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From: Arnd Bergmann <arnd@arndb.de>
To: Martin Schwidefsky <schwidefsky@de.ibm.com>,
	Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	linux-kernel@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
	Sebastian Ott <sebott@linux.vnet.ibm.com>,
	Gerald Schaefer <gerald.schaefer@de.ibm.com>,
	Joerg Roedel <jroedel@suse.de>,
	Christian Borntraeger <borntraeger@de.ibm.com>,
	linux-s390@vger.kernel.org
Subject: [PATCH 25/28] s390: pci: don't print uninitialized data for debugging
Date: Tue, 18 Oct 2016 00:16:13 +0200	[thread overview]
Message-ID: <20161017221650.1902729-6-arnd@arndb.de> (raw)
In-Reply-To: <20161017220342.1627073-1-arnd@arndb.de>

gcc correctly warns about an incorrect use of the 'pa' variable
in case we pass an empty scatterlist to __s390_dma_map_sg:

arch/s390/pci/pci_dma.c: In function '__s390_dma_map_sg':
arch/s390/pci/pci_dma.c:309:13: warning: 'pa' may be used uninitialized in this function [-Wmaybe-uninitialized]

This adds a bogus initialization to the function to sanitize
the debug output.  I would have preferred a solution without
the initialization, but I only got the report from the
kbuild bot after turning on the warning again, and didn't
manage to reproduce it myself.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 arch/s390/pci/pci_dma.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/s390/pci/pci_dma.c b/arch/s390/pci/pci_dma.c
index 7350c8b..6b2f72f 100644
--- a/arch/s390/pci/pci_dma.c
+++ b/arch/s390/pci/pci_dma.c
@@ -423,7 +423,7 @@ static int __s390_dma_map_sg(struct device *dev, struct scatterlist *sg,
 	dma_addr_t dma_addr_base, dma_addr;
 	int flags = ZPCI_PTE_VALID;
 	struct scatterlist *s;
-	unsigned long pa;
+	unsigned long pa = 0;
 	int ret;
 
 	size = PAGE_ALIGN(size);
-- 
2.9.0

  reply	other threads:[~2016-10-17 22:16 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-10-17 22:03 [PATCH 00/28] Reenable maybe-uninitialized warnings Arnd Bergmann
2016-10-17 22:16 ` Arnd Bergmann [this message]
2016-10-18  6:48   ` [PATCH 25/28] s390: pci: don't print uninitialized data for debugging Martin Schwidefsky
2016-10-18  8:53     ` Sebastian Ott
2016-10-17 22:19 ` [PATCH 28/28] Kbuild: bring back -Wmaybe-uninitialized warning Arnd Bergmann
2016-10-18  5:08 ` [PATCH 00/28] Reenable maybe-uninitialized warnings Christoph Hellwig

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