linux/ipc
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 ipc: introduce shm_rmid_forced sysctl 2011-07-26 16:49:44 -07:00
ipcns_notifier.c
Makefile
mq_sysctl.c
mqueue.c ipc/mqueue.c: fix mq_open() return value 2011-07-26 16:49:44 -07:00
msg.c
msgutil.c
namespace.c
sem.c ipc/sem.c: fix race with concurrent semtimedop() timeouts and IPC_RMID 2011-07-25 20:57:07 -07:00
shm.c shm: optimize locking and ipc_namespace getting 2011-07-30 08:44:20 -10:00
syscall.c
util.c
util.h