[PATCH 3/8] scsi: sd_zbc: Verify that the zone size is a power of two

[Bart Van Assche <bvanassche@acm.org>]

The following check in sd_zbc_cmnd_checks() can only work correctly if
the zone size is a power of two:

	if (sector & (sd_zbc_zone_sectors(sdkp) - 1))
		/* Unaligned request */
		return BLK_STS_IOERR;

Hence this patch that verifies that the zone size is a power of two.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 drivers/scsi/sd_zbc.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/scsi/sd_zbc.c b/drivers/scsi/sd_zbc.c
index d0275855b16c..c1f295859b27 100644
--- a/drivers/scsi/sd_zbc.c
+++ b/drivers/scsi/sd_zbc.c
@@ -666,6 +666,13 @@ static int sd_zbc_check_capacity(struct scsi_disk *sdkp, unsigned char *buf,
 
 	*zblocks = zone_blocks;
 
+	if (!is_power_of_2(*zblocks)) {
+		sd_printk(KERN_ERR, sdkp,
+			  "Zone size %llu is not a power of two.\n",
+			  zone_blocks);
+		return -EINVAL;
+	}
+
 	return 0;
 }