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authorOleg Nesterov <oleg@tv-sign.ru>2007-10-16 23:27:22 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-10-17 08:42:53 -0700
commit0840a90d943bcde2fbfeabd3c256236eed2273cd (patch)
treed423a5b7576f6ba35494aac06c97c6c21dac9bcf
parent2b47c3611de05c585e2d81204f6c7e3e255a3461 (diff)
downloadop-kernel-dev-0840a90d943bcde2fbfeabd3c256236eed2273cd.zip
op-kernel-dev-0840a90d943bcde2fbfeabd3c256236eed2273cd.tar.gz
exec: simplify ->sighand switching
There is no any reason to do recalc_sigpending() after changing ->sighand. To begin with, recalc_sigpending() does not take ->sighand into account. This means we don't need to take newsighand->siglock while changing sighands. rcu_assign_pointer() provides a necessary barrier, and if another process reads the new ->sighand it should either take tasklist_lock or it should use lock_task_sighand() which has a corresponding smp_read_barrier_depends(). Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/exec.c8
1 files changed, 1 insertions, 7 deletions
diff --git a/fs/exec.c b/fs/exec.c
index 59c0038..7f325df 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -916,12 +916,7 @@ no_thread_group:
write_lock_irq(&tasklist_lock);
spin_lock(&oldsighand->siglock);
- spin_lock_nested(&newsighand->siglock, SINGLE_DEPTH_NESTING);
-
rcu_assign_pointer(tsk->sighand, newsighand);
- recalc_sigpending();
-
- spin_unlock(&newsighand->siglock);
spin_unlock(&oldsighand->siglock);
write_unlock_irq(&tasklist_lock);
@@ -931,12 +926,11 @@ no_thread_group:
BUG_ON(!thread_group_leader(tsk));
return 0;
}
-
+
/*
* These functions flushes out all traces of the currently running executable
* so that a new one can be started
*/
-
static void flush_old_files(struct files_struct * files)
{
long j = -1;
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