From: Arjan van de Ven <arjanv@redhat.com>
To: akpm@osdl.org, linux-scsi@vger.kernel.org
Subject: fix corruption in qla1280
Date: Mon, 14 Jul 2003 09:24:37 +0000 [thread overview]
Message-ID: <20030714092437.A4100@devserv.devel.redhat.com> (raw)
Hi,
In C, doing >> 32 on a 32 bit wide variable is undefined behavior, and the
code that gets generated by gcc (using the cpu shr) effectively means that
it's a nop. The patch below to qla1280.c fixes such a case, doing
>>16 twice looks more expensive but gcc optimizes it out while keeping
correct behavior.
Greetings,
Arjan van de Ven
--- linux-2.6.0-test1/drivers/scsi/qla1280.c~ 2003-07-14 11:21:51.233657418 +0200
+++ linux-2.6.0-test1/drivers/scsi/qla1280.c 2003-07-14 11:21:51.234657286 +0200
@@ -327,7 +327,7 @@
/* 3.16 */
#ifdef QLA_64BIT_PTR
#define pci_dma_lo32(a) (a & 0xffffffff)
-#define pci_dma_hi32(a) (a >> 32)
+#define pci_dma_hi32(a) ((a >> 16)>>16)
#else
#define pci_dma_lo32(a) (a & 0xffffffff)
#define pci_dma_hi32(a) 0
next reply other threads:[~2003-07-14 9:09 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-07-14 9:24 Arjan van de Ven [this message]
2003-07-14 20:43 ` fix corruption in qla1280 Kurt Garloff
2003-07-14 21:01 ` Arjan van de Ven
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