linux-kernel - [PATCH 5/7] scsi: qla4xxx: shut up warning for rd_reg

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Message-Id: <1453910247-3447628-6-git-send-email-arnd@arndb.de>
Date:	Wed, 27 Jan 2016 16:57:21 +0100
From:	Arnd Bergmann <arnd@...db.de>
To:	"Martin K. Petersen" <martin.petersen@...cle.com>,
	James.Bottomley@...senPartnership.com
Cc:	linux-arm-kernel@...ts.infradead.org,
	Arnd Bergmann <arnd@...db.de>, linux-scsi@...r.kernel.org,
	"James E.J. Bottomley" <JBottomley@...n.com>,
	QLogic-Storage-Upstream@...gic.com, linux-kernel@...r.kernel.org
Subject: [PATCH 5/7] scsi: qla4xxx: shut up warning for rd_reg_indirect

The qla4_83xx_rd_reg_indirect() function can fail when it is unable
to read a register, but not all callers check its return value before
using the register data, and gcc correctly warns about this:

qla4xxx/ql4_83xx.c: In function 'qla4_83xx_process_reset_template':
qla4xxx/ql4_83xx.c:1073:36: warning: 'value' may be used uninitialized in this function
     ha->reset_tmplt.array[index++] = value;
                                    ^
qla4xxx/ql4_83xx.c:1050:11: note: 'value' was declared here
  uint32_t value;
           ^
qla4xxx/ql4_83xx.c:902:8: warning: 'value' may be used uninitialized in this function
  value &= p_rmw_hdr->test_mask;
        ^
qla4xxx/ql4_83xx.c:895:11: note: 'value' was declared here
  uint32_t value;
           ^
In file included from ../include/linux/io.h:25:0,
                 from ../include/linux/pci.h:31,
                 from ../drivers/scsi/qla4xxx/ql4_def.h:16,
                 from ../drivers/scsi/qla4xxx/ql4_83xx.c:10:
asm/io.h:101:2: warning: 'value' may be used uninitialized in this function
  asm volatile("str %1, %0"
  ^
qla4xxx/ql4_83xx.c:874:11: note: 'value' was declared here
  uint32_t value;
           ^

Unfortunately, I don't see any helpful way to add proper error handling
for this case, and the failure scenario for rd_reg seems rather obscure,
so this bails out and makes the rd_reg accessor set the result to 0xffffffff
so we at least get a predictable value.

Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
 drivers/scsi/qla4xxx/ql4_83xx.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/qla4xxx/ql4_83xx.c b/drivers/scsi/qla4xxx/ql4_83xx.c
index 5d4f8e67fb25..638f72c5ab05 100644
--- a/drivers/scsi/qla4xxx/ql4_83xx.c
+++ b/drivers/scsi/qla4xxx/ql4_83xx.c
@@ -46,11 +46,13 @@ int qla4_83xx_rd_reg_indirect(struct scsi_qla_host *ha, uint32_t addr,
 
 	ret_val = qla4_83xx_set_win_base(ha, addr);
 
-	if (ret_val == QLA_SUCCESS)
+	if (ret_val == QLA_SUCCESS) {
 		*data = qla4_83xx_rd_reg(ha, QLA83XX_WILDCARD);
-	else
+	} else {
+		*data = 0xffffffff;
 		ql4_printk(KERN_ERR, ha, "%s: failed read of addr 0x%x!\n",
 			   __func__, addr);
+	}
 
 	return ret_val;
 }
-- 
2.7.0