Commit 0840a90d943bcde2fbfeabd3c256236eed2273cd
Committed by
Linus Torvalds
Linus Torvalds
1 parent
2b47c3611d
Exists in
master
and in
4 other branches
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>
Showing 1 changed file with 1 additions and 7 deletions Side-by-side Diff
fs/exec.c
| ... | ... | @@ -916,12 +916,7 @@ |
| 916 | 916 | |
| 917 | 917 | write_lock_irq(&tasklist_lock); |
| 918 | 918 | spin_lock(&oldsighand->siglock); |
| 919 | - spin_lock_nested(&newsighand->siglock, SINGLE_DEPTH_NESTING); | |
| 920 | - | |
| 921 | 919 | rcu_assign_pointer(tsk->sighand, newsighand); |
| 922 | - recalc_sigpending(); | |
| 923 | - | |
| 924 | - spin_unlock(&newsighand->siglock); | |
| 925 | 920 | spin_unlock(&oldsighand->siglock); |
| 926 | 921 | write_unlock_irq(&tasklist_lock); |
| 927 | 922 | |
| 928 | 923 | |
| ... | ... | @@ -931,12 +926,11 @@ |
| 931 | 926 | BUG_ON(!thread_group_leader(tsk)); |
| 932 | 927 | return 0; |
| 933 | 928 | } |
| 934 | - | |
| 929 | + | |
| 935 | 930 | /* |
| 936 | 931 | * These functions flushes out all traces of the currently running executable |
| 937 | 932 | * so that a new one can be started |
| 938 | 933 | */ |
| 939 | - | |
| 940 | 934 | static void flush_old_files(struct files_struct * files) |
| 941 | 935 | { |
| 942 | 936 | long j = -1; |