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Subject[ 40/50] ipc: rename ids->rw_mutex
Date
3.11-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Davidlohr Bueso <davidlohr.bueso@hp.com>

commit d9a605e40b1376eb02b067d7690580255a0df68f upstream.

Since in some situations the lock can be shared for readers, we shouldn't
be calling it a mutex, rename it to rwsem.

Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
include/linux/ipc_namespace.h | 2 -
ipc/msg.c | 20 +++++++--------
ipc/namespace.c | 4 +--
ipc/sem.c | 24 +++++++++---------
ipc/shm.c | 56 +++++++++++++++++++++---------------------
ipc/util.c | 28 ++++++++++-----------
ipc/util.h | 4 +--
7 files changed, 69 insertions(+), 69 deletions(-)

--- a/include/linux/ipc_namespace.h
+++ b/include/linux/ipc_namespace.h
@@ -22,7 +22,7 @@ struct ipc_ids {
int in_use;
unsigned short seq;
unsigned short seq_max;
- struct rw_semaphore rw_mutex;
+ struct rw_semaphore rwsem;
struct idr ipcs_idr;
int next_id;
};
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -181,7 +181,7 @@ static void msg_rcu_free(struct rcu_head
* @ns: namespace
* @params: ptr to the structure that contains the key and msgflg
*
- * Called with msg_ids.rw_mutex held (writer)
+ * Called with msg_ids.rwsem held (writer)
*/
static int newque(struct ipc_namespace *ns, struct ipc_params *params)
{
@@ -267,8 +267,8 @@ static void expunge_all(struct msg_queue
* removes the message queue from message queue ID IDR, and cleans up all the
* messages associated with this queue.
*
- * msg_ids.rw_mutex (writer) and the spinlock for this message queue are held
- * before freeque() is called. msg_ids.rw_mutex remains locked on exit.
+ * msg_ids.rwsem (writer) and the spinlock for this message queue are held
+ * before freeque() is called. msg_ids.rwsem remains locked on exit.
*/
static void freeque(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
{
@@ -289,7 +289,7 @@ static void freeque(struct ipc_namespace
}

/*
- * Called with msg_ids.rw_mutex and ipcp locked.
+ * Called with msg_ids.rwsem and ipcp locked.
*/
static inline int msg_security(struct kern_ipc_perm *ipcp, int msgflg)
{
@@ -393,9 +393,9 @@ copy_msqid_from_user(struct msqid64_ds *
}

/*
- * This function handles some msgctl commands which require the rw_mutex
+ * This function handles some msgctl commands which require the rwsem
* to be held in write mode.
- * NOTE: no locks must be held, the rw_mutex is taken inside this function.
+ * NOTE: no locks must be held, the rwsem is taken inside this function.
*/
static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd,
struct msqid_ds __user *buf, int version)
@@ -410,7 +410,7 @@ static int msgctl_down(struct ipc_namesp
return -EFAULT;
}

- down_write(&msg_ids(ns).rw_mutex);
+ down_write(&msg_ids(ns).rwsem);
rcu_read_lock();

ipcp = ipcctl_pre_down_nolock(ns, &msg_ids(ns), msqid, cmd,
@@ -466,7 +466,7 @@ out_unlock0:
out_unlock1:
rcu_read_unlock();
out_up:
- up_write(&msg_ids(ns).rw_mutex);
+ up_write(&msg_ids(ns).rwsem);
return err;
}

@@ -501,7 +501,7 @@ static int msgctl_nolock(struct ipc_name
msginfo.msgmnb = ns->msg_ctlmnb;
msginfo.msgssz = MSGSSZ;
msginfo.msgseg = MSGSEG;
- down_read(&msg_ids(ns).rw_mutex);
+ down_read(&msg_ids(ns).rwsem);
if (cmd == MSG_INFO) {
msginfo.msgpool = msg_ids(ns).in_use;
msginfo.msgmap = atomic_read(&ns->msg_hdrs);
@@ -512,7 +512,7 @@ static int msgctl_nolock(struct ipc_name
msginfo.msgtql = MSGTQL;
}
max_id = ipc_get_maxid(&msg_ids(ns));
- up_read(&msg_ids(ns).rw_mutex);
+ up_read(&msg_ids(ns).rwsem);
if (copy_to_user(buf, &msginfo, sizeof(struct msginfo)))
return -EFAULT;
return (max_id < 0) ? 0 : max_id;
--- a/ipc/namespace.c
+++ b/ipc/namespace.c
@@ -81,7 +81,7 @@ void free_ipcs(struct ipc_namespace *ns,
int next_id;
int total, in_use;

- down_write(&ids->rw_mutex);
+ down_write(&ids->rwsem);

in_use = ids->in_use;

@@ -93,7 +93,7 @@ void free_ipcs(struct ipc_namespace *ns,
free(ns, perm);
total++;
}
- up_write(&ids->rw_mutex);
+ up_write(&ids->rwsem);
}

static void free_ipc_ns(struct ipc_namespace *ns)
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -365,7 +365,7 @@ static inline void sem_unlock(struct sem
}

/*
- * sem_lock_(check_) routines are called in the paths where the rw_mutex
+ * sem_lock_(check_) routines are called in the paths where the rwsem
* is not held.
*
* The caller holds the RCU read lock.
@@ -464,7 +464,7 @@ static inline void sem_rmid(struct ipc_n
* @ns: namespace
* @params: ptr to the structure that contains key, semflg and nsems
*
- * Called with sem_ids.rw_mutex held (as a writer)
+ * Called with sem_ids.rwsem held (as a writer)
*/

static int newary(struct ipc_namespace *ns, struct ipc_params *params)
@@ -529,7 +529,7 @@ static int newary(struct ipc_namespace *


/*
- * Called with sem_ids.rw_mutex and ipcp locked.
+ * Called with sem_ids.rwsem and ipcp locked.
*/
static inline int sem_security(struct kern_ipc_perm *ipcp, int semflg)
{
@@ -540,7 +540,7 @@ static inline int sem_security(struct ke
}

/*
- * Called with sem_ids.rw_mutex and ipcp locked.
+ * Called with sem_ids.rwsem and ipcp locked.
*/
static inline int sem_more_checks(struct kern_ipc_perm *ipcp,
struct ipc_params *params)
@@ -1031,8 +1031,8 @@ static int count_semzcnt (struct sem_arr
return semzcnt;
}

-/* Free a semaphore set. freeary() is called with sem_ids.rw_mutex locked
- * as a writer and the spinlock for this semaphore set hold. sem_ids.rw_mutex
+/* Free a semaphore set. freeary() is called with sem_ids.rwsem locked
+ * as a writer and the spinlock for this semaphore set hold. sem_ids.rwsem
* remains locked on exit.
*/
static void freeary(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
@@ -1152,7 +1152,7 @@ static int semctl_nolock(struct ipc_name
seminfo.semmnu = SEMMNU;
seminfo.semmap = SEMMAP;
seminfo.semume = SEMUME;
- down_read(&sem_ids(ns).rw_mutex);
+ down_read(&sem_ids(ns).rwsem);
if (cmd == SEM_INFO) {
seminfo.semusz = sem_ids(ns).in_use;
seminfo.semaem = ns->used_sems;
@@ -1161,7 +1161,7 @@ static int semctl_nolock(struct ipc_name
seminfo.semaem = SEMAEM;
}
max_id = ipc_get_maxid(&sem_ids(ns));
- up_read(&sem_ids(ns).rw_mutex);
+ up_read(&sem_ids(ns).rwsem);
if (copy_to_user(p, &seminfo, sizeof(struct seminfo)))
return -EFAULT;
return (max_id < 0) ? 0: max_id;
@@ -1467,9 +1467,9 @@ copy_semid_from_user(struct semid64_ds *
}

/*
- * This function handles some semctl commands which require the rw_mutex
+ * This function handles some semctl commands which require the rwsem
* to be held in write mode.
- * NOTE: no locks must be held, the rw_mutex is taken inside this function.
+ * NOTE: no locks must be held, the rwsem is taken inside this function.
*/
static int semctl_down(struct ipc_namespace *ns, int semid,
int cmd, int version, void __user *p)
@@ -1484,7 +1484,7 @@ static int semctl_down(struct ipc_namesp
return -EFAULT;
}

- down_write(&sem_ids(ns).rw_mutex);
+ down_write(&sem_ids(ns).rwsem);
rcu_read_lock();

ipcp = ipcctl_pre_down_nolock(ns, &sem_ids(ns), semid, cmd,
@@ -1523,7 +1523,7 @@ out_unlock0:
out_unlock1:
rcu_read_unlock();
out_up:
- up_write(&sem_ids(ns).rw_mutex);
+ up_write(&sem_ids(ns).rwsem);
return err;
}

--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -83,8 +83,8 @@ void shm_init_ns(struct ipc_namespace *n
}

/*
- * Called with shm_ids.rw_mutex (writer) and the shp structure locked.
- * Only shm_ids.rw_mutex remains locked on exit.
+ * Called with shm_ids.rwsem (writer) and the shp structure locked.
+ * Only shm_ids.rwsem remains locked on exit.
*/
static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
{
@@ -148,7 +148,7 @@ static inline struct shmid_kernel *shm_o
}

/*
- * shm_lock_(check_) routines are called in the paths where the rw_mutex
+ * shm_lock_(check_) routines are called in the paths where the rwsem
* is not necessarily held.
*/
static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
@@ -214,7 +214,7 @@ static void shm_open(struct vm_area_stru
* @ns: namespace
* @shp: struct to free
*
- * It has to be called with shp and shm_ids.rw_mutex (writer) locked,
+ * It has to be called with shp and shm_ids.rwsem (writer) locked,
* but returns with shp unlocked and freed.
*/
static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
@@ -261,7 +261,7 @@ static void shm_close(struct vm_area_str
struct shmid_kernel *shp;
struct ipc_namespace *ns = sfd->ns;

- down_write(&shm_ids(ns).rw_mutex);
+ down_write(&shm_ids(ns).rwsem);
/* remove from the list of attaches of the shm segment */
shp = shm_lock(ns, sfd->id);
BUG_ON(IS_ERR(shp));
@@ -272,10 +272,10 @@ static void shm_close(struct vm_area_str
shm_destroy(ns, shp);
else
shm_unlock(shp);
- up_write(&shm_ids(ns).rw_mutex);
+ up_write(&shm_ids(ns).rwsem);
}

-/* Called with ns->shm_ids(ns).rw_mutex locked */
+/* Called with ns->shm_ids(ns).rwsem locked */
static int shm_try_destroy_current(int id, void *p, void *data)
{
struct ipc_namespace *ns = data;
@@ -306,7 +306,7 @@ static int shm_try_destroy_current(int i
return 0;
}

-/* Called with ns->shm_ids(ns).rw_mutex locked */
+/* Called with ns->shm_ids(ns).rwsem locked */
static int shm_try_destroy_orphaned(int id, void *p, void *data)
{
struct ipc_namespace *ns = data;
@@ -317,7 +317,7 @@ static int shm_try_destroy_orphaned(int
* We want to destroy segments without users and with already
* exit'ed originating process.
*
- * As shp->* are changed under rw_mutex, it's safe to skip shp locking.
+ * As shp->* are changed under rwsem, it's safe to skip shp locking.
*/
if (shp->shm_creator != NULL)
return 0;
@@ -331,10 +331,10 @@ static int shm_try_destroy_orphaned(int

void shm_destroy_orphaned(struct ipc_namespace *ns)
{
- down_write(&shm_ids(ns).rw_mutex);
+ down_write(&shm_ids(ns).rwsem);
if (shm_ids(ns).in_use)
idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_orphaned, ns);
- up_write(&shm_ids(ns).rw_mutex);
+ up_write(&shm_ids(ns).rwsem);
}


@@ -346,10 +346,10 @@ void exit_shm(struct task_struct *task)
return;

/* Destroy all already created segments, but not mapped yet */
- down_write(&shm_ids(ns).rw_mutex);
+ down_write(&shm_ids(ns).rwsem);
if (shm_ids(ns).in_use)
idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_current, ns);
- up_write(&shm_ids(ns).rw_mutex);
+ up_write(&shm_ids(ns).rwsem);
}

static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
@@ -483,7 +483,7 @@ static const struct vm_operations_struct
* @ns: namespace
* @params: ptr to the structure that contains key, size and shmflg
*
- * Called with shm_ids.rw_mutex held as a writer.
+ * Called with shm_ids.rwsem held as a writer.
*/

static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
@@ -590,7 +590,7 @@ no_file:
}

/*
- * Called with shm_ids.rw_mutex and ipcp locked.
+ * Called with shm_ids.rwsem and ipcp locked.
*/
static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
{
@@ -601,7 +601,7 @@ static inline int shm_security(struct ke
}

/*
- * Called with shm_ids.rw_mutex and ipcp locked.
+ * Called with shm_ids.rwsem and ipcp locked.
*/
static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
struct ipc_params *params)
@@ -714,7 +714,7 @@ static inline unsigned long copy_shminfo

/*
* Calculate and add used RSS and swap pages of a shm.
- * Called with shm_ids.rw_mutex held as a reader
+ * Called with shm_ids.rwsem held as a reader
*/
static void shm_add_rss_swap(struct shmid_kernel *shp,
unsigned long *rss_add, unsigned long *swp_add)
@@ -741,7 +741,7 @@ static void shm_add_rss_swap(struct shmi
}

/*
- * Called with shm_ids.rw_mutex held as a reader
+ * Called with shm_ids.rwsem held as a reader
*/
static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
unsigned long *swp)
@@ -770,9 +770,9 @@ static void shm_get_stat(struct ipc_name
}

/*
- * This function handles some shmctl commands which require the rw_mutex
+ * This function handles some shmctl commands which require the rwsem
* to be held in write mode.
- * NOTE: no locks must be held, the rw_mutex is taken inside this function.
+ * NOTE: no locks must be held, the rwsem is taken inside this function.
*/
static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
struct shmid_ds __user *buf, int version)
@@ -787,7 +787,7 @@ static int shmctl_down(struct ipc_namesp
return -EFAULT;
}

- down_write(&shm_ids(ns).rw_mutex);
+ down_write(&shm_ids(ns).rwsem);
rcu_read_lock();

ipcp = ipcctl_pre_down_nolock(ns, &shm_ids(ns), shmid, cmd,
@@ -826,7 +826,7 @@ out_unlock0:
out_unlock1:
rcu_read_unlock();
out_up:
- up_write(&shm_ids(ns).rw_mutex);
+ up_write(&shm_ids(ns).rwsem);
return err;
}

@@ -857,9 +857,9 @@ static int shmctl_nolock(struct ipc_name
if(copy_shminfo_to_user (buf, &shminfo, version))
return -EFAULT;

- down_read(&shm_ids(ns).rw_mutex);
+ down_read(&shm_ids(ns).rwsem);
err = ipc_get_maxid(&shm_ids(ns));
- up_read(&shm_ids(ns).rw_mutex);
+ up_read(&shm_ids(ns).rwsem);

if(err<0)
err = 0;
@@ -870,14 +870,14 @@ static int shmctl_nolock(struct ipc_name
struct shm_info shm_info;

memset(&shm_info, 0, sizeof(shm_info));
- down_read(&shm_ids(ns).rw_mutex);
+ down_read(&shm_ids(ns).rwsem);
shm_info.used_ids = shm_ids(ns).in_use;
shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
shm_info.shm_tot = ns->shm_tot;
shm_info.swap_attempts = 0;
shm_info.swap_successes = 0;
err = ipc_get_maxid(&shm_ids(ns));
- up_read(&shm_ids(ns).rw_mutex);
+ up_read(&shm_ids(ns).rwsem);
if (copy_to_user(buf, &shm_info, sizeof(shm_info))) {
err = -EFAULT;
goto out;
@@ -1176,7 +1176,7 @@ out_fput:
fput(file);

out_nattch:
- down_write(&shm_ids(ns).rw_mutex);
+ down_write(&shm_ids(ns).rwsem);
shp = shm_lock(ns, shmid);
BUG_ON(IS_ERR(shp));
shp->shm_nattch--;
@@ -1184,7 +1184,7 @@ out_nattch:
shm_destroy(ns, shp);
else
shm_unlock(shp);
- up_write(&shm_ids(ns).rw_mutex);
+ up_write(&shm_ids(ns).rwsem);
return err;

out_unlock:
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -119,7 +119,7 @@ __initcall(ipc_init);

void ipc_init_ids(struct ipc_ids *ids)
{
- init_rwsem(&ids->rw_mutex);
+ init_rwsem(&ids->rwsem);

ids->in_use = 0;
ids->seq = 0;
@@ -174,7 +174,7 @@ void __init ipc_init_proc_interface(cons
* @ids: Identifier set
* @key: The key to find
*
- * Requires ipc_ids.rw_mutex locked.
+ * Requires ipc_ids.rwsem locked.
* Returns the LOCKED pointer to the ipc structure if found or NULL
* if not.
* If key is found ipc points to the owning ipc structure
@@ -208,7 +208,7 @@ static struct kern_ipc_perm *ipc_findkey
* ipc_get_maxid - get the last assigned id
* @ids: IPC identifier set
*
- * Called with ipc_ids.rw_mutex held.
+ * Called with ipc_ids.rwsem held.
*/

int ipc_get_maxid(struct ipc_ids *ids)
@@ -246,7 +246,7 @@ int ipc_get_maxid(struct ipc_ids *ids)
* is returned. The 'new' entry is returned in a locked state on success.
* On failure the entry is not locked and a negative err-code is returned.
*
- * Called with writer ipc_ids.rw_mutex held.
+ * Called with writer ipc_ids.rwsem held.
*/
int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size)
{
@@ -312,9 +312,9 @@ static int ipcget_new(struct ipc_namespa
{
int err;

- down_write(&ids->rw_mutex);
+ down_write(&ids->rwsem);
err = ops->getnew(ns, params);
- up_write(&ids->rw_mutex);
+ up_write(&ids->rwsem);
return err;
}

@@ -331,7 +331,7 @@ static int ipcget_new(struct ipc_namespa
*
* On success, the IPC id is returned.
*
- * It is called with ipc_ids.rw_mutex and ipcp->lock held.
+ * It is called with ipc_ids.rwsem and ipcp->lock held.
*/
static int ipc_check_perms(struct ipc_namespace *ns,
struct kern_ipc_perm *ipcp,
@@ -376,7 +376,7 @@ static int ipcget_public(struct ipc_name
* Take the lock as a writer since we are potentially going to add
* a new entry + read locks are not "upgradable"
*/
- down_write(&ids->rw_mutex);
+ down_write(&ids->rwsem);
ipcp = ipc_findkey(ids, params->key);
if (ipcp == NULL) {
/* key not used */
@@ -402,7 +402,7 @@ static int ipcget_public(struct ipc_name
}
ipc_unlock(ipcp);
}
- up_write(&ids->rw_mutex);
+ up_write(&ids->rwsem);

return err;
}
@@ -413,7 +413,7 @@ static int ipcget_public(struct ipc_name
* @ids: IPC identifier set
* @ipcp: ipc perm structure containing the identifier to remove
*
- * ipc_ids.rw_mutex (as a writer) and the spinlock for this ID are held
+ * ipc_ids.rwsem (as a writer) and the spinlock for this ID are held
* before this function is called, and remain locked on the exit.
*/

@@ -613,7 +613,7 @@ struct kern_ipc_perm *ipc_obtain_object(
}

/**
- * ipc_lock - Lock an ipc structure without rw_mutex held
+ * ipc_lock - Lock an ipc structure without rwsem held
* @ids: IPC identifier set
* @id: ipc id to look for
*
@@ -740,7 +740,7 @@ int ipc_update_perm(struct ipc64_perm *i
* - performs some audit and permission check, depending on the given cmd
* - returns a pointer to the ipc object or otherwise, the corresponding error.
*
- * Call holding the both the rw_mutex and the rcu read lock.
+ * Call holding the both the rwsem and the rcu read lock.
*/
struct kern_ipc_perm *ipcctl_pre_down_nolock(struct ipc_namespace *ns,
struct ipc_ids *ids, int id, int cmd,
@@ -860,7 +860,7 @@ static void *sysvipc_proc_start(struct s
* Take the lock - this will be released by the corresponding
* call to stop().
*/
- down_read(&ids->rw_mutex);
+ down_read(&ids->rwsem);

/* pos < 0 is invalid */
if (*pos < 0)
@@ -887,7 +887,7 @@ static void sysvipc_proc_stop(struct seq

ids = &iter->ns->ids[iface->ids];
/* Release the lock we took in start() */
- up_read(&ids->rw_mutex);
+ up_read(&ids->rwsem);
}

static int sysvipc_proc_show(struct seq_file *s, void *it)
--- a/ipc/util.h
+++ b/ipc/util.h
@@ -101,10 +101,10 @@ void __init ipc_init_proc_interface(cons
#define ipcid_to_idx(id) ((id) % SEQ_MULTIPLIER)
#define ipcid_to_seqx(id) ((id) / SEQ_MULTIPLIER)

-/* must be called with ids->rw_mutex acquired for writing */
+/* must be called with ids->rwsem acquired for writing */
int ipc_addid(struct ipc_ids *, struct kern_ipc_perm *, int);

-/* must be called with ids->rw_mutex acquired for reading */
+/* must be called with ids->rwsem acquired for reading */
int ipc_get_maxid(struct ipc_ids *);

/* must be called with both locks acquired. */



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