Use write_trylock_irqsave in ptrace_attach

This patch makes ptrace_attach use write_trylock_irqsave().

[akpm@linux-foundation.org: remove unneeded initialisation]
Signed-off-by: Sripathi Kodi <sripathik@in.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index ad7949a..b1d11f1 100644 (file)
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -161,6 +161,7 @@ int ptrace_may_attach(struct task_struct *task)
 int ptrace_attach(struct task_struct *task)
 {
        int retval;
+       unsigned long flags;
 
        audit_ptrace(task);
 
@@ -181,9 +182,7 @@ repeat:
         * cpu's that may have task_lock).
         */
        task_lock(task);
-       local_irq_disable();
-       if (!write_trylock(&tasklist_lock)) {
-               local_irq_enable();
+       if (!write_trylock_irqsave(&tasklist_lock, flags)) {
                task_unlock(task);
                do {
                        cpu_relax();
@@ -211,7 +210,7 @@ repeat:
        force_sig_specific(SIGSTOP, task);
 
 bad:
-       write_unlock_irq(&tasklist_lock);
+       write_unlock_irqrestore(&tasklist_lock, flags);
        task_unlock(task);
 out:
        return retval;