scsi: sd_zbc: Rename sd_zbc_check_zones()

Now that the block layer implement zone checks on revalidate,
sd_zbc_check_zones() is reduced getting the zone size and verifying the
device capacity for device with RC_BASIS=0. Be clear about this by renaming
sd_zbc_check_zones() to sd_zbc_check_capacity() and updating the function
description and comments.

Link: https://lore.kernel.org/r/20191220075823.400072-3-damien.lemoal@wdc.comSigned-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/sd_zbc.c

@@ -325,19 +325,21 @@ static int sd_zbc_check_zoned_characteristics(struct scsi_disk *sdkp,
 }
 
 /**
- * sd_zbc_check_zones - Check the device capacity and zone size
+ * sd_zbc_check_capacity - Check the device capacity
  * @sdkp: Target disk
+ * @buf: command buffer
+ * @zblock: zone size in number of blocks
  *
- * Check that the device capacity as reported by READ CAPACITY matches the
- * max_lba value (plus one)of the report zones command reply.
+ * Get the device zone size and check that the device capacity as reported
+ * by READ CAPACITY matches the max_lba value (plus one) of the report zones
+ * command reply for devices with RC_BASIS == 0.
  *
- * Returns the zone size in number of blocks upon success or an error code
- * upon failure.
+ * Returns 0 upon success or an error code upon failure.
  */
-static int sd_zbc_check_zones(struct scsi_disk *sdkp, unsigned char *buf,
-			      u32 *zblocks)
+static int sd_zbc_check_capacity(struct scsi_disk *sdkp, unsigned char *buf,
+				 u32 *zblocks)
 {
-	u64 zone_blocks = 0;
+	u64 zone_blocks;
 	sector_t max_lba;
 	unsigned char *rec;
 	int ret;
@@ -360,7 +362,7 @@ static int sd_zbc_check_zones(struct scsi_disk *sdkp, unsigned char *buf,
 		}
 	}
 
-	/* Parse REPORT ZONES header */
+	/* Get the size of the first reported zone */
 	rec = buf + 64;
 	zone_blocks = get_unaligned_be64(&rec[8]);
 	if (logical_to_sectors(sdkp->device, zone_blocks) > UINT_MAX) {
@@ -394,11 +396,8 @@ int sd_zbc_read_zones(struct scsi_disk *sdkp, unsigned char *buf)
 	if (ret)
 		goto err;
 
-	/*
-	 * Check zone size: only devices with a constant zone size (except
-	 * an eventual last runt zone) that is a power of 2 are supported.
-	 */
-	ret = sd_zbc_check_zones(sdkp, buf, &zone_blocks);
+	/* Check the device capacity reported by report zones */
+	ret = sd_zbc_check_capacity(sdkp, buf, &zone_blocks);
 	if (ret != 0)
 		goto err;