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Subject[patch 3/3] epoll optimizations and cleanups ...

This patch cuts out lots of code from epoll, by reusing the anonymous
inode source of patch 2/3.



Signed-off-by: Davide Libenzi <davidel@xmailserver.org>



- Davide



eventpoll.c | 174 +-----------------------------------------------------------
1 file changed, 3 insertions(+), 171 deletions(-)


Index: linux-2.6.20.ep2/fs/eventpoll.c
===================================================================
--- linux-2.6.20.ep2.orig/fs/eventpoll.c 2007-03-06 11:09:00.000000000 -0800
+++ linux-2.6.20.ep2/fs/eventpoll.c 2007-03-06 11:12:43.000000000 -0800
@@ -35,6 +35,7 @@
#include <linux/mount.h>
#include <linux/bitops.h>
#include <linux/mutex.h>
+#include <linux/anon_inodes.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/io.h>
@@ -76,8 +77,6 @@
*/


-#define EVENTPOLLFS_MAGIC 0x03111965 /* My birthday should work for this :) */
-
#define DEBUG_EPOLL 0

#if DEBUG_EPOLL > 0
@@ -229,8 +228,6 @@

static void ep_poll_safewake_init(struct poll_safewake *psw);
static void ep_poll_safewake(struct poll_safewake *psw, wait_queue_head_t *wq);
-static int ep_getfd(int *efd, struct inode **einode, struct file **efile,
- struct eventpoll *ep);
static int ep_alloc(struct eventpoll **pep);
static void ep_free(struct eventpoll *ep);
static struct epitem *ep_find(struct eventpoll *ep, struct file *file, int fd);
@@ -256,11 +253,6 @@
int maxevents);
static int ep_poll(struct eventpoll *ep, struct epoll_event __user *events,
int maxevents, long timeout);
-static int eventpollfs_delete_dentry(struct dentry *dentry);
-static struct inode *ep_eventpoll_inode(void);
-static int eventpollfs_get_sb(struct file_system_type *fs_type,
- int flags, const char *dev_name,
- void *data, struct vfsmount *mnt);

/*
* This semaphore is used to serialize ep_free() and eventpoll_release_file().
@@ -276,30 +268,12 @@
/* Slab cache used to allocate "struct eppoll_entry" */
static struct kmem_cache *pwq_cache __read_mostly;

-/* Virtual fs used to allocate inodes for eventpoll files */
-static struct vfsmount *eventpoll_mnt __read_mostly;
-
/* File callbacks that implement the eventpoll file behaviour */
static const struct file_operations eventpoll_fops = {
.release = ep_eventpoll_close,
.poll = ep_eventpoll_poll
};

-/*
- * This is used to register the virtual file system from where
- * eventpoll inodes are allocated.
- */
-static struct file_system_type eventpoll_fs_type = {
- .name = "eventpollfs",
- .get_sb = eventpollfs_get_sb,
- .kill_sb = kill_anon_super,
-};
-
-/* Very basic directory entry operations for the eventpoll virtual file system */
-static struct dentry_operations eventpollfs_dentry_operations = {
- .d_delete = eventpollfs_delete_dentry,
-};
-


/* Fast test to see if the file is an evenpoll file */
@@ -496,7 +470,8 @@
* Creates all the items needed to setup an eventpoll file. That is,
* a file structure, and inode and a free file descriptor.
*/
- error = ep_getfd(&fd, &inode, &file, ep);
+ error = aino_getfd(&fd, &inode, &file, "[eventpoll]",
+ &eventpoll_fops, ep);
if (error)
goto eexit_2;

@@ -726,82 +701,6 @@
#endif /* #ifdef TIF_RESTORE_SIGMASK */


-/*
- * Creates the file descriptor to be used by the epoll interface.
- */
-static int ep_getfd(int *efd, struct inode **einode, struct file **efile,
- struct eventpoll *ep)
-{
- struct qstr this;
- char name[32];
- struct dentry *dentry;
- struct inode *inode;
- struct file *file;
- int error, fd;
-
- /* Get an ready to use file */
- error = -ENFILE;
- file = get_empty_filp();
- if (!file)
- goto eexit_1;
-
- /* Allocates an inode from the eventpoll file system */
- inode = ep_eventpoll_inode();
- if (IS_ERR(inode)) {
- error = PTR_ERR(inode);
- goto eexit_2;
- }
-
- /* Allocates a free descriptor to plug the file onto */
- error = get_unused_fd();
- if (error < 0)
- goto eexit_3;
- fd = error;
-
- /*
- * Link the inode to a directory entry by creating a unique name
- * using the inode number.
- */
- error = -ENOMEM;
- sprintf(name, "[%lu]", inode->i_ino);
- this.name = name;
- this.len = strlen(name);
- this.hash = inode->i_ino;
- dentry = d_alloc(eventpoll_mnt->mnt_sb->s_root, &this);
- if (!dentry)
- goto eexit_4;
- dentry->d_op = &eventpollfs_dentry_operations;
- d_add(dentry, inode);
- file->f_path.mnt = mntget(eventpoll_mnt);
- file->f_path.dentry = dentry;
- file->f_mapping = inode->i_mapping;
-
- file->f_pos = 0;
- file->f_flags = O_RDONLY;
- file->f_op = &eventpoll_fops;
- file->f_mode = FMODE_READ;
- file->f_version = 0;
- file->private_data = ep;
-
- /* Install the new setup file into the allocated fd. */
- fd_install(fd, file);
-
- *efd = fd;
- *einode = inode;
- *efile = file;
- return 0;
-
-eexit_4:
- put_unused_fd(fd);
-eexit_3:
- iput(inode);
-eexit_2:
- put_filp(file);
-eexit_1:
- return error;
-}
-
-
static int ep_alloc(struct eventpoll **pep)
{
struct eventpoll *ep = kzalloc(sizeof(*ep), GFP_KERNEL);
@@ -1553,54 +1452,8 @@
}


-static int eventpollfs_delete_dentry(struct dentry *dentry)
-{
-
- return 1;
-}
-
-
-static struct inode *ep_eventpoll_inode(void)
-{
- int error = -ENOMEM;
- struct inode *inode = new_inode(eventpoll_mnt->mnt_sb);
-
- if (!inode)
- goto eexit_1;
-
- inode->i_fop = &eventpoll_fops;
-
- /*
- * Mark the inode dirty from the very beginning,
- * that way it will never be moved to the dirty
- * list because mark_inode_dirty() will think
- * that it already _is_ on the dirty list.
- */
- inode->i_state = I_DIRTY;
- inode->i_mode = S_IRUSR | S_IWUSR;
- inode->i_uid = current->fsuid;
- inode->i_gid = current->fsgid;
- inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
- return inode;
-
-eexit_1:
- return ERR_PTR(error);
-}
-
-
-static int
-eventpollfs_get_sb(struct file_system_type *fs_type, int flags,
- const char *dev_name, void *data, struct vfsmount *mnt)
-{
- return get_sb_pseudo(fs_type, "eventpoll:", NULL, EVENTPOLLFS_MAGIC,
- mnt);
-}
-
-
static int __init eventpoll_init(void)
{
- int error;
-
mutex_init(&epmutex);

/* Initialize the structure used to perform safe poll wait head wake ups */
@@ -1616,34 +1469,13 @@
sizeof(struct eppoll_entry), 0,
EPI_SLAB_DEBUG|SLAB_PANIC, NULL, NULL);

- /*
- * Register the virtual file system that will be the source of inodes
- * for the eventpoll files
- */
- error = register_filesystem(&eventpoll_fs_type);
- if (error)
- goto epanic;
-
- /* Mount the above commented virtual file system */
- eventpoll_mnt = kern_mount(&eventpoll_fs_type);
- error = PTR_ERR(eventpoll_mnt);
- if (IS_ERR(eventpoll_mnt))
- goto epanic;
-
- DNPRINTK(3, (KERN_INFO "[%p] eventpoll: successfully initialized.\n",
- current));
return 0;
-
-epanic:
- panic("eventpoll_init() failed\n");
}


static void __exit eventpoll_exit(void)
{
/* Undo all operations done inside eventpoll_init() */
- unregister_filesystem(&eventpoll_fs_type);
- mntput(eventpoll_mnt);
kmem_cache_destroy(pwq_cache);
kmem_cache_destroy(epi_cache);
}
-
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