target: Remove max_sectors device attribute for modern se_task less code

This patch removes the original usage of dev_attr->max_sectors in favor of
dev_attr->hw_max_sectors that is now being enforced by target core from
within transport_generic_cmd_sequencer() for SCF_SCSI_DATA_SG_IO_CDB ops.

After the recent se_task removal patches from hch, this value for IBLOCK
backends being set via configfs by userspace from an saved max_sectors
value that is turning out to be problematic, so it makes sense to go ahead
and remove this now legacy attribute all-together.

This patch also continues to make se_dev_set_default_attribs() do
(sectors / block_size) alignment for what actually get used by
target_core_mod to be safe here, following the same alignment currently
used by fabric_max_sectors.

Reported-by: Andy Grover <agrover@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Roland Dreier <roland@purestorage.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/target/target_core_cdb.c

@@ -458,7 +458,7 @@ target_emulate_evpd_b0(struct se_cmd *cmd, unsigned char *buf)
 	 * Set MAXIMUM TRANSFER LENGTH
 	 */
 	max_sectors = min(dev->se_sub_dev->se_dev_attrib.fabric_max_sectors,
-			  dev->se_sub_dev->se_dev_attrib.max_sectors);
+			  dev->se_sub_dev->se_dev_attrib.hw_max_sectors);
 	put_unaligned_be32(max_sectors, &buf[8]);
 
 	/*

drivers/target/target_core_configfs.c

@@ -683,9 +683,6 @@ SE_DEV_ATTR(block_size, S_IRUGO | S_IWUSR);
 DEF_DEV_ATTRIB_RO(hw_max_sectors);
 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);
 
@@ -727,7 +724,6 @@ static struct configfs_attribute *target_core_dev_attrib_attrs[] = {
 	&target_core_dev_attrib_hw_block_size.attr,
 	&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,

drivers/target/target_core_device.c

@@ -876,15 +876,12 @@ void se_dev_set_default_attribs(
 	dev->se_sub_dev->se_dev_attrib.hw_block_size = limits->logical_block_size;
 	dev->se_sub_dev->se_dev_attrib.block_size = limits->logical_block_size;
 	/*
-	 * max_sectors is based on subsystem plugin dependent requirements.
+	 * Align max_hw_sectors down to PAGE_SIZE I/O transfers
 	 */
-	dev->se_sub_dev->se_dev_attrib.hw_max_sectors = limits->max_hw_sectors;
-	/*
-	 * Align max_sectors down to PAGE_SIZE to follow transport_allocate_data_tasks()
-	 */
-	limits->max_sectors = se_dev_align_max_sectors(limits->max_sectors,
+	limits->max_hw_sectors = se_dev_align_max_sectors(limits->max_hw_sectors,
 						limits->logical_block_size);
-	dev->se_sub_dev->se_dev_attrib.max_sectors = limits->max_sectors;
+	dev->se_sub_dev->se_dev_attrib.hw_max_sectors = limits->max_hw_sectors;
+
 	/*
 	 * Set fabric_max_sectors, which is reported in block limits
 	 * VPD page (B0h).
@@ -1168,64 +1165,6 @@ int se_dev_set_queue_depth(struct se_device *dev, u32 queue_depth)
 	return 0;
 }
 
-int se_dev_set_max_sectors(struct se_device *dev, u32 max_sectors)
-{
-	int force = 0; /* Force setting for VDEVS */
-
-	if (atomic_read(&dev->dev_export_obj.obj_access_count)) {
-		pr_err("dev[%p]: Unable to change SE Device"
-			" max_sectors while dev_export_obj: %d count exists\n",
-			dev, atomic_read(&dev->dev_export_obj.obj_access_count));
-		return -EINVAL;
-	}
-	if (!max_sectors) {
-		pr_err("dev[%p]: Illegal ZERO value for"
-			" max_sectors\n", dev);
-		return -EINVAL;
-	}
-	if (max_sectors < DA_STATUS_MAX_SECTORS_MIN) {
-		pr_err("dev[%p]: Passed max_sectors: %u less than"
-			" DA_STATUS_MAX_SECTORS_MIN: %u\n", dev, max_sectors,
-				DA_STATUS_MAX_SECTORS_MIN);
-		return -EINVAL;
-	}
-	if (dev->transport->transport_type == TRANSPORT_PLUGIN_PHBA_PDEV) {
-		if (max_sectors > dev->se_sub_dev->se_dev_attrib.hw_max_sectors) {
-			pr_err("dev[%p]: Passed max_sectors: %u"
-				" greater than TCM/SE_Device max_sectors:"
-				" %u\n", dev, max_sectors,
-				dev->se_sub_dev->se_dev_attrib.hw_max_sectors);
-			 return -EINVAL;
-		}
-	} else {
-		if (!force && (max_sectors >
-				 dev->se_sub_dev->se_dev_attrib.hw_max_sectors)) {
-			pr_err("dev[%p]: Passed max_sectors: %u"
-				" greater than TCM/SE_Device max_sectors"
-				": %u, use force=1 to override.\n", dev,
-				max_sectors, dev->se_sub_dev->se_dev_attrib.hw_max_sectors);
-			return -EINVAL;
-		}
-		if (max_sectors > DA_STATUS_MAX_SECTORS_MAX) {
-			pr_err("dev[%p]: Passed max_sectors: %u"
-				" greater than DA_STATUS_MAX_SECTORS_MAX:"
-				" %u\n", dev, max_sectors,
-				DA_STATUS_MAX_SECTORS_MAX);
-			return -EINVAL;
-		}
-	}
-	/*
-	 * Align max_sectors down to PAGE_SIZE to follow transport_allocate_data_tasks()
-	 */
-	max_sectors = se_dev_align_max_sectors(max_sectors,
-				dev->se_sub_dev->se_dev_attrib.block_size);
-
-	dev->se_sub_dev->se_dev_attrib.max_sectors = max_sectors;
-	pr_debug("dev[%p]: SE Device max_sectors changed to %u\n",
-			dev, 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)) {

drivers/target/target_core_transport.c

@@ -870,8 +870,9 @@ void transport_dump_dev_state(
 
 	*bl += sprintf(b + *bl, "  Execute/Max Queue Depth: %d/%d",
 		atomic_read(&dev->execute_tasks), dev->queue_depth);
-	*bl += sprintf(b + *bl, "  SectorSize: %u  MaxSectors: %u\n",
-		dev->se_sub_dev->se_dev_attrib.block_size, dev->se_sub_dev->se_dev_attrib.max_sectors);
+	*bl += sprintf(b + *bl, "  SectorSize: %u  HwMaxSectors: %u\n",
+		dev->se_sub_dev->se_dev_attrib.block_size,
+		dev->se_sub_dev->se_dev_attrib.hw_max_sectors);
 	*bl += sprintf(b + *bl, "        ");
 }
 
@@ -3498,7 +3499,7 @@ int transport_generic_new_cmd(struct se_cmd *cmd)
 
 		BUG_ON(cmd->data_length % attr->block_size);
 		BUG_ON(DIV_ROUND_UP(cmd->data_length, attr->block_size) >
-			attr->max_sectors);
+			attr->hw_max_sectors);
 	}
 
 	atomic_inc(&cmd->t_fe_count);

include/target/target_core_base.h

@@ -708,7 +708,6 @@ struct se_dev_attrib {
 	u32		hw_block_size;
 	u32		block_size;
 	u32		hw_max_sectors;
-	u32		max_sectors;
 	u32		fabric_max_sectors;
 	u32		optimal_sectors;
 	u32		hw_queue_depth;