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authorDavidlohr Bueso <davidlohr.bueso@hp.com>2013-09-12 01:26:18 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2013-09-12 02:59:39 +0400
commit68eccc1dc345539d589ae78ee43b835c1a06a134 (patch)
tree16943d2674537a5d13a14794763a3df7e51411ab /ipc
parent3b1c4ad37741e53804ffe0a30dd01e08b2ab6241 (diff)
downloadlinux-68eccc1dc345539d589ae78ee43b835c1a06a134.tar.xz
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@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>
Diffstat (limited to 'ipc')
-rw-r--r--ipc/shm.c57
1 files changed, 39 insertions, 18 deletions
diff --git a/ipc/shm.c b/ipc/shm.c
index 22cffd78dbb1..3e123987f054 100644
--- a/ipc/shm.c
+++ b/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, cmd, struct shmid_ds __user *, buf)
{
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, cmd, struct shmid_ds __user *, buf)
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:
{