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Commit 706d5860 authored by Nicholas Bellinger's avatar Nicholas Bellinger
Browse files

target: Add WRITE_SAME (10) parsing and refactor passthrough checks 



This patch adds initial WRITE_SAME (10) w/ UNMAP=1 support following updates in
sbcr26 to allow UNMAP=1 for the non 16 + 32 byte CDB case.  It also refactors
current pSCSI passthrough passthrough checks into target_check_write_same_discard()
ahead of UNMAP=0 w/ write payload support into target_core_iblock.c.

This includes the support for handling WRITE_SAME in transport_emulate_control_cdb(),
and converts target_emulate_write_same to accept num_blocks directly for
WRITE_SAME, WRITE_SAME_16 and WRITE_SAME_32.

Reported-by: default avatarEric Seppanen <eric@purestorage.com>
Cc: Roland Dreier <roland@purestorage.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: default avatarNicholas Bellinger <nab@risingtidesystems.com>
parent 16ab8e60

drivers/target/target_core_cdb.c

+16 −12
Original line number Diff line number Diff line
@@ -1090,24 +1090,17 @@ err: 
 * Note this is not used for TCM/pSCSI passthrough

 */

static int

target_emulate_write_same(struct se_task *task, int write_same32)

target_emulate_write_same(struct se_task *task, u32 num_blocks)

{

	struct se_cmd *cmd = task->task_se_cmd;

	struct se_device *dev = cmd->se_dev;

	sector_t range;

	sector_t lba = cmd->t_task_lba;

	unsigned int num_blocks;

	int ret;

	/*

	 * Extract num_blocks from the WRITE_SAME_* CDB.  Then use the explict

	 * range when non zero is supplied, otherwise calculate the remaining

	 * range based on ->get_blocks() - starting LBA.

	 * Use the explicit range when non zero is supplied, otherwise calculate

	 * the remaining range based on ->get_blocks() - starting LBA.

	 */

	if (write_same32)

		num_blocks = get_unaligned_be32(&cmd->t_task_cdb[28]);

	else

		num_blocks = get_unaligned_be32(&cmd->t_task_cdb[10]);



	if (num_blocks != 0)

		range = num_blocks;

	else
@@ -1170,13 +1163,23 @@ transport_emulate_control_cdb(struct se_task *task) 
		}

		ret = target_emulate_unmap(task);

		break;

	case WRITE_SAME:

		if (!dev->transport->do_discard) {

			pr_err("WRITE_SAME emulation not supported"

					" for: %s\n", dev->transport->name);

			return PYX_TRANSPORT_UNKNOWN_SAM_OPCODE;

		}

		ret = target_emulate_write_same(task,

				get_unaligned_be16(&cmd->t_task_cdb[7]));

		break;

	case WRITE_SAME_16:

		if (!dev->transport->do_discard) {

			pr_err("WRITE_SAME_16 emulation not supported"

					" for: %s\n", dev->transport->name);

			return PYX_TRANSPORT_UNKNOWN_SAM_OPCODE;

		}

		ret = target_emulate_write_same(task, 0);

		ret = target_emulate_write_same(task,

				get_unaligned_be32(&cmd->t_task_cdb[10]));

		break;

	case VARIABLE_LENGTH_CMD:

		service_action =
@@ -1189,7 +1192,8 @@ transport_emulate_control_cdb(struct se_task *task) 
					dev->transport->name);

				return PYX_TRANSPORT_UNKNOWN_SAM_OPCODE;

			}

			ret = target_emulate_write_same(task, 1);

			ret = target_emulate_write_same(task,

				get_unaligned_be32(&cmd->t_task_cdb[28]));

			break;

		default:

			pr_err("Unsupported VARIABLE_LENGTH_CMD SA:"

drivers/target/target_core_transport.c

+57 −45
Original line number Diff line number Diff line
@@ -2861,6 +2861,38 @@ static int transport_cmd_get_valid_sectors(struct se_cmd *cmd) 
	return sectors;

}



static int target_check_write_same_discard(unsigned char *flags, struct se_device *dev)

{

	/*

	 * Determine if the received WRITE_SAME is used to for direct

	 * passthrough into Linux/SCSI with struct request via TCM/pSCSI

	 * or we are signaling the use of internal WRITE_SAME + UNMAP=1

	 * emulation for -> Linux/BLOCK disbard with TCM/IBLOCK code.

	 */

	int passthrough = (dev->transport->transport_type ==

				TRANSPORT_PLUGIN_PHBA_PDEV);



	if (!passthrough) {

		if ((flags[0] & 0x04) || (flags[0] & 0x02)) {

			pr_err("WRITE_SAME PBDATA and LBDATA"

				" bits not supported for Block Discard"

				" Emulation\n");

			return -ENOSYS;

		}

		/*

		 * Currently for the emulated case we only accept

		 * tpws with the UNMAP=1 bit set.

		 */

		if (!(flags[0] & 0x08)) {

			pr_err("WRITE_SAME w/o UNMAP bit not"

				" supported for Block Discard Emulation\n");

			return -ENOSYS;

		}

	}



	return 0;

}



/*	transport_generic_cmd_sequencer():

 *

 *	Generic Command Sequencer that should work for most DAS transport
@@ -3081,27 +3113,9 @@ static int transport_generic_cmd_sequencer( 
			cmd->t_task_lba = get_unaligned_be64(&cdb[12]);

			cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;



			/*

			 * Skip the remaining assignments for TCM/PSCSI passthrough

			 */

			if (passthrough)

				break;



			if ((cdb[10] & 0x04) || (cdb[10] & 0x02)) {

				pr_err("WRITE_SAME PBDATA and LBDATA"

					" bits not supported for Block Discard"

					" Emulation\n");

				goto out_invalid_cdb_field;

			}

			/*

			 * Currently for the emulated case we only accept

			 * tpws with the UNMAP=1 bit set.

			 */

			if (!(cdb[10] & 0x08)) {

				pr_err("WRITE_SAME w/o UNMAP bit not"

					" supported for Block Discard Emulation\n");

			if (target_check_write_same_discard(&cdb[10], dev) < 0)

				goto out_invalid_cdb_field;

			}



			break;

		default:

			pr_err("VARIABLE_LENGTH_CMD service action"
@@ -3358,33 +3372,31 @@ static int transport_generic_cmd_sequencer( 
		}



		cmd->t_task_lba = get_unaligned_be64(&cdb[2]);

		passthrough = (dev->transport->transport_type ==

				TRANSPORT_PLUGIN_PHBA_PDEV);

		/*

		 * Determine if the received WRITE_SAME_16 is used to for direct

		 * passthrough into Linux/SCSI with struct request via TCM/pSCSI

		 * or we are signaling the use of internal WRITE_SAME + UNMAP=1

		 * emulation for -> Linux/BLOCK disbard with TCM/IBLOCK and

		 * TCM/FILEIO subsystem plugin backstores.

		 */

		if (!passthrough) {

			if ((cdb[1] & 0x04) || (cdb[1] & 0x02)) {

				pr_err("WRITE_SAME PBDATA and LBDATA"

					" bits not supported for Block Discard"

					" Emulation\n");

		cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;



		if (target_check_write_same_discard(&cdb[1], dev) < 0)

			goto out_invalid_cdb_field;

		break;

	case WRITE_SAME:

		sectors = transport_get_sectors_10(cdb, cmd, &sector_ret);

		if (sector_ret)

			goto out_unsupported_cdb;



		if (sectors)

			size = transport_get_size(sectors, cdb, cmd);

		else {

			pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not supported\n");

			goto out_invalid_cdb_field;

		}



		cmd->t_task_lba = get_unaligned_be32(&cdb[2]);

		cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;

		/*

			 * Currently for the emulated case we only accept

			 * tpws with the UNMAP=1 bit set.

		 * Follow sbcr26 with WRITE_SAME (10) and check for the existence

		 * of byte 1 bit 3 UNMAP instead of original reserved field

		 */

			if (!(cdb[1] & 0x08)) {

				pr_err("WRITE_SAME w/o UNMAP bit not "

					" supported for Block Discard Emulation\n");

		if (target_check_write_same_discard(&cdb[1], dev) < 0)

			goto out_invalid_cdb_field;

			}

		}

		cmd->se_cmd_flags |= SCF_SCSI_CONTROL_SG_IO_CDB;

		break;

	case ALLOW_MEDIUM_REMOVAL:

	case GPCMD_CLOSE_TRACK: