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ipc: rename ids->rw_mutex 

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>
This commit is contained in:
Davidlohr Bueso 2013-09-11 14:26:24 -07:00 committed by Linus Torvalds
parent c2c737a046
commit d9a605e40b
7 changed files with 69 additions and 69 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/linux/ipc_namespace.h
View File

@ -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;
};

20
ipc/msg.c
View File

@ -172,7 +172,7 @@ static inline void msg_rmid(struct ipc_namespace *ns, struct msg_queue *s)
* @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)
{
@ -259,8 +259,8 @@ static void expunge_all(struct msg_queue *msq, int res)
* 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)
{
@ -282,7 +282,7 @@ static void freeque(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
}
/*
* 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)
{
@ -386,9 +386,9 @@ copy_msqid_from_user(struct msqid64_ds *out, void __user *buf, int version)
}
/*
* 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)
@ -403,7 +403,7 @@ static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd,
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,
@ -459,7 +459,7 @@ out_unlock0:
out_unlock1:
rcu_read_unlock();
out_up:
up_write(&msg_ids(ns).rw_mutex);
up_write(&msg_ids(ns).rwsem);
return err;
}
@ -494,7 +494,7 @@ static int msgctl_nolock(struct ipc_namespace *ns, int msqid,
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);
@ -505,7 +505,7 @@ static int msgctl_nolock(struct ipc_namespace *ns, int msqid,
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;

4
ipc/namespace.c
View File

@ -81,7 +81,7 @@ void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
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, struct ipc_ids *ids,
free(ns, perm);
total++;
}
up_write(&ids->rw_mutex);
up_write(&ids->rwsem);
}
static void free_ipc_ns(struct ipc_namespace *ns)

24
ipc/sem.c
View File

@ -322,7 +322,7 @@ static inline void sem_unlock(struct sem_array *sma, int locknum)
}
/*
* 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.
@ -426,7 +426,7 @@ static inline void sem_rmid(struct ipc_namespace *ns, struct sem_array *s)
* @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)
@ -492,7 +492,7 @@ static int newary(struct ipc_namespace *ns, struct ipc_params *params)
/*
* 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)
{
@ -503,7 +503,7 @@ static inline int sem_security(struct kern_ipc_perm *ipcp, int semflg)
}
/*
* 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)
@ -994,8 +994,8 @@ static int count_semzcnt (struct sem_array * sma, ushort semnum)
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)
@ -1116,7 +1116,7 @@ static int semctl_nolock(struct ipc_namespace *ns, int semid,
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;
@ -1125,7 +1125,7 @@ static int semctl_nolock(struct ipc_namespace *ns, int semid,
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;
@ -1431,9 +1431,9 @@ copy_semid_from_user(struct semid64_ds *out, void __user *buf, int version)
}
/*
* 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)
@ -1448,7 +1448,7 @@ static int semctl_down(struct ipc_namespace *ns, int semid,
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,
@ -1487,7 +1487,7 @@ out_unlock0:
out_unlock1:
rcu_read_unlock();
out_up:
up_write(&sem_ids(ns).rw_mutex);
up_write(&sem_ids(ns).rwsem);
return err;
}

56
ipc/shm.c
View File

@ -83,8 +83,8 @@ void shm_init_ns(struct ipc_namespace *ns)
}
/*
* 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_obtain_object_check(struct ipc_namespace
}
/*
* 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)
@ -205,7 +205,7 @@ static void shm_open(struct vm_area_struct *vma)
* @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)
@ -253,7 +253,7 @@ static void shm_close(struct vm_area_struct *vma)
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));
@ -264,10 +264,10 @@ static void shm_close(struct vm_area_struct *vma)
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;
@ -298,7 +298,7 @@ static int shm_try_destroy_current(int id, void *p, void *data)
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;
@ -309,7 +309,7 @@ static int shm_try_destroy_orphaned(int id, void *p, void *data)
* 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;
@ -323,10 +323,10 @@ static int shm_try_destroy_orphaned(int id, void *p, void *data)
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);
}
@ -338,10 +338,10 @@ 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)
@ -475,7 +475,7 @@ static const struct vm_operations_struct shm_vm_ops = {
* @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)
@ -583,7 +583,7 @@ 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)
{
@ -594,7 +594,7 @@ static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
}
/*
* 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)
@ -707,7 +707,7 @@ static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminf
/*
* 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)
@ -734,7 +734,7 @@ static void shm_add_rss_swap(struct shmid_kernel *shp,
}
/*
* 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)
@ -763,9 +763,9 @@ static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
}
/*
* 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)
@ -780,7 +780,7 @@ static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
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,
@ -819,7 +819,7 @@ out_unlock0:
out_unlock1:
rcu_read_unlock();
out_up:
up_write(&shm_ids(ns).rw_mutex);
up_write(&shm_ids(ns).rwsem);
return err;
}
@ -850,9 +850,9 @@ static int shmctl_nolock(struct ipc_namespace *ns, int shmid,
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;
@ -863,14 +863,14 @@ static int shmctl_nolock(struct ipc_namespace *ns, int shmid,
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;
@ -1169,7 +1169,7 @@ 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--;
@ -1177,7 +1177,7 @@ 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:

28
ipc/util.c
View File

@ -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(const char *path, const char *header,
* @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(struct ipc_ids *ids, key_t key)
* 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_namespace *ns, struct ipc_ids *ids,
{
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_namespace *ns, struct ipc_ids *ids,
*
* 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_namespace *ns, struct ipc_ids *ids,
* 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_namespace *ns, struct ipc_ids *ids,
}
ipc_unlock(ipcp);
}
up_write(&ids->rw_mutex);
up_write(&ids->rwsem);
return err;
}
@ -413,7 +413,7 @@ static int ipcget_public(struct ipc_namespace *ns, struct ipc_ids *ids,
* @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.
*/
@ -621,7 +621,7 @@ struct kern_ipc_perm *ipc_obtain_object(struct ipc_ids *ids, int id)
}
/**
* 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
*
@ -748,7 +748,7 @@ int ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out)
* - 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,
@ -868,7 +868,7 @@ static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos)
* 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)
@ -895,7 +895,7 @@ static void sysvipc_proc_stop(struct seq_file *s, void *it)
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)

4
ipc/util.h
View File

@ -94,10 +94,10 @@ void __init ipc_init_proc_interface(const char *path, const char *header,
#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. */