linux-kernel - [PATCH 14/19] ptrace: restructure ptrace

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Date:	Tue, 24 May 2011 20:37:34 +0200
From:	Tejun Heo <tj@...nel.org>
To:	oleg@...hat.com
Cc:	vda.linux@...glemail.com, jan.kratochvil@...hat.com,
	linux-kernel@...r.kernel.org, torvalds@...ux-foundation.org,
	akpm@...ux-foundation.org, indan@....nu, bdonlan@...il.com,
	pedro@...esourcery.com, Tejun Heo <tj@...nel.org>
Subject: [PATCH 14/19] ptrace: restructure ptrace_getsiginfo()

Flatten ptrace_getsiginfo() to prepare for more logic in the success
path.  While at it, remove [un]likely() on child->last_siginfo check -
signal delivery and group stop traps can only be distinguished by NULL
siginfo and group stop isn't that unlikely.

This patch doesn't introduce any functional change.

Signed-off-by: Tejun Heo <tj@...nel.org>
---
 kernel/ptrace.c |   21 ++++++++++++---------
 1 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/kernel/ptrace.c b/kernel/ptrace.c
index 3911567..851870c 100644
--- a/kernel/ptrace.c
+++ b/kernel/ptrace.c
@@ -572,16 +572,19 @@ static int ptrace_setoptions(struct task_struct *child, unsigned long data)
 static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info)
 {
 	unsigned long flags;
-	int error = -ESRCH;
+	int error;
 
-	if (lock_task_sighand(child, &flags)) {
-		error = -EINVAL;
-		if (likely(child->last_siginfo != NULL)) {
-			*info = *child->last_siginfo;
-			error = 0;
-		}
-		unlock_task_sighand(child, &flags);
-	}
+	if (!lock_task_sighand(child, &flags))
+		return -ESRCH;
+
+	error = -EINVAL;
+	if (!child->last_siginfo)
+		goto out_unlock;
+
+	error = 0;
+	*info = *child->last_siginfo;
+out_unlock:
+	unlock_task_sighand(child, &flags);
 	return error;
 }
 
-- 
1.7.1

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