sd: fix uninitialized variable access in error handling

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 <arnd@arndb.de>
Reviewed-by: Shaun Tancheff <shaun.tancheff@seagate.com>
Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/drivers/scsi/sd_zbc.c b/drivers/scsi/sd_zbc.c
index 16d3fa62d8acbf87c79d2fd1593e9c7e160793e9..d5b3bd915d9eb4c42c1f48def5c0864601c82f5d 100644 (file)
--- 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) {