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| author | Arjan van de Ven <arjan@linux.intel.com> | 2009-01-11 15:35:01 +0000 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-01-12 16:39:58 -0800 |
| commit | 37a76bd4f1b716949fc38a6842e89f0ccb8384d0 (patch) | |
| tree | 6537cab6fb0e1a9508d34ca95b25808866bf04af /kernel/async.c | |
| parent | d32ad102c6d748b510fd89f1af4232eac1be8732 (diff) | |
| download | lwn-37a76bd4f1b716949fc38a6842e89f0ccb8384d0.tar.gz lwn-37a76bd4f1b716949fc38a6842e89f0ccb8384d0.zip | |
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>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/async.c')
| -rw-r--r-- | kernel/async.c | 21 |
1 files changed, 16 insertions, 5 deletions
diff --git a/kernel/async.c b/kernel/async.c index f286e9f2b736..608b32b42812 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(); |