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From: Jens Axboe <[email protected]>
To: [email protected], [email protected]
Cc: [email protected], [email protected], Jens Axboe <[email protected]>
Subject: [PATCH 2/5] exit: move core of do_wait() into helper
Date: Wed,  2 Aug 2023 17:14:39 -0600	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

Rather than have a maze of gotos, put the actual logic in __do_wait()
and have do_wait() loop deal with waitqueue setup/teardown and whether
to call __do_wait() again.

No functional changes intended in this patch.

Acked-by: Christian Brauner <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
---
 kernel/exit.c | 49 ++++++++++++++++++++++++++++++-------------------
 1 file changed, 30 insertions(+), 19 deletions(-)

diff --git a/kernel/exit.c b/kernel/exit.c
index 2809dad69492..d8fb124cc038 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1590,16 +1590,10 @@ static int do_wait_pid(struct wait_opts *wo)
 	return 0;
 }
 
-static long do_wait(struct wait_opts *wo)
+static long __do_wait(struct wait_opts *wo)
 {
-	int retval;
-
-	trace_sched_process_wait(wo->wo_pid);
+	long retval;
 
-	init_waitqueue_func_entry(&wo->child_wait, child_wait_callback);
-	wo->child_wait.private = current;
-	add_wait_queue(&current->signal->wait_chldexit, &wo->child_wait);
-repeat:
 	/*
 	 * If there is nothing that can match our criteria, just get out.
 	 * We will clear ->notask_error to zero if we see any child that
@@ -1617,18 +1611,18 @@ static long do_wait(struct wait_opts *wo)
 	if (wo->wo_type == PIDTYPE_PID) {
 		retval = do_wait_pid(wo);
 		if (retval)
-			goto end;
+			return retval;
 	} else {
 		struct task_struct *tsk = current;
 
 		do {
 			retval = do_wait_thread(wo, tsk);
 			if (retval)
-				goto end;
+				return retval;
 
 			retval = ptrace_do_wait(wo, tsk);
 			if (retval)
-				goto end;
+				return retval;
 
 			if (wo->wo_flags & __WNOTHREAD)
 				break;
@@ -1638,14 +1632,31 @@ static long do_wait(struct wait_opts *wo)
 
 notask:
 	retval = wo->notask_error;
-	if (!retval && !(wo->wo_flags & WNOHANG)) {
-		retval = -ERESTARTSYS;
-		if (!signal_pending(current)) {
-			schedule();
-			goto repeat;
-		}
-	}
-end:
+	if (!retval && !(wo->wo_flags & WNOHANG))
+		return -ERESTARTSYS;
+
+	return retval;
+}
+
+static long do_wait(struct wait_opts *wo)
+{
+	int retval;
+
+	trace_sched_process_wait(wo->wo_pid);
+
+	init_waitqueue_func_entry(&wo->child_wait, child_wait_callback);
+	wo->child_wait.private = current;
+	add_wait_queue(&current->signal->wait_chldexit, &wo->child_wait);
+
+	do {
+		retval = __do_wait(wo);
+		if (retval != -ERESTARTSYS)
+			break;
+		if (signal_pending(current))
+			break;
+		schedule();
+	} while (1);
+
 	__set_current_state(TASK_RUNNING);
 	remove_wait_queue(&current->signal->wait_chldexit, &wo->child_wait);
 	return retval;
-- 
2.40.1


  parent reply	other threads:[~2023-08-02 23:15 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-08-02 23:14 [PATCHSET v2] Add io_uring support for waitid Jens Axboe
2023-08-02 23:14 ` [PATCH 1/5] exit: abtract out should_wake helper for child_wait_callback() Jens Axboe
2023-08-02 23:14 ` Jens Axboe [this message]
2023-08-02 23:14 ` [PATCH 3/5] exit: add kernel_waitid_prepare() helper Jens Axboe
2023-08-02 23:14 ` [PATCH 4/5] exit: add internal include file with helpers Jens Axboe
2023-08-02 23:14 ` [PATCH 5/5] io_uring: add IORING_OP_WAITID support Jens Axboe
2023-08-09 11:27   ` Christian Brauner
2023-08-09 15:11     ` Jens Axboe
  -- strict thread matches above, loose matches on Subject: below --
2023-09-09 15:11 [PATCHSET v4 0/5] Add io_uring support for waitid Jens Axboe
2023-09-09 15:11 ` [PATCH 2/5] exit: move core of do_wait() into helper Jens Axboe
2023-08-11 14:16 [PATCHSET v3 0/5] Add io_uring support for waitid Jens Axboe
2023-08-11 14:16 ` [PATCH 2/5] exit: move core of do_wait() into helper Jens Axboe
2023-07-11 20:43 [PATCHSET 0/5] Add io_uring support for waitid Jens Axboe
2023-07-11 20:43 ` [PATCH 2/5] exit: move core of do_wait() into helper Jens Axboe
2023-07-14 15:32   ` Christian Brauner

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