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From: Dan Carpenter <dan.carpenter@oracle.com>
To: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	David Fries <David@Fries.net>,
	Matt Campbell <mattrcampbell@gmail.com>,
	linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: [patch] [patch 2/2 v2] w1: use correct lock on error in w1_seq_show()
Date: Thu, 4 Jun 2015 12:04:12 +0300	[thread overview]
Message-ID: <20150604090412.GE22838@mwanda> (raw)
In-Reply-To: <20150602121255.GA20149@spacedout.fries.net>

I noticed there was a problem here because Smatch complained:

	drivers/w1/slaves/w1_therm.c:416 w1_seq_show() warn:
	inconsistent returns 'mutex:&sl->master->mutex'.
	  Locked on:   line 416
	  Unlocked on: line 413

The problem is that we lock ->mutex but we unlock ->bus_mutex on error.
David Fries says that ->bus_mutex is correct and ->mutex is incorrect.

Fixes: d9411e57dc7f ('w1: Add support for DS28EA00 sequence to w1-therm')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
v2: In the first version I changed ->bus_mutext to ->mutex instead of
    the other way around.

diff --git a/drivers/w1/slaves/w1_therm.c b/drivers/w1/slaves/w1_therm.c
index d21e686..06b034c 100644
--- a/drivers/w1/slaves/w1_therm.c
+++ b/drivers/w1/slaves/w1_therm.c
@@ -355,7 +355,7 @@ static ssize_t w1_seq_show(struct device *device,
 	struct w1_reg_num *reg_num;
 	int seq = 0;
 
-	mutex_lock(&sl->master->mutex);
+	mutex_lock(&sl->master->bus_mutex);
 	/* Place all devices in CHAIN state */
 	if (w1_reset_bus(sl->master))
 		goto error;
@@ -407,7 +407,7 @@ static ssize_t w1_seq_show(struct device *device,
 	ack = w1_read_8(sl->master);
 	if (ack != W1_42_SUCCESS_CONFIRM_BYTE)
 		goto error;
-	mutex_unlock(&sl->master->mutex);
+	mutex_unlock(&sl->master->bus_mutex);
 
 	c -= snprintf(buf + PAGE_SIZE - c, c, "%d\n", seq);
 	return PAGE_SIZE - c;

  parent reply	other threads:[~2015-06-04  9:05 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-06-01  9:56 [patch 2/2] w1: unlock correct lock on error in w1_seq_show() Dan Carpenter
2015-06-02 12:12 ` David Fries
     [not found]   ` <CA+gYwTGSBAjSPyUSUwknOmm8SoFzHFdJmoYPVA9yN61aWO7sdA@mail.gmail.com>
2015-06-03  1:07     ` David Fries
2015-06-03  1:54       ` Matt Campbell
2015-06-03  2:39         ` David Fries
2015-06-04  9:04   ` Dan Carpenter [this message]
2015-06-11 15:31     ` [patch] [patch 2/2 v2] w1: use " Evgeniy Polyakov
2015-06-11 23:41       ` David Fries

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