The patch titled IPC/semaphores: move the rwmutex handling inside semctl_down has been added to the -mm tree. Its filename is ipc-semaphores-move-the-rwmutex-handling-inside-semctl_down.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find out what to do about this The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/ ------------------------------------------------------ Subject: IPC/semaphores: move the rwmutex handling inside semctl_down From: Pierre Peiffer <pierre.peiffer@xxxxxxxx> semctl_down is called with the rwmutex (the one which protects the list of ipcs) taken in write mode. This patch moves this rwmutex taken in write-mode inside semctl_down. This has the advantages of reducing a little bit the window during which this rwmutex is taken, clarifying sys_semctl, and finally of having a coherent behaviour with [shm|msg]ctl_down Signed-off-by: Pierre Peiffer <pierre.peiffer@xxxxxxxx> Acked-by: Serge Hallyn <serue@xxxxxxxxxx> Cc: Nadia Derbey <Nadia.Derbey@xxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- ipc/sem.c | 24 +++++++++++++----------- 1 file changed, 13 insertions(+), 11 deletions(-) diff -puN ipc/sem.c~ipc-semaphores-move-the-rwmutex-handling-inside-semctl_down ipc/sem.c --- a/ipc/sem.c~ipc-semaphores-move-the-rwmutex-handling-inside-semctl_down +++ a/ipc/sem.c @@ -875,6 +875,11 @@ static inline unsigned long copy_semid_f } } +/* + * This function handles some semctl commands which require the rw_mutex + * to be held in write mode. + * NOTE: no locks must be held, the rw_mutex is taken inside this function. + */ static int semctl_down(struct ipc_namespace *ns, int semid, int semnum, int cmd, int version, union semun arg) { @@ -887,9 +892,12 @@ static int semctl_down(struct ipc_namesp if(copy_semid_from_user (&setbuf, arg.buf, version)) return -EFAULT; } + down_write(&sem_ids(ns).rw_mutex); sma = sem_lock_check_down(ns, semid); - if (IS_ERR(sma)) - return PTR_ERR(sma); + if (IS_ERR(sma)) { + err = PTR_ERR(sma); + goto out_up; + } ipcp = &sma->sem_perm; @@ -915,26 +923,22 @@ static int semctl_down(struct ipc_namesp switch(cmd){ case IPC_RMID: freeary(ns, ipcp); - err = 0; - break; + goto out_up; case IPC_SET: ipcp->uid = setbuf.uid; ipcp->gid = setbuf.gid; ipcp->mode = (ipcp->mode & ~S_IRWXUGO) | (setbuf.mode & S_IRWXUGO); sma->sem_ctime = get_seconds(); - sem_unlock(sma); - err = 0; break; default: - sem_unlock(sma); err = -EINVAL; - break; } - return err; out_unlock: sem_unlock(sma); +out_up: + up_write(&sem_ids(ns).rw_mutex); return err; } @@ -968,9 +972,7 @@ asmlinkage long sys_semctl (int semid, i return err; case IPC_RMID: case IPC_SET: - down_write(&sem_ids(ns).rw_mutex); err = semctl_down(ns,semid,semnum,cmd,version,arg); - up_write(&sem_ids(ns).rw_mutex); return err; default: return -EINVAL; _ Patches currently in -mm which might be from pierre.peiffer@xxxxxxxx are origin.patch ipc-use-ipc_buildid-directly-from-ipc_addid.patch ipc-use-ipc_buildid-directly-from-ipc_addid-cleanup.patch ipc-scale-msgmni-to-the-amount-of-lowmem.patch ipc-scale-msgmni-to-the-number-of-ipc-namespaces.patch ipc-define-the-slab_memory_callback-priority-as-a-constant.patch ipc-recompute-msgmni-on-memory-add--remove.patch ipc-invoke-the-ipcns-notifier-chain-as-a-work-item.patch ipc-recompute-msgmni-on-ipc-namespace-creation-removal.patch ipc-do-not-recompute-msgmni-anymore-if-explicitly-set-by-user.patch ipc-re-enable-msgmni-automatic-recomputing-msgmni-if-set-to-negative.patch ipc-semaphores-code-factorisation.patch ipc-shared-memory-introduce-shmctl_down.patch ipc-message-queues-introduce-msgctl_down.patch ipc-semaphores-move-the-rwmutex-handling-inside-semctl_down.patch ipc-semaphores-remove-one-unused-parameter-from-semctl_down.patch ipc-get-rid-of-the-use-_setbuf-structure.patch ipc-introduce-ipc_update_perm.patch ipc-consolidate-all-xxxctl_down-functions.patch - To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html