[PATCH] sd: fix uninitialized variable access in error handling

[Arnd Bergmann]

If sd_zbc_report_zones fails, the check for 'zone_blocks == 0'
later in the function accesses uninitialized data:

drivers/scsi/sd_zbc.c: In function ‘sd_zbc_read_zones’:
drivers/scsi/sd_zbc.c:520:7: error: ‘zone_blocks’ may be used uninitialized in 
this function [-Werror=maybe-uninitialized]

This sets it to zero, which has the desired effect of leaving
the sd_zbc_read_zones successfully with sdkp->zone_blocks = 0.

Fixes: 89d947561077 ("sd: Implement support for ZBC devices")
Signed-off-by: Arnd Bergmann <a...@arndb.de>
---
 drivers/scsi/sd_zbc.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/sd_zbc.c b/drivers/scsi/sd_zbc.c
index 16d3fa62d8ac..d5b3bd915d9e 100644
--- a/drivers/scsi/sd_zbc.c
+++ b/drivers/scsi/sd_zbc.c
@@ -455,8 +455,10 @@ static int sd_zbc_check_zone_size(struct scsi_disk *sdkp)
 
        /* Do a report zone to get the same field */
        ret = sd_zbc_report_zones(sdkp, buf, SD_ZBC_BUF_SIZE, 0);
-       if (ret)
+       if (ret) {
+               zone_blocks = 0;
                goto out;
+       }
 
        same = buf[4] & 0x0f;
        if (same > 0) {
-- 
2.9.0