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Commit 015487b8 authored by Roland Dreier's avatar Roland Dreier Committed by Nicholas Bellinger
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target: Untangle front-end and back-end meanings of max_sectors attribute 



se_dev_attrib.max_sectors currently has two independent meanings:

 - It is reported in the block limits VPD page as the maximum transfer
   length, ie the largest IO that the front-end (fabric) can handle.
   Also the target core doesn't enforce this maximum transfer length.

 - It is used to hold the size of the largest IO that the back-end can
   handle, so we know when to split SCSI commands into multiple tasks.

Fix this by adding a new se_dev_attrib.fabric_max_sectors to hold the
maximum transfer length, and checking incoming IOs against that limit.

Signed-off-by: default avatarRoland Dreier <roland@purestorage.com>
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent effc6cc8

drivers/target/target_core_cdb.c

+1 −1
Original line number Diff line number Diff line
@@ -456,7 +456,7 @@ target_emulate_evpd_b0(struct se_cmd *cmd, unsigned char *buf) 
	/*

	 * Set MAXIMUM TRANSFER LENGTH

	 */

	put_unaligned_be32(dev->se_sub_dev->se_dev_attrib.max_sectors, &buf[8]);

	put_unaligned_be32(dev->se_sub_dev->se_dev_attrib.fabric_max_sectors, &buf[8]);



	/*

	 * Set OPTIMAL TRANSFER LENGTH

drivers/target/target_core_configfs.c

+4 −0
Original line number Diff line number Diff line
@@ -702,6 +702,9 @@ SE_DEV_ATTR_RO(hw_max_sectors); 
DEF_DEV_ATTRIB(max_sectors);

SE_DEV_ATTR(max_sectors, S_IRUGO | S_IWUSR);



DEF_DEV_ATTRIB(fabric_max_sectors);

SE_DEV_ATTR(fabric_max_sectors, S_IRUGO | S_IWUSR);



DEF_DEV_ATTRIB(optimal_sectors);

SE_DEV_ATTR(optimal_sectors, S_IRUGO | S_IWUSR);
@@ -741,6 +744,7 @@ static struct configfs_attribute *target_core_dev_attrib_attrs[] = { 
	&target_core_dev_attrib_block_size.attr,

	&target_core_dev_attrib_hw_max_sectors.attr,

	&target_core_dev_attrib_max_sectors.attr,

	&target_core_dev_attrib_fabric_max_sectors.attr,

	&target_core_dev_attrib_optimal_sectors.attr,

	&target_core_dev_attrib_hw_queue_depth.attr,

	&target_core_dev_attrib_queue_depth.attr,

drivers/target/target_core_device.c

+59 −6
Original line number Diff line number Diff line
@@ -889,10 +889,15 @@ void se_dev_set_default_attribs( 
						limits->logical_block_size);

	dev->se_sub_dev->se_dev_attrib.max_sectors = limits->max_sectors;

	/*

	 * Set optimal_sectors from max_sectors, which can be lowered via

	 * configfs.

	 * Set fabric_max_sectors, which is reported in block limits

	 * VPD page (B0h).

	 */

	dev->se_sub_dev->se_dev_attrib.optimal_sectors = limits->max_sectors;

	dev->se_sub_dev->se_dev_attrib.fabric_max_sectors = DA_FABRIC_MAX_SECTORS;

	/*

	 * Set optimal_sectors from fabric_max_sectors, which can be

	 * lowered via configfs.

	 */

	dev->se_sub_dev->se_dev_attrib.optimal_sectors = DA_FABRIC_MAX_SECTORS;

	/*

	 * queue_depth is based on subsystem plugin dependent requirements.

	 */
@@ -1224,6 +1229,54 @@ int se_dev_set_max_sectors(struct se_device *dev, u32 max_sectors) 
	return 0;

}



int se_dev_set_fabric_max_sectors(struct se_device *dev, u32 fabric_max_sectors)

{

	if (atomic_read(&dev->dev_export_obj.obj_access_count)) {

		pr_err("dev[%p]: Unable to change SE Device"

			" fabric_max_sectors while dev_export_obj: %d count exists\n",

			dev, atomic_read(&dev->dev_export_obj.obj_access_count));

		return -EINVAL;

	}

	if (!fabric_max_sectors) {

		pr_err("dev[%p]: Illegal ZERO value for"

			" fabric_max_sectors\n", dev);

		return -EINVAL;

	}

	if (fabric_max_sectors < DA_STATUS_MAX_SECTORS_MIN) {

		pr_err("dev[%p]: Passed fabric_max_sectors: %u less than"

			" DA_STATUS_MAX_SECTORS_MIN: %u\n", dev, fabric_max_sectors,

				DA_STATUS_MAX_SECTORS_MIN);

		return -EINVAL;

	}

	if (dev->transport->transport_type == TRANSPORT_PLUGIN_PHBA_PDEV) {

		if (fabric_max_sectors > dev->se_sub_dev->se_dev_attrib.hw_max_sectors) {

			pr_err("dev[%p]: Passed fabric_max_sectors: %u"

				" greater than TCM/SE_Device max_sectors:"

				" %u\n", dev, fabric_max_sectors,

				dev->se_sub_dev->se_dev_attrib.hw_max_sectors);

			 return -EINVAL;

		}

	} else {

		if (fabric_max_sectors > DA_STATUS_MAX_SECTORS_MAX) {

			pr_err("dev[%p]: Passed fabric_max_sectors: %u"

				" greater than DA_STATUS_MAX_SECTORS_MAX:"

				" %u\n", dev, fabric_max_sectors,

				DA_STATUS_MAX_SECTORS_MAX);

			return -EINVAL;

		}

	}

	/*

	 * Align max_sectors down to PAGE_SIZE to follow transport_allocate_data_tasks()

	 */

	fabric_max_sectors = se_dev_align_max_sectors(fabric_max_sectors,

						      dev->se_sub_dev->se_dev_attrib.block_size);



	dev->se_sub_dev->se_dev_attrib.fabric_max_sectors = fabric_max_sectors;

	pr_debug("dev[%p]: SE Device max_sectors changed to %u\n",

			dev, fabric_max_sectors);

	return 0;

}



int se_dev_set_optimal_sectors(struct se_device *dev, u32 optimal_sectors)

{

	if (atomic_read(&dev->dev_export_obj.obj_access_count)) {
@@ -1237,10 +1290,10 @@ int se_dev_set_optimal_sectors(struct se_device *dev, u32 optimal_sectors) 
				" changed for TCM/pSCSI\n", dev);

		return -EINVAL;

	}

	if (optimal_sectors > dev->se_sub_dev->se_dev_attrib.max_sectors) {

	if (optimal_sectors > dev->se_sub_dev->se_dev_attrib.fabric_max_sectors) {

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

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

			optimal_sectors, dev->se_sub_dev->se_dev_attrib.max_sectors);

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

			optimal_sectors, dev->se_sub_dev->se_dev_attrib.fabric_max_sectors);

		return -EINVAL;

	}

drivers/target/target_core_internal.h

+1 −0
Original line number Diff line number Diff line
@@ -53,6 +53,7 @@ int se_dev_set_is_nonrot(struct se_device *, int); 
int	se_dev_set_emulate_rest_reord(struct se_device *dev, int);

int	se_dev_set_queue_depth(struct se_device *, u32);

int	se_dev_set_max_sectors(struct se_device *, u32);

int	se_dev_set_fabric_max_sectors(struct se_device *, u32);

int	se_dev_set_optimal_sectors(struct se_device *, u32);

int	se_dev_set_block_size(struct se_device *, u32);

struct se_lun *core_dev_add_lun(struct se_portal_group *, struct se_hba *,

drivers/target/target_core_transport.c

+8 −0
Original line number Diff line number Diff line
@@ -37,6 +37,7 @@ 
#include <linux/in.h>

#include <linux/cdrom.h>

#include <linux/module.h>

#include <linux/ratelimit.h>

#include <asm/unaligned.h>

#include <net/sock.h>

#include <net/tcp.h>
@@ -3107,6 +3108,13 @@ static int transport_generic_cmd_sequencer( 
		cmd->data_length = size;

	}



	if (cmd->se_cmd_flags & SCF_SCSI_DATA_SG_IO_CDB &&

	    sectors > dev->se_sub_dev->se_dev_attrib.fabric_max_sectors) {

		printk_ratelimited(KERN_ERR "SCSI OP %02xh with too big sectors %u\n",

				   cdb[0], sectors);

		goto out_invalid_cdb_field;

	}



	/* reject any command that we don't have a handler for */

	if (!(passthrough || cmd->execute_task ||

	     (cmd->se_cmd_flags & SCF_SCSI_DATA_SG_IO_CDB)))