Vasiliy Kulikov 4c677e2eef shm: optimize locking and ipc_namespace getting ... shm_lock() does a lookup of shm segment in shm_ids(ns).ipcs_idr, which is redundant as we already know shmid_kernel address. An actual lock is also not required for reads until we really want to destroy the segment. exit_shm() and shm_destroy_orphaned() may avoid the loop by checking whether there is at least one segment in current ipc_namespace. The check of nsproxy and ipc_ns against NULL is redundant as exit_shm() is called from do_exit() before the call to exit_notify(), so the dereferencing current->nsproxy->ipc_ns is guaranteed to be safe. Reported-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Vasiliy Kulikov <segoon@openwall.com> Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2011-07-30 08:44:20 -10:00
..
compat_mq.c
compat.c
ipc_sysctl.c
ipcns_notifier.c
Makefile
mq_sysctl.c
mqueue.c
msg.c
msgutil.c
namespace.c
sem.c
shm.c
syscall.c
util.c
util.h