From: Tim Bird <tim.bird@am.sony.com>
To: Greg KH <gregkh@linuxfoundation.org>,
linux-embedded <linux-embedded@vger.kernel.org>,
linux kernel <linux-kernel@vger.kernel.org>,
Brian Swetland <swetland@google.com>,
Dima Zavin <dima@android.com>, Andrew Morton <akpm@osdl.org>
Subject: [PATCH 3/5] logger: reorder prepare_to_wait and mutex_lock
Date: Tue, 7 Feb 2012 18:30:09 -0800 [thread overview]
Message-ID: <4F31DE31.3040001@am.sony.com> (raw)
In-Reply-To: <4F31DC31.6040303@am.sony.com>
If mutex_lock waits, it will return in state TASK_RUNNING,
rubbing out the effect of prepare_to_wait().
Signed-off-by: Tim Bird <tim.bird@am.sony.com>
---
drivers/staging/android/logger.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)
diff --git a/drivers/staging/android/logger.c b/drivers/staging/android/logger.c
index 92cfd94..54b7cdf 100644
--- a/drivers/staging/android/logger.c
+++ b/drivers/staging/android/logger.c
@@ -172,9 +172,10 @@ static ssize_t logger_read(struct file *file, char __user *buf,
start:
while (1) {
+ mutex_lock(&log->mutex);
+
prepare_to_wait(&log->wq, &wait, TASK_INTERRUPTIBLE);
- mutex_lock(&log->mutex);
ret = (log->w_off == reader->r_off);
mutex_unlock(&log->mutex);
if (!ret)
--
1.7.2.3
next prev parent reply other threads:[~2012-02-08 2:30 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-08 2:21 [PATCH 1/5] logger: Change logger_offset() from macro to function Tim Bird
2012-02-08 2:28 ` [PATCH 2/5] logger: simplify and optimize get_entry_len Tim Bird
2012-02-08 18:37 ` [PATCH 2/5 v2] " Tim Bird
2012-02-09 5:15 ` Dima Zavin
2012-02-09 5:58 ` Tim Bird
2012-02-08 2:30 ` Tim Bird [this message]
2012-02-09 5:56 ` [PATCH 3/5] logger: reorder prepare_to_wait and mutex_lock Dima Zavin
2012-02-08 2:32 ` [PATCH 4/5] logger: clarify code in clock_interval Tim Bird
2012-02-09 6:09 ` Dima Zavin
2012-02-08 2:34 ` [PATCH 5/5] logger: clarify non-update of w_off in do_write_log_from_user Tim Bird
2012-02-09 6:10 ` Dima Zavin
2012-02-08 3:22 ` [PATCH 1/5] logger: Change logger_offset() from macro to function Frank Rowand
2012-02-09 4:54 ` Dima Zavin
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