Subject: + ipcshm-introduce-shmctl_nolock.patch added to -mm tree To: davidlohr.bueso@xxxxxx,manfred@xxxxxxxxxxxxxxxx,riel@xxxxxxxxxx,sedat.dilek@xxxxxxxxx From: akpm@xxxxxxxxxxxxxxxxxxxx Date: Tue, 16 Jul 2013 15:51:47 -0700 The patch titled Subject: ipc,shm: introduce shmctl_nolock has been added to the -mm tree. Its filename is ipcshm-introduce-shmctl_nolock.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/ipcshm-introduce-shmctl_nolock.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/ipcshm-introduce-shmctl_nolock.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 *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: Davidlohr Bueso <davidlohr.bueso@xxxxxx> Subject: ipc,shm: introduce shmctl_nolock Similar to semctl and msgctl, when calling msgctl, the *_INFO and *_STAT commands can be performed without acquiring the ipc object. Add a shmctl_nolock() function and move the logic of *_INFO and *_STAT out of msgctl(). Since we are just moving functionality, this change still takes the lock and it will be properly lockless in the next patch. Signed-off-by: Davidlohr Bueso <davidlohr.bueso@xxxxxx> Tested-by: Sedat Dilek <sedat.dilek@xxxxxxxxx> Cc: Rik van Riel <riel@xxxxxxxxxx> Cc: Manfred Spraul <manfred@xxxxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- ipc/shm.c | 57 +++++++++++++++++++++++++++++++++++----------------- 1 file changed, 39 insertions(+), 18 deletions(-) diff -puN ipc/shm.c~ipcshm-introduce-shmctl_nolock ipc/shm.c --- a/ipc/shm.c~ipcshm-introduce-shmctl_nolock +++ a/ipc/shm.c @@ -820,29 +820,24 @@ out_up: return err; } -SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf) +static int shmctl_nolock(struct ipc_namespace *ns, int shmid, + int cmd, int version, void __user *buf) { + int err; struct shmid_kernel *shp; - int err, version; - struct ipc_namespace *ns; - if (cmd < 0 || shmid < 0) { - err = -EINVAL; - goto out; + /* preliminary security checks for *_INFO */ + if (cmd == IPC_INFO || cmd == SHM_INFO) { + err = security_shm_shmctl(NULL, cmd); + if (err) + return err; } - version = ipc_parse_version(&cmd); - ns = current->nsproxy->ipc_ns; - - switch (cmd) { /* replace with proc interface ? */ + switch (cmd) { case IPC_INFO: { struct shminfo64 shminfo; - err = security_shm_shmctl(NULL, cmd); - if (err) - return err; - memset(&shminfo, 0, sizeof(shminfo)); shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni; shminfo.shmmax = ns->shm_ctlmax; @@ -864,10 +859,6 @@ SYSCALL_DEFINE3(shmctl, int, shmid, int, { struct shm_info shm_info; - err = security_shm_shmctl(NULL, cmd); - if (err) - return err; - memset(&shm_info, 0, sizeof(shm_info)); down_read(&shm_ids(ns).rw_mutex); shm_info.used_ids = shm_ids(ns).in_use; @@ -928,6 +919,36 @@ SYSCALL_DEFINE3(shmctl, int, shmid, int, err = result; goto out; } + default: + return -EINVAL; + } + +out_unlock: + shm_unlock(shp); +out: + return err; +} + +SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf) +{ + struct shmid_kernel *shp; + int err, version; + struct ipc_namespace *ns; + + if (cmd < 0 || shmid < 0) { + err = -EINVAL; + goto out; + } + + version = ipc_parse_version(&cmd); + ns = current->nsproxy->ipc_ns; + + switch (cmd) { + case IPC_INFO: + case SHM_INFO: + case SHM_STAT: + case IPC_STAT: + return shmctl_nolock(ns, shmid, cmd, version, buf); case SHM_LOCK: case SHM_UNLOCK: { _ Patches currently in -mm which might be from davidlohr.bueso@xxxxxx are linux-next.patch ipcshm-introduce-lockless-functions-to-obtain-the-ipc-object.patch ipcshm-shorten-critical-region-in-shmctl_down.patch ipc-drop-ipcctl_pre_down.patch ipc-drop-ipcctl_pre_down-fix.patch ipcshm-introduce-shmctl_nolock.patch ipcshm-make-shmctl_nolock-lockless.patch ipcshm-shorten-critical-region-for-shmctl.patch ipcshm-cleanup-do_shmat-pasta.patch ipcshm-shorten-critical-region-for-shmat.patch ipc-rename-ids-rw_mutex.patch ipcmsg-drop-msg_unlock.patch ipc-document-general-ipc-locking-scheme.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