lkml.org 
[lkml]   [2009]   [Jan]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH] async: fix __lowest_in_progress()
From 24bafdeb8a42e2e43a1928ca72159e6ff90cfe85 Mon Sep 17 00:00:00 2001
From: Arjan van de Ven <arjan@linux.intel.com>
Date: Sun, 11 Jan 2009 15:35:01 +0000
Subject: [PATCH] async: fix __lowest_in_progress()

At 37000 feet somewhere near Greenland I woke up from a half-sleep with the
realisation that __lowest_in_progress() is buggy. After landing I checked
and there were indeed 2 problems with it; this patch fixes both:
* The order of the list checks was wrong
* The locking was not correct.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
---
kernel/async.c | 21 ++++++++++++++++-----
1 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/kernel/async.c b/kernel/async.c
index f286e9f..608b32b 100644
--- a/kernel/async.c
+++ b/kernel/async.c
@@ -90,12 +90,12 @@ extern int initcall_debug;
static async_cookie_t __lowest_in_progress(struct list_head *running)
{
struct async_entry *entry;
- if (!list_empty(&async_pending)) {
- entry = list_first_entry(&async_pending,
+ if (!list_empty(running)) {
+ entry = list_first_entry(running,
struct async_entry, list);
return entry->cookie;
- } else if (!list_empty(running)) {
- entry = list_first_entry(running,
+ } else if (!list_empty(&async_pending)) {
+ entry = list_first_entry(&async_pending,
struct async_entry, list);
return entry->cookie;
} else {
@@ -104,6 +104,17 @@ static async_cookie_t __lowest_in_progress(struct list_head *running)
}

}
+
+static async_cookie_t lowest_in_progress(struct list_head *running)
+{
+ unsigned long flags;
+ async_cookie_t ret;
+
+ spin_lock_irqsave(&async_lock, flags);
+ ret = __lowest_in_progress(running);
+ spin_unlock_irqrestore(&async_lock, flags);
+ return ret;
+}
/*
* pick the first pending entry and run it
*/
@@ -229,7 +240,7 @@ void async_synchronize_cookie_special(async_cookie_t cookie, struct list_head *r
starttime = ktime_get();
}

- wait_event(async_done, __lowest_in_progress(running) >= cookie);
+ wait_event(async_done, lowest_in_progress(running) >= cookie);

if (initcall_debug && system_state == SYSTEM_BOOTING) {
endtime = ktime_get();
--
1.6.0.6


--
Arjan van de Ven Intel Open Source Technology Centre
For development, discussion and tips for power savings,
visit http://www.lesswatts.org


\
 
 \ /
  Last update: 2009-01-12 11:17    [W:0.023 / U:0.488 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site