scsi: device_handler: remove VLAs

In preparation to enabling -Wvla, remove VLAs and replace them with
fixed-length arrays instead.

scsi_dh_{alua,emc,rdac} use variable-length array declarations to store
command blocks, with the appropriate size as determined by
COMMAND_SIZE. This patch replaces these with fixed-sized arrays using
MAX_COMMAND_SIZE, so that the array size can be determined at compile
time.

This was prompted by https://lkml.org/lkml/2018/3/7/621Signed-off-by: Stephen Kitt <steve@sk2.org>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/device_handler/scsi_dh_alua.c

@@ -138,12 +138,12 @@ static void release_port_group(struct kref *kref)
 static int submit_rtpg(struct scsi_device *sdev, unsigned char *buff,
 		       int bufflen, struct scsi_sense_hdr *sshdr, int flags)
 {
-	u8 cdb[COMMAND_SIZE(MAINTENANCE_IN)];
+	u8 cdb[MAX_COMMAND_SIZE];
 	int req_flags = REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
 		REQ_FAILFAST_DRIVER;
 
 	/* Prepare the command. */
-	memset(cdb, 0x0, COMMAND_SIZE(MAINTENANCE_IN));
+	memset(cdb, 0x0, MAX_COMMAND_SIZE);
 	cdb[0] = MAINTENANCE_IN;
 	if (!(flags & ALUA_RTPG_EXT_HDR_UNSUPP))
 		cdb[1] = MI_REPORT_TARGET_PGS | MI_EXT_HDR_PARAM_FMT;
@@ -166,7 +166,7 @@ static int submit_rtpg(struct scsi_device *sdev, unsigned char *buff,
 static int submit_stpg(struct scsi_device *sdev, int group_id,
 		       struct scsi_sense_hdr *sshdr)
 {
-	u8 cdb[COMMAND_SIZE(MAINTENANCE_OUT)];
+	u8 cdb[MAX_COMMAND_SIZE];
 	unsigned char stpg_data[8];
 	int stpg_len = 8;
 	int req_flags = REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
@@ -178,7 +178,7 @@ static int submit_stpg(struct scsi_device *sdev, int group_id,
 	put_unaligned_be16(group_id, &stpg_data[6]);
 
 	/* Prepare the command. */
-	memset(cdb, 0x0, COMMAND_SIZE(MAINTENANCE_OUT));
+	memset(cdb, 0x0, MAX_COMMAND_SIZE);
 	cdb[0] = MAINTENANCE_OUT;
 	cdb[1] = MO_SET_TARGET_PGS;
 	put_unaligned_be32(stpg_len, &cdb[6]);

drivers/scsi/device_handler/scsi_dh_emc.c

@@ -249,7 +249,7 @@ static int send_trespass_cmd(struct scsi_device *sdev,
 			    struct clariion_dh_data *csdev)
 {
 	unsigned char *page22;
-	unsigned char cdb[COMMAND_SIZE(MODE_SELECT)];
+	unsigned char cdb[MAX_COMMAND_SIZE];
 	int err, res = SCSI_DH_OK, len;
 	struct scsi_sense_hdr sshdr;
 	u64 req_flags = REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |

drivers/scsi/device_handler/scsi_dh_rdac.c

@@ -533,7 +533,7 @@ static void send_mode_select(struct work_struct *work)
 	int err = SCSI_DH_OK, retry_cnt = RDAC_RETRY_COUNT;
 	struct rdac_queue_data *tmp, *qdata;
 	LIST_HEAD(list);
-	unsigned char cdb[COMMAND_SIZE(MODE_SELECT_10)];
+	unsigned char cdb[MAX_COMMAND_SIZE];
 	struct scsi_sense_hdr sshdr;
 	unsigned int data_size;
 	u64 req_flags = REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |