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Commit 046ba642 authored by Nicholas Bellinger's avatar Nicholas Bellinger
Browse files

target: Drop arbitrary maximum I/O size limit 



This patch drops the arbitrary maximum I/O size limit in sbc_parse_cdb(),
which currently for fabric_max_sectors is hardcoded to 8192 (4 MB for 512
byte sector devices), and for hw_max_sectors is a backend driver dependent
value.

This limit is problematic because Linux initiators have only recently
started to honor block limits MAXIMUM TRANSFER LENGTH, and other non-Linux
based initiators (eg: MSFT Fibre Channel) can also generate I/Os larger
than 4 MB in size.

Currently when this happens, the following message will appear on the
target resulting in I/Os being returned with non recoverable status:

  SCSI OP 28h with too big sectors 16384 exceeds fabric_max_sectors: 8192

Instead, drop both [fabric,hw]_max_sector checks in sbc_parse_cdb(),
and convert the existing hw_max_sectors into a purely informational
attribute used to represent the granuality that backend driver and/or
subsystem code is splitting I/Os upon.

Also, update FILEIO with an explicit FD_MAX_BYTES check in fd_execute_rw()
to deal with the one special iovec limitiation case.

v2 changes:
  - Drop hw_max_sectors check in sbc_parse_cdb()

Reported-by: default avatarLance Gropper <lance.gropper@qosserver.com>
Reported-by: default avatarStefan Priebe <s.priebe@profihost.ag>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Roland Dreier <roland@purestorage.com>
Cc: stable@vger.kernel.org # 3.4
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent 67e51daa

drivers/target/target_core_device.c

+4 −4
Original line number Diff line number Diff line
@@ -1156,10 +1156,10 @@ int se_dev_set_optimal_sectors(struct se_device *dev, u32 optimal_sectors) 
			dev, dev->export_count);

		return -EINVAL;

	}

	if (optimal_sectors > dev->dev_attrib.fabric_max_sectors) {

	if (optimal_sectors > dev->dev_attrib.hw_max_sectors) {

		pr_err("dev[%p]: Passed optimal_sectors %u cannot be"

			" greater than fabric_max_sectors: %u\n", dev,

			optimal_sectors, dev->dev_attrib.fabric_max_sectors);

			" greater than hw_max_sectors: %u\n", dev,

			optimal_sectors, dev->dev_attrib.hw_max_sectors);

		return -EINVAL;

	}
@@ -1554,7 +1554,6 @@ struct se_device *target_alloc_device(struct se_hba *hba, const char *name) 
				DA_UNMAP_GRANULARITY_ALIGNMENT_DEFAULT;

	dev->dev_attrib.max_write_same_len = DA_MAX_WRITE_SAME_LEN;

	dev->dev_attrib.fabric_max_sectors = DA_FABRIC_MAX_SECTORS;

	dev->dev_attrib.optimal_sectors = DA_FABRIC_MAX_SECTORS;



	xcopy_lun = &dev->xcopy_lun;

	xcopy_lun->lun_se_dev = dev;
@@ -1595,6 +1594,7 @@ int target_configure_device(struct se_device *dev) 
	dev->dev_attrib.hw_max_sectors =

		se_dev_align_max_sectors(dev->dev_attrib.hw_max_sectors,

					 dev->dev_attrib.hw_block_size);

	dev->dev_attrib.optimal_sectors = dev->dev_attrib.hw_max_sectors;



	dev->dev_index = scsi_get_new_index(SCSI_DEVICE_INDEX);

	dev->creation_time = get_jiffies_64();

drivers/target/target_core_file.c

+10 −1
Original line number Diff line number Diff line
@@ -621,7 +621,16 @@ fd_execute_rw(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents, 
	struct fd_prot fd_prot;

	sense_reason_t rc;

	int ret = 0;



	/*

	 * We are currently limited by the number of iovecs (2048) per

	 * single vfs_[writev,readv] call.

	 */

	if (cmd->data_length > FD_MAX_BYTES) {

		pr_err("FILEIO: Not able to process I/O of %u bytes due to"

		       "FD_MAX_BYTES: %u iovec count limitiation\n",

			cmd->data_length, FD_MAX_BYTES);

		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;

	}

	/*

	 * Call vectorized fileio functions to map struct scatterlist

	 * physical memory addresses to struct iovec virtual memory.

drivers/target/target_core_iblock.c

+1 −1
Original line number Diff line number Diff line
@@ -124,7 +124,7 @@ static int iblock_configure_device(struct se_device *dev) 
	q = bdev_get_queue(bd);



	dev->dev_attrib.hw_block_size = bdev_logical_block_size(bd);

	dev->dev_attrib.hw_max_sectors = UINT_MAX;

	dev->dev_attrib.hw_max_sectors = queue_max_hw_sectors(q);

	dev->dev_attrib.hw_queue_depth = q->nr_requests;



	/*

drivers/target/target_core_sbc.c

+0 −15
Original line number Diff line number Diff line
@@ -953,21 +953,6 @@ sbc_parse_cdb(struct se_cmd *cmd, struct sbc_ops *ops) 


	if (cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) {

		unsigned long long end_lba;



		if (sectors > dev->dev_attrib.fabric_max_sectors) {

			printk_ratelimited(KERN_ERR "SCSI OP %02xh with too"

				" big sectors %u exceeds fabric_max_sectors:"

				" %u\n", cdb[0], sectors,

				dev->dev_attrib.fabric_max_sectors);

			return TCM_INVALID_CDB_FIELD;

		}

		if (sectors > dev->dev_attrib.hw_max_sectors) {

			printk_ratelimited(KERN_ERR "SCSI OP %02xh with too"

				" big sectors %u exceeds backend hw_max_sectors:"

				" %u\n", cdb[0], sectors,

				dev->dev_attrib.hw_max_sectors);

			return TCM_INVALID_CDB_FIELD;

		}

check_lba:

		end_lba = dev->transport->get_blocks(dev) + 1;

		if (cmd->t_task_lba + sectors > end_lba) {

drivers/target/target_core_spc.c

+1 −4
Original line number Diff line number Diff line
@@ -505,7 +505,6 @@ static sense_reason_t 
spc_emulate_evpd_b0(struct se_cmd *cmd, unsigned char *buf)

{

	struct se_device *dev = cmd->se_dev;

	u32 max_sectors;

	int have_tp = 0;

	int opt, min;
@@ -539,9 +538,7 @@ spc_emulate_evpd_b0(struct se_cmd *cmd, unsigned char *buf) 
	/*

	 * Set MAXIMUM TRANSFER LENGTH

	 */

	max_sectors = min(dev->dev_attrib.fabric_max_sectors,

			  dev->dev_attrib.hw_max_sectors);

	put_unaligned_be32(max_sectors, &buf[8]);

	put_unaligned_be32(dev->dev_attrib.hw_max_sectors, &buf[8]);



	/*

	 * Set OPTIMAL TRANSFER LENGTH