scsi: scsi_debug: Implement VERIFY(10), add VERIFY(16)

With the addition of the per_host_store option, the ability to check
whether two different ramdisk images are the same or not becomes
practical. Prior to this patch VERIFY(10) always returned true (i.e.  the
SCSI GOOD status) without checking. This option adds support for BYTCHK
equal to 0, 1 and 3. If the comparison fails, then a sense key of
MISCOMPARE is returned as per the T10 standards. Also add support for the
VERIFY(16) command.

Link: https://lore.kernel.org/r/20200421151424.32668-4-dgilbert@interlog.comReviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/scsi_debug.c

@@ -354,7 +354,7 @@ enum sdeb_opcode_index {
 	SDEB_I_SERV_ACT_OUT_16 = 13,	/* add ...SERV_ACT_OUT_12 if needed */
 	SDEB_I_MAINT_IN = 14,
 	SDEB_I_MAINT_OUT = 15,
-	SDEB_I_VERIFY = 16,		/* 10 only */
+	SDEB_I_VERIFY = 16,		/* VERIFY(10), VERIFY(16) */
 	SDEB_I_VARIABLE_LEN = 17,	/* READ(32), WRITE(32), WR_SCAT(32) */
 	SDEB_I_RESERVE = 18,		/* 6, 10 */
 	SDEB_I_RELEASE = 19,		/* 6, 10 */
@@ -397,7 +397,8 @@ static const unsigned char opcode_ind_arr[256] = {
 	0, SDEB_I_VARIABLE_LEN,
 /* 0x80; 0x80->0x9f: 16 byte cdbs */
 	0, 0, 0, 0, 0, SDEB_I_ATA_PT, 0, 0,
-	SDEB_I_READ, SDEB_I_COMP_WRITE, SDEB_I_WRITE, 0, 0, 0, 0, 0,
+	SDEB_I_READ, SDEB_I_COMP_WRITE, SDEB_I_WRITE, 0,
+	0, 0, 0, SDEB_I_VERIFY,
 	0, SDEB_I_SYNC_CACHE, 0, SDEB_I_WRITE_SAME, 0, 0, 0, 0,
 	0, 0, 0, 0, 0, 0, SDEB_I_SERV_ACT_IN_16, SDEB_I_SERV_ACT_OUT_16,
 /* 0xa0; 0xa0->0xbf: 12 byte cdbs */
@@ -439,6 +440,7 @@ static int resp_report_tgtpgs(struct scsi_cmnd *, struct sdebug_dev_info *);
 static int resp_unmap(struct scsi_cmnd *, struct sdebug_dev_info *);
 static int resp_rsup_opcodes(struct scsi_cmnd *, struct sdebug_dev_info *);
 static int resp_rsup_tmfs(struct scsi_cmnd *, struct sdebug_dev_info *);
+static int resp_verify(struct scsi_cmnd *, struct sdebug_dev_info *);
 static int resp_write_same_10(struct scsi_cmnd *, struct sdebug_dev_info *);
 static int resp_write_same_16(struct scsi_cmnd *, struct sdebug_dev_info *);
 static int resp_comp_write(struct scsi_cmnd *, struct sdebug_dev_info *);
@@ -490,6 +492,12 @@ static const struct opcode_info_t write_iarr[] = {
 		   0xbf, 0xc7, 0, 0, 0, 0} },
 };
 
+static const struct opcode_info_t verify_iarr[] = {
+	{0, 0x2f, 0, F_D_OUT_MAYBE | FF_MEDIA_IO, resp_verify,/* VERIFY(10) */
+	    NULL, {10,  0xf7, 0xff, 0xff, 0xff, 0xff, 0xbf, 0xff, 0xff, 0xc7,
+		   0, 0, 0, 0, 0, 0} },
+};
+
 static const struct opcode_info_t sa_in_16_iarr[] = {
 	{0, 0x9e, 0x12, F_SA_LOW | F_D_IN, resp_get_lba_status, NULL,
 	    {16,  0x12, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
@@ -590,9 +598,10 @@ static const struct opcode_info_t opcode_info_arr[SDEB_I_LAST_ELEMENT + 1] = {
 /* 15 */
 	{0, 0, 0, F_INV_OP | FF_RESPOND, NULL, NULL, /* MAINT OUT */
 	    {0,  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0} },
-	{0, 0x2f, 0, F_D_OUT_MAYBE | FF_MEDIA_IO, NULL, NULL, /* VERIFY(10) */
-	    {10,  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xc7,
-	     0, 0, 0, 0, 0, 0} },
+	{ARRAY_SIZE(verify_iarr), 0x8f, 0,
+	    F_D_OUT_MAYBE | FF_MEDIA_IO, resp_verify,	/* VERIFY(16) */
+	    verify_iarr, {16,  0xf6, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+			  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x3f, 0xc7} },
 	{ARRAY_SIZE(vl_iarr), 0x7f, 0x9, F_SA_HIGH | F_D_IN | FF_MEDIA_IO,
 	    resp_read_dt0, vl_iarr,	/* VARIABLE LENGTH, READ(32) */
 	    {32,  0xc7, 0, 0, 0, 0, 0x3f, 0x18, 0x0, 0x9, 0xfe, 0, 0xff, 0xff,
@@ -2579,7 +2588,7 @@ static int do_dout_fetch(struct scsi_cmnd *scp, u32 num, u8 *doutp)
  * arr into sip->storep+lba and return true. If comparison fails then
  * return false. */
 static bool comp_write_worker(struct sdeb_store_info *sip, u64 lba, u32 num,
-			      const u8 *arr)
+			      const u8 *arr, bool compare_only)
 {
 	bool res;
 	u64 block, rest = 0;
@@ -2599,6 +2608,8 @@ static bool comp_write_worker(struct sdeb_store_info *sip, u64 lba, u32 num,
 			     rest * lb_size);
 	if (!res)
 		return res;
+	if (compare_only)
+		return true;
 	arr += num * lb_size;
 	memcpy(fsp + (block * lb_size), arr, (num - rest) * lb_size);
 	if (rest)
@@ -3524,7 +3535,7 @@ static int resp_comp_write(struct scsi_cmnd *scp,
 		sdev_printk(KERN_INFO, scp->device, "%s: compare_write: cdb "
 			    "indicated=%u, IO sent=%d bytes\n", my_name,
 			    dnum * lb_size, ret);
-	if (!comp_write_worker(sip, lba, num, arr)) {
+	if (!comp_write_worker(sip, lba, num, arr, false)) {
 		mk_sense_buffer(scp, MISCOMPARE, MISCOMPARE_VERIFY_ASC, 0);
 		retval = check_condition_result;
 		goto cleanup;
@@ -3771,6 +3782,82 @@ static int resp_report_luns(struct scsi_cmnd *scp,
 	return res;
 }
 
+static int resp_verify(struct scsi_cmnd *scp, struct sdebug_dev_info *devip)
+{
+	bool is_bytchk3 = false;
+	u8 bytchk;
+	int ret, j;
+	u32 vnum, a_num, off;
+	const u32 lb_size = sdebug_sector_size;
+	unsigned long iflags;
+	u64 lba;
+	u8 *arr;
+	u8 *cmd = scp->cmnd;
+	struct sdeb_store_info *sip = devip2sip(devip);
+	rwlock_t *macc_lckp = sip ? &sip->macc_lck : &sdeb_fake_rw_lck;
+
+	bytchk = (cmd[1] >> 1) & 0x3;
+	if (bytchk == 0) {
+		return 0;	/* always claim internal verify okay */
+	} else if (bytchk == 2) {
+		mk_sense_invalid_fld(scp, SDEB_IN_CDB, 2, 2);
+		return check_condition_result;
+	} else if (bytchk == 3) {
+		is_bytchk3 = true;	/* 1 block sent, compared repeatedly */
+	}
+	switch (cmd[0]) {
+	case VERIFY_16:
+		lba = get_unaligned_be64(cmd + 2);
+		vnum = get_unaligned_be32(cmd + 10);
+		break;
+	case VERIFY:		/* is VERIFY(10) */
+		lba = get_unaligned_be32(cmd + 2);
+		vnum = get_unaligned_be16(cmd + 7);
+		break;
+	default:
+		mk_sense_invalid_opcode(scp);
+		return check_condition_result;
+	}
+	a_num = is_bytchk3 ? 1 : vnum;
+	/* Treat following check like one for read (i.e. no write) access */
+	ret = check_device_access_params(scp, lba, a_num, false);
+	if (ret)
+		return ret;
+
+	arr = kcalloc(lb_size, vnum, GFP_ATOMIC);
+	if (!arr) {
+		mk_sense_buffer(scp, ILLEGAL_REQUEST, INSUFF_RES_ASC,
+				INSUFF_RES_ASCQ);
+		return check_condition_result;
+	}
+	/* Not changing store, so only need read access */
+	read_lock_irqsave(macc_lckp, iflags);
+
+	ret = do_dout_fetch(scp, a_num, arr);
+	if (ret == -1) {
+		ret = DID_ERROR << 16;
+		goto cleanup;
+	} else if (sdebug_verbose && (ret < (a_num * lb_size))) {
+		sdev_printk(KERN_INFO, scp->device,
+			    "%s: %s: cdb indicated=%u, IO sent=%d bytes\n",
+			    my_name, __func__, a_num * lb_size, ret);
+	}
+	if (is_bytchk3) {
+		for (j = 1, off = lb_size; j < vnum; ++j, off += lb_size)
+			memcpy(arr + off, arr, lb_size);
+	}
+	ret = 0;
+	if (!comp_write_worker(sip, lba, vnum, arr, true)) {
+		mk_sense_buffer(scp, MISCOMPARE, MISCOMPARE_VERIFY_ASC, 0);
+		ret = check_condition_result;
+		goto cleanup;
+	}
+cleanup:
+	read_unlock_irqrestore(macc_lckp, iflags);
+	kfree(arr);
+	return ret;
+}
+
 static struct sdebug_queue *get_queue(struct scsi_cmnd *cmnd)
 {
 	u32 tag = blk_mq_unique_tag(cmnd->request);