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| author | Oleg Nesterov <oleg@redhat.com> | 2011-04-27 19:54:20 +0200 |
|---|---|---|
| committer | Oleg Nesterov <oleg@redhat.com> | 2011-04-28 13:01:36 +0200 |
| commit | 73ef4aeb61b53fce464a7e24ef03a26f98b2f617 (patch) | |
| tree | 15acc5d7ded643ccd1da1d502033822a2452497c /kernel/signal.c | |
| parent | fec9993db093acfc3999a364e31f8adae41fcb28 (diff) | |
| download | linux-73ef4aeb61b53fce464a7e24ef03a26f98b2f617.tar.gz linux-73ef4aeb61b53fce464a7e24ef03a26f98b2f617.tar.bz2 linux-73ef4aeb61b53fce464a7e24ef03a26f98b2f617.zip | |
signal: sigprocmask: narrow the scope of ->siglock
No functional changes, preparation to simplify the review of the next change.
1. We can read current->block lockless, nobody else can ever change this mask.
2. Calculate the resulting sigset_t outside of ->siglock into the temporary
variable, then take ->siglock and change ->blocked.
Also, kill the stale comment about BKL.
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Matt Fleming <matt.fleming@linux.intel.com>
Acked-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel/signal.c')
| -rw-r--r-- | kernel/signal.c | 29 |
1 files changed, 13 insertions, 16 deletions
diff --git a/kernel/signal.c b/kernel/signal.c index 707736e64e0e..e8308e3238c1 100644 --- a/kernel/signal.c +++ b/kernel/signal.c @@ -2300,12 +2300,6 @@ long do_no_restart_syscall(struct restart_block *param) } /* - * We don't need to get the kernel lock - this is all local to this - * particular thread.. (and that's good, because this is _heavily_ - * used by various programs) - */ - -/* * This is also useful for kernel threads that want to temporarily * (or permanently) block certain signals. * @@ -2315,30 +2309,33 @@ long do_no_restart_syscall(struct restart_block *param) */ int sigprocmask(int how, sigset_t *set, sigset_t *oldset) { - int error; + struct task_struct *tsk = current; + sigset_t newset; - spin_lock_irq(¤t->sighand->siglock); + /* Lockless, only current can change ->blocked, never from irq */ if (oldset) - *oldset = current->blocked; + *oldset = tsk->blocked; - error = 0; switch (how) { case SIG_BLOCK: - sigorsets(¤t->blocked, ¤t->blocked, set); + sigorsets(&newset, &tsk->blocked, set); break; case SIG_UNBLOCK: - signandsets(¤t->blocked, ¤t->blocked, set); + signandsets(&newset, &tsk->blocked, set); break; case SIG_SETMASK: - current->blocked = *set; + newset = *set; break; default: - error = -EINVAL; + return -EINVAL; } + + spin_lock_irq(&tsk->sighand->siglock); + tsk->blocked = newset; recalc_sigpending(); - spin_unlock_irq(¤t->sighand->siglock); + spin_unlock_irq(&tsk->sighand->siglock); - return error; + return 0; } /** |