unimore/kernel-hacking-2024-linux-steffo
unimore/kernel-hacking-2024-linux-steffo
1
Fork 0
Code Pull requests 5 Wiki Activity

[PATCH] do_sigaction: don't take tasklist_lock

Browse source 
do_sigaction() does not need tasklist_lock anymore, we can simplify the code.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Oleg Nesterov 2006-03-28 16:11:24 -08:00 committed by Linus Torvalds
parent aacc90944d
commit 88531f725b
1 changed files with 3 additions and 19 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

22
kernel/signal.c
View file

@ -2301,8 +2301,7 @@ sys_rt_sigqueueinfo(int pid, int sig, siginfo_t __user *uinfo)
return kill_proc_info(sig, &info, pid); return kill_proc_info(sig, &info, pid);
} }
int int do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
{ {
struct k_sigaction *k; struct k_sigaction *k;
sigset_t mask; sigset_t mask;
@ -2328,6 +2327,7 @@ do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
if (act) { if (act) {
sigdelsetmask(&act->sa.sa_mask, sigdelsetmask(&act->sa.sa_mask,
sigmask(SIGKILL) | sigmask(SIGSTOP)); sigmask(SIGKILL) | sigmask(SIGSTOP));
*k = *act;
/* /*
* POSIX 3.3.1.3: * POSIX 3.3.1.3:
* "Setting a signal action to SIG_IGN for a signal that is * "Setting a signal action to SIG_IGN for a signal that is
@ -2340,19 +2340,8 @@ do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
* be discarded, whether or not it is blocked" * be discarded, whether or not it is blocked"
*/ */
if (act->sa.sa_handler == SIG_IGN || if (act->sa.sa_handler == SIG_IGN ||
(act->sa.sa_handler == SIG_DFL && (act->sa.sa_handler == SIG_DFL && sig_kernel_ignore(sig))) {
sig_kernel_ignore(sig))) {
/*
* This is a fairly rare case, so we only take the
* tasklist_lock once we're sure we'll need it.
* Now we must do this little unlock and relock
* dance to maintain the lock hierarchy.
*/
struct task_struct *t = current; struct task_struct *t = current;
spin_unlock_irq(&t->sighand->siglock);
read_lock(&tasklist_lock);
spin_lock_irq(&t->sighand->siglock);
*k = *act;
sigemptyset(&mask); sigemptyset(&mask);
sigaddset(&mask, sig); sigaddset(&mask, sig);
rm_from_queue_full(&mask, &t->signal->shared_pending); rm_from_queue_full(&mask, &t->signal->shared_pending);
@ -2361,12 +2350,7 @@ do_sigaction(int sig, struct k_sigaction *act, struct k_sigaction *oact)
recalc_sigpending_tsk(t); recalc_sigpending_tsk(t);
t = next_thread(t); t = next_thread(t);
} while (t != current); } while (t != current);
spin_unlock_irq(&current->sighand->siglock);
read_unlock(&tasklist_lock);
return 0;
} }
*k = *act;
} }
spin_unlock_irq(&current->sighand->siglock); spin_unlock_irq(&current->sighand->siglock);