linux-kernel - [PATCH 3/3] Move more common code from wait_task_*() to copy_wait_opts_to

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Date:	Wed, 13 May 2009 14:08:13 +0200
From:	Vitaly Mayatskikh <v.mayatskih@...il.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Oleg Nesterov <oleg@...hat.com>, Ingo Molnar <mingo@...e.hu>,
	Roland McGrath <roland@...hat.com>,
	linux-kernel@...r.kernel.org
Subject: [PATCH 3/3] Move more common code from wait_task_*() to copy_wait_opts_to_user()

Roland McGrath pointed to more common checks and put_user() around
invoke of copy_wait_opts_to_user() in wait_task_*() functions.
This common code is moved to copy_wait_opts_to_user().

Signed-off-by: Vitaly Mayatskikh <v.mayatskih@...il.com>
---
 kernel/exit.c |   40 ++++++++++++++++------------------------
 1 files changed, 16 insertions(+), 24 deletions(-)

diff --git a/kernel/exit.c b/kernel/exit.c
index cea85c9..cf41c2b 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1095,6 +1095,7 @@ struct wait_info {
 	int			why;
 	int			status;
 	int			signal;
+	int			stat;
 };
 
 static struct pid *task_pid_type(struct task_struct *task, enum pid_type type)
@@ -1151,6 +1152,10 @@ static int copy_wait_opts_to_user(struct wait_opts *wo, struct wait_info *wi)
 		if (!retval)
 			retval = put_user(wi->status, &infop->si_status);
 	}
+	if (!retval && wo->wo_stat)
+		retval = put_user(wi->stat, wo->wo_stat);
+	if (!retval)
+		retval = wi->pid;
 	return retval;
 }
 
@@ -1166,7 +1171,7 @@ static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p)
 	int retval, traced;
 	struct wait_info wi = { .p = p, .pid = task_pid_vnr(p),
 				.uid = __task_cred(p)->uid,
-				.signal = SIGCHLD };
+				.signal = SIGCHLD, .stat = 0 };
 
 	if (!likely(wo->wo_flags & WEXITED))
 		return 0;
@@ -1185,8 +1190,6 @@ static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p)
 		}
 		retval = copy_wait_opts_to_user(wo, &wi);
 		put_task_struct(p);
-		if (!retval)
-			retval = wi.pid;
 		return retval;
 	}
 
@@ -1268,24 +1271,19 @@ static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p)
 	 */
 	read_unlock(&tasklist_lock);
 
-	wi.status = (p->signal->flags & SIGNAL_GROUP_EXIT)
+	wi.stat = (p->signal->flags & SIGNAL_GROUP_EXIT)
 		? p->signal->group_exit_code : p->exit_code;
-	if (wo->wo_stat)
-		retval = put_user(wi.status, wo->wo_stat);
 
-	if ((wi.status & 0x7f) == 0) {
+	if ((wi.stat & 0x7f) == 0) {
 		wi.why = CLD_EXITED;
-		wi.status >>= 8;
+		wi.status = wi.stat >> 8;
 	} else {
-		wi.why = (wi.status & 0x80) ? CLD_DUMPED : CLD_KILLED;
-		wi.status &= 0x7f;
+		wi.why = (wi.stat & 0x80) ? CLD_DUMPED : CLD_KILLED;
+		wi.status = wi.stat & 0x7f;
 	}
 
 	retval = copy_wait_opts_to_user(wo, &wi);
 
-	if (!retval)
-		retval = wi.pid;
-
 	if (traced) {
 		write_lock_irq(&tasklist_lock);
 		/* We dropped tasklist, ptracer could die and untrace */
@@ -1369,16 +1367,14 @@ unlock_sig:
 	 * possibly take page faults for user memory.
 	 */
 	get_task_struct(p);
+	read_unlock(&tasklist_lock);
+
 	wi.pid = task_pid_vnr(p);
 	wi.why = ptrace ? CLD_TRAPPED : CLD_STOPPED;
-	read_unlock(&tasklist_lock);
+	wi.stat = (wi.status << 8) | 0x7f;
 
 	retval = copy_wait_opts_to_user(wo, &wi);
 
-	if (!retval && wo->wo_stat)
-		retval = put_user((wi.status << 8) | 0x7f, wo->wo_stat);
-	if (!retval)
-		retval = wi.pid;
 	put_task_struct(p);
 
 	BUG_ON(!retval);
@@ -1395,7 +1391,8 @@ static int wait_task_continued(struct wait_opts *wo, struct task_struct *p)
 {
 	int retval;
 	struct wait_info wi = { .p = p, .why = CLD_CONTINUED,
-				.status = SIGCONT, .signal = SIGCHLD };
+				.status = SIGCONT, .signal = SIGCHLD,
+				.stat = 0xffff };
 
 	if (!unlikely(wo->wo_flags & WCONTINUED))
 		return 0;
@@ -1422,11 +1419,6 @@ static int wait_task_continued(struct wait_opts *wo, struct task_struct *p)
 
 	put_task_struct(p);
 
-	if (!retval && wo->wo_stat)
-		retval = put_user(0xffff, wo->wo_stat);
-	if (!retval)
-		retval = wi.pid;
-
 	BUG_ON(retval == 0);
 
 	return retval;
-- 
1.6.2.2

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