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[PATCH 5/7] scsi: qla4xxx: shut up warning for rd_reg_indirect

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  [PATCH 5/7] scsi: qla4xxx: shut up warning for rd_reg_indirect Arnd Bergmann <arnd@arndb.de> - 2016-01-27 17:00 +0100

#1319100 — [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@arndb.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

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