmem_ilock);
+ list_add (&inode->u.shmem_i.list, &shmem_inodes);
+ spin_unlock (&shmem_ilock);
+ }
+ return inode;
+}
+
+static int shmem_statfs(struct super_block *sb, struct statfs *buf)
+{
+ buf->f_type = SHMEM_MAGIC;
+ buf->f_bsize = PAGE_CACHE_SIZE;
+ spin_lock (&sb->u.shmem_sb.stat_lock);
+ if (sb->u.shmem_sb.max_blocks != ULONG_MAX ||
+ sb->u.shmem_sb.max_inodes != ULONG_MAX) {
+ buf->f_blocks = sb->u.shmem_sb.max_blocks;
+ buf->f_bavail = buf->f_bfree = sb->u.shmem_sb.free_blocks;
+ buf->f_files = sb->u.shmem_sb.max_inodes;
+ buf->f_ffree = sb->u.shmem_sb.free_inodes;
+ }
+ spin_unlock (&sb->u.shmem_sb.stat_lock);
+ buf->f_namelen = 255;
+ return 0;
+}
+
+/*
+ * Lookup the data. This is trivial - if the dentry didn't already
+ * exist, we know it is negative.
+ */
+static struct dentry * shmem_lookup(struct inode *dir, struct dentry *dentry)
+{
+ d_add(dentry, NULL);
+ return NULL;
+}
+
+/*
+ * File creation. Allocate an inode, and we're done..
+ */
+static int shmem_mknod(struct inode *dir, struct dentry *dentry, int mode, int dev)
+{
+ struct inode * inode = shmem_get_inode(dir->i_sb, mode, dev);
+ int error = -ENOSPC;
+
+ if (inode) {
+ d_instantiate(dentry, inode);
+ dget(dentry); /* Extra count - pin the dentry in core */
+ error = 0;
+ }
+ return error;
+}
+
+static int shmem_mkdir(struct inode * dir, struct dentry * dentry, int mode)
+{
+ return shmem_mknod(dir, dentry, mode | S_IFDIR, 0);
+}
+
+static int shmem_create(struct inode *dir, struct dentry *dentry, int mode)
+{
+ return shmem_mknod(dir, dentry, mode | S_IFREG, 0);
+}
+
+/*
+ * Link a file..
+ */
+static int shmem_link(struct dentry *old_dentry, struct inode * dir, struct dentry * dentry)
+{
+ struct inode *inode = old_dentry->d_inode;
+
+ if (S_ISDIR(inode->i_mode))
+ return -EPERM;
+
+ inode->i_nlink++;
+ atomic_inc(&inode->i_count); /* New dentry reference */
+ dget(dentry); /* Extra pinning count for the created dentry */
+ d_instantiate(dentry, inode);
+ return 0;
+}
+
+static inline int shmem_positive(struct dentry *dentry)
+{
+ return dentry->d_inode && !d_unhashed(dentry);
+}
+
+/*
+ * Check that a directory is empty (this works
+ * for regular files too, they'll just always be
+ * considered empty..).
+ *
+ * Note that an empty directory can still have
+ * children, they just all have to be negative..
+ */
+static int shmem_empty(struct dentry *dentry)
+{
+ struct list_head *list;
+
+ spin_lock(&dcache_lock);
+ list = dentry->d_subdirs.next;
+
+ while (list != &dentry->d_subdirs) {
+ struct dentry *de = list_entry(list, struct dentry, d_child);
+
+ if (shmem_positive(de)) {
+ spin_unlock(&dcache_lock);
+ return 0;
+ }
+ list = list->next;
+ }
+ spin_unlock(&dcache_lock);
+ return 1;
+}
+
+/*
+ * This works for both directories and regular files.
+ * (non-directories will always have empty subdirs)
+ */
+static int shmem_unlink(struct inode * dir, struct dentry *dentry)
+{
+ int retval = -ENOTEMPTY;
+
+ if (shmem_empty(dentry)) {
+ struct inode *inode = dentry->d_inode;
+
+ inode->i_nlink--;
+ dput(dentry); /* Undo the count from "create" - this does all the work */
+ retval = 0;
+ }
+ return retval;
+}
+
+#define shmem_rmdir shmem_unlink
+
+/*
+ * The VFS layer already does all the dentry stuff for rename,
+ * we just have to decrement the usage count for the target if
+ * it exists so that the VFS layer correctly free's it when it
+ * gets overwritten.
+ */
+static int shmem_rename(struct inode * old_dir, struct dentry *old_dentry, struct inode * new_dir,struct dentry *new_dentry)
+{
+ int error = -ENOTEMPTY;
+
+ if (shmem_empty(new_dentry)) {
+ struct inode *inode = new_dentry->d_inode;
+ if (inode) {
+ inode->i_nlink--;
+ dput(new_dentry);
+ }
+ error = 0;
+ }
+ return error;
+}
+
+static int shmem_symlink(struct inode * dir, struct dentry *dentry, const char * symname)
+{
+ int error;
+
+ error = shmem_mknod(dir, dentry, S_IFLNK | S_IRWXUGO, 0);
+ if (!error) {
+ int l = strlen(symname)+1;
+ struct inode *inode = dentry->d_inode;
+ error = block_symlink(inode, symname, l);
+ }
+ return error;
+}
+
+static int shmem_mmap(struct file * file, struct vm_area_struct * vma)
+{
+ UPDATE_ATIME(file->f_dentry->d_inode);
+ vma->vm_ops = &shmem_vm_ops;
+ return 0;
+}
+
+/*
+ * We mark int dirty so the vm will not simply drop it
+ * The real work is done in shmem_writepage
+ */
+
+int shmem_swapout(struct page * page, struct file *file)
+{
+ SetPageDirty (page);
+ if (file->private_data) /* hack for SHM_LOCK */
+ return -EPERM;
+ return 0;
+}
+
+/*
+ * Move the page from the page cache to the swap cache
+ */
+static int shmem_writepage(struct page * page)
+{
+ struct inode *inode = (struct inode *)page->mapping->host;
+ swp_entry_t *entry;
+
+ entry = shmem_swp_entry (&inode->u.shmem_i, page->index);
+ if (!entry) /* this had been allocted on page allocation */
+ BUG();
+ if (entry->val)
+ BUG();
+
+ *entry = __get_swap_page(2);
+ if (!entry->val)
+ return -ENOMEM;
+
+ /* Remove it from the page cache */
+ lru_cache_del(page);
+ remove_inode_page(page);
+ /* Add it to the swap cache */
+ add_to_swap_cache(page, *entry);
+ page_cache_release(page);
+ SetPageDirty(page);
+ UnlockPage(page);
+ spin_lock(&inode->u.shmem_i.stat_lock);
+ inode->u.shmem_i.swapped++;
+ spin_unlock(&inode->u.shmem_i.stat_lock);
+ return 0;
+}
+
+/*
+ * shmem_nopage - either get the page from swap or allocate a new one
+ *
+ * If we allocate a new one we do not mark it dirty. That's up to the
+ * vm. If we swap it in we mark it dirty since we also free the swap
+ * entry since a page cannot live in both the swap and page cache
+ */
+struct page * shmem_nopage(struct vm_area_struct * vma, unsigned long address, int no_share)
+{
+ unsigned long size;
+ struct page * page;
+ unsigned int idx;
+ swp_entry_t *entry;
+ struct inode * inode = vma->vm_file->f_dentry->d_inode;
+ struct address_space * mapping = inode->i_mapping;
+
+ idx = (address - vma->vm_start) >> PAGE_SHIFT;
+ idx += vma->vm_pgoff;
+
+ size = (inode->i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+ if ((idx >= size) && (vma->vm_mm == current->mm))
+ return NULL;
+
+#ifdef notyet
+ /* Do we already have the page in memory? */
+ page = __find_get_page(mapping, idx, page_hash (mapping, idx));
+ if (page)
+ return page;
+#endif
+
+ down (&inode->i_sem);
+ /* retry, we may have slept */
+ page = __find_lock_page(mapping, idx, page_hash (mapping, idx));
+ if (page)
+ goto out;
+
+ entry = shmem_swp_entry (&inode->u.shmem_i, idx);
+ if (!entry)
+ goto oom;
+ if (entry->val) {
+ unsigned long flags;
+
+ /* Look it up and read it in.. */
+ page = lookup_swap_cache(*entry);
+ if (!page) {
+ lock_kernel();
+ swapin_readahead(*entry);
+ page = read_swap_cache(*entry);
+ unlock_kernel();
+ if (!page)
+ goto oom;
+ }
+
+ swap_free(*entry);
+ /* We have to this with page locked to prevent races
+ with shmem_writepage */
+ lock_page(page);
+ delete_from_swap_cache_nolock(page);
+ *entry = (swp_entry_t) {0};
+ flags = page->flags & ~((1 << PG_uptodate) | (1 << PG_error) | (1 << PG_referenced) | (1 << PG_arch_1));
+ page->flags = flags | (1 << PG_dirty);
+ add_to_page_cache_locked(page, mapping, idx);
+ spin_lock (&inode->u.shmem_i.stat_lock);
+ inode->u.shmem_i.swapped--;
+ spin_unlock (&inode->u.shmem_i.stat_lock);
+ } else {
+ spin_lock (&inode->i_sb->u.shmem_sb.stat_lock);
+ if (inode->i_sb->u.shmem_sb.free_blocks == 0)
+ goto no_space;
+ inode->i_sb->u.shmem_sb.free_blocks--;
+ spin_unlock (&inode->i_sb->u.shmem_sb.stat_lock);
+ /* Ok, get a new page */
+ page = page_cache_alloc();
+ if (!page)
+ goto oom;
+ clear_user_highpage(page, address);
+ inode->i_blocks++;
+ add_to_page_cache (page, mapping, idx);
+ }
+ /* We have the page */
+ SetPageUptodate (page);
+out:
+ UnlockPage (page);
+ up(&inode->i_sem);
+
+ if (no_share) {
+ struct page *new_page = page_cache_alloc();
+
+ if (new_page) {
+ copy_user_highpage(new_page, page, address);
+ flush_page_to_ram(new_page);
+ } else
+ new_page = NOPAGE_OOM;
+ page_cache_release(page);
+ return new_page;
+ }
+
+ flush_page_to_ram (page);
+ return(page);
+no_space:
+ spin_unlock (&inode->i_sb->u.shmem_sb.stat_lock);
+oom:
+ printk ("shmem oom\n");
+ page = NOPAGE_OOM;
+ up(&inode->i_sem);
+ return page;
+}
+
+static int shmem_parse_options(char *options, int *mode, unsigned long * blocks, unsigned long *inodes)
+{
+ char *this_char, *value;
+
+ this_char = NULL;
+ if ( options )
+ this_char = strtok(options,",");
+ for ( ; this_char; this_char = strtok(NULL,",")) {
+ if ((value = strchr(this_char,'=')) != NULL)
+ *value++ = 0;
+ if (!strcmp(this_char,"nr_blocks")) {
+ if (!value || !*value || !blocks)
+ return 1;
+ *blocks = simple_strtoul(value,&value,0);
+ if (*value)
+ return 1;
+ } else if (!strcmp(this_char,"nr_inodes")) {
+ if (!value || !*value || !inodes)
+ return 1;
+ *inodes = simple_strtoul(value,&value,0);
+ if (*value)
+ return 1;
+ } else if (!strcmp(this_char,"mode")) {
+ if (!value || !*value || !mode)
+ return 1;
+ *mode = simple_strtoul(value,&value,8);
+ if (*value)
+ return 1;
+ }
+ else
+ return 1;
+ }
+
+ return 0;
+}
+
+static struct super_block *shmem_read_super(struct super_block * sb, void * data, int silent)
+{
+ struct inode * inode;
+ struct dentry * root;
+ unsigned long blocks = ULONG_MAX; /* unlimited */
+ unsigned long inodes = ULONG_MAX; /* unlimited */
+ int mode = S_IRWXUGO | S_ISVTX;
+
+ if (shmem_parse_options (data, &mode, &blocks, &inodes)) {
+ printk(KERN_ERR "shmem fs invalid option\n");
+ return NULL;
+ }
+
+ spin_lock_init (&sb->u.shmem_sb.stat_lock);
+ sb->u.shmem_sb.max_blocks = blocks;
+ sb->u.shmem_sb.free_blocks = blocks;
+ sb->u.shmem_sb.max_inodes = inodes;
+ sb->u.shmem_sb.free_inodes = inodes;
+ sb->s_blocksize = PAGE_CACHE_SIZE;
+ sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
+ sb->s_magic = SHMEM_MAGIC;
+ sb->s_op = &shmem_ops;
+ inode = shmem_get_inode(sb, S_IFDIR | mode, 0);
+ if (!inode)
+ return NULL;
+
+ root = d_alloc_root(inode);
+ if (!root) {
+ iput(inode);
+ return NULL;
+ }
+ sb->s_root = root;
+ return sb;
+}
+
+static int shmem_remount_fs (struct super_block *sb, int *flags, char *data)
+{
+ int error;
+ unsigned long max_blocks, blocks;
+ unsigned long max_inodes, inodes;
+ struct shmem_sb_info *info = &sb->u.shmem_sb;
+
+ if (shmem_parse_options (data, NULL, &max_blocks, &max_inodes))
+ return -EINVAL;
+
+ spin_lock(&info->stat_lock);
+ blocks = info->max_blocks - info->free_blocks;
+ inodes = info->max_inodes - info->free_inodes;
+ error = -EINVAL;
+ if (max_blocks < blocks)
+ goto out;
+ if (max_inodes < inodes)
+ goto out;
+ error = 0;
+ info->max_blocks = max_blocks;
+ info->free_blocks = max_blocks - blocks;
+ info->max_inodes = max_inodes;
+ info->free_inodes = max_inodes - inodes;
+out:
+ spin_unlock(&info->stat_lock);
+ return error;
+}
+
+static struct address_space_operations shmem_aops = {
+ writepage: shmem_writepage
+};
+
+static struct file_operations shmem_file_operations = {
+ mmap: shmem_mmap
+};
+
+static struct inode_operations shmem_inode_operations = {
+ truncate: shmem_truncate,
+};
+
+static struct file_operations shmem_dir_operations = {
+ read: generic_read_dir,
+ readdir: dcache_readdir,
+};
+
+static struct inode_operations shmem_dir_inode_operations = {
+ create: shmem_create,
+ lookup: shmem_lookup,
+ link: shmem_link,
+ unlink: shmem_unlink,
+ symlink: shmem_symlink,
+ mkdir: shmem_mkdir,
+ rmdir: shmem_rmdir,
+ mknod: shmem_mknod,
+ rename: shmem_rename,
+};
+
+static struct super_operations shmem_ops = {
+ statfs: shmem_statfs,
+ remount_fs: shmem_remount_fs,
+ delete_inode: shmem_delete_inode,
+ put_inode: force_delete,
+};
+
+
+static struct vm_operations_struct shmem_vm_ops = {
+ nopage: shmem_nopage,
+ swapout:shmem_swapout,
+};
+
+static DECLARE_FSTYPE(shmem_fs_type, "shm", shmem_read_super, FS_LITTER);
+
+static int __init init_shmem_fs(void)
+{
+ int error;
+ struct vfsmount * res;
+
+ if ((error = register_filesystem(&shmem_fs_type))) {
+ printk (KERN_ERR "Could not register shmem fs\n");
+ return error;
+ }
+
+ res = kern_mount(&shmem_fs_type);
+ if (IS_ERR (res)) {
+ printk (KERN_ERR "could not kern_mount shmem fs\n");
+ unregister_filesystem(&shmem_fs_type);
+ return PTR_ERR(res);
+ }
+
+ devfs_mk_dir (NULL, "shm", NULL);
+ return 0;
+}
+
+static void __exit exit_shmem_fs(void)
+{
+ unregister_filesystem(&shmem_fs_type);
+}
+
+module_init(init_shmem_fs)
+module_exit(exit_shmem_fs)
+
+static int shmem_clear_swp (swp_entry_t entry, swp_entry_t *ptr, int size) {
+ swp_entry_t *test;
+
+ for (test = ptr; test < ptr + size; test++) {
+ if (test->val == entry.val) {
+ swap_free (entry);
+ *test = (swp_entry_t) {0};
+ return test - ptr;
+ }
+ }
+ return -1;
+}
+
+static int shmem_unuse_inode (struct inode *inode, swp_entry_t entry, struct page *page)
+{
+ swp_entry_t **base, **ptr;
+ unsigned long idx;
+ int offset;
+
+ idx = 0;
+ if ((offset = shmem_clear_swp (entry, inode->u.shmem_i.i_direct, SHMEM_NR_DIRECT)) >= 0)
+ goto found;
+
+ idx = SHMEM_NR_DIRECT;
+ if (inode->u.shmem_i.i_indirect &&
+ (offset = shmem_clear_swp (entry, inode->u.shmem_i.i_indirect, ENTRIES_PER_PAGE)) >= 0)
+ goto found;
+
+ if (!(base = inode->u.shmem_i.i_double))
+ return 0;
+
+ idx = SHMEM_NR_DIRECT + ENTRIES_PER_PAGE;
+ for (ptr = base; ptr < base + ENTRIES_PER_PAGE; ptr++) {
+ if (*ptr &&
+ (offset = shmem_clear_swp (entry, *ptr, ENTRIES_PER_PAGE)) >= 0)
+ goto found;
+ idx += ENTRIES_PER_PAGE;
+ }
+ return 0;
+found:
+ delete_from_swap_cache (page);
+ add_to_page_cache (page, inode->i_mapping, idx);
+ SetPageDirty (page);
+ SetPageUptodate (page);
+ UnlockPage (page);
+ spin_lock (&inode->u.shmem_i.stat_lock);
+ inode->u.shmem_i.swapped--;
+ spin_unlock (&inode->u.shmem_i.stat_lock);
+ return 1;
+}
+
+/*
+ * unuse_shmem() search for an eventually swapped out shmem page.
+ */
+void shmem_unuse(swp_entry_t entry, struct page *page)
+{
+ struct list_head *p;
+ struct inode * inode;
+
+ spin_lock (&shmem_ilock);
+ list_for_each(p, &shmem_inodes) {
+ inode = list_entry(p, struct inode, u.shmem_i.list);
+
+ if (shmem_unuse_inode(inode, entry, page))
+ break;
+ }
+ spin_unlock (&shmem_ilock);
+}
+
+
+/*
+ * shmem_file_setup - get an unlinked file living in shmem fs
+ *
+ * @name: name for dentry (to be seen in /proc/<pid>/maps
+ * @size: size to be set for the file
+ *
+ */
+struct file *shmem_file_setup(char * name, loff_t size)
+{
+ int error;
+ struct file *file;
+ struct inode * inode;
+ struct dentry *dentry, *root;
+ struct qstr this;
+ int vm_enough_memory(long pages);
+
+ error = -ENOMEM;
+ if (!vm_enough_memory((size) >> PAGE_SHIFT))
+ goto out;
+
+ this.name = name;
+ this.len = strlen(name);
+ this.hash = 0; /* will go */
+ root = shmem_fs_type.kern_mnt->mnt_root;
+ dentry = d_alloc(root, &this);
+ if (!dentry)
+ goto out;
+
+ error = -ENFILE;
+ file = get_empty_filp();
+ if (!file)
+ goto put_dentry;
+
+ error = -ENOSPC;
+ inode = shmem_get_inode(root->d_sb, S_IFREG | S_IRWXUGO, 0);
+ if (!inode)
+ goto close_file;
+
+ d_instantiate(dentry, inode);
+ dentry->d_inode->i_size = size;
+ file->f_vfsmnt = mntget(shmem_fs_type.kern_mnt);
+ file->f_dentry = dentry;
+ file->f_op = &shmem_file_operations;
+ file->f_mode = FMODE_WRITE | FMODE_READ;
+ inode->i_nlink = 0; /* It is unlinked */
+ return(file);
+
+close_file:
+ put_filp(file);
+put_dentry:
+ dput (dentry);
+out:
+ return ERR_PTR(error);
+}
+/*
+ * shmem_zero_setup - setup a shared anonymous mapping
+ *
+ * @vma: the vma to be mmapped is prepared by do_mmap_pgoff
+ */
+int shmem_zero_setup(struct vm_area_struct *vma)
+{
+ struct file *file;
+ loff_t size = vma->vm_end - vma->vm_start;
+
+ file = shmem_file_setup("dev/zero", size);
+ if (IS_ERR(file))
+ return PTR_ERR(file);
+
+ if (vma->vm_file)
+ fput (vma->vm_file);
+ vma->vm_file = file;
+ vma->vm_ops = &shmem_vm_ops;
+ return 0;
+}
diff -uNr 4-12-8/mm/swapfile.c c/mm/swapfile.c
--- 4-12-8/mm/swapfile.c Fri Dec 1 23:42:45 2000
+++ c/mm/swapfile.c Mon Dec 11 19:42:35 2000
@@ -375,7 +375,7 @@
for_each_task(p)
unuse_process(p->mm, entry, page);
read_unlock(&tasklist_lock);
- shm_unuse(entry, page);
+ shmem_unuse(entry, page);
/* Now get rid of the extra reference to the temporary
page we've been using. */
if (PageSwapCache(page))
-
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