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Commit 862e6389 authored by Nicholas Bellinger's avatar Nicholas Bellinger
Browse files

target: Add transport_cmd_check_stop write_pending bit 



This patch adds a new transport_cmd_check_stop() parameter for signaling
when TRANSPORT_WRITE_PENDING needs to be set.

This allows transport_generic_new_cmd() to avoid the extra lock acquire/release
of ->t_state_lock in the fast path for DMA_TO_DEVICE operations ahead of
transport_cmd_check_stop() + se_tfo->write_pending().

Cc: Christoph Hellwig <hch@lst.de>
Cc: Roland Dreier <roland@kernel.org>
Cc: Kent Overstreet <koverstreet@google.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: Moussa Ba <moussaba@micron.com>
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent 670caa9f

drivers/target/target_core_transport.c

+9 −10
Original line number Diff line number Diff line
@@ -446,11 +446,15 @@ static void target_remove_from_state_list(struct se_cmd *cmd) 
	spin_unlock_irqrestore(&dev->execute_task_lock, flags);

}



static int transport_cmd_check_stop(struct se_cmd *cmd, bool remove_from_lists)

static int transport_cmd_check_stop(struct se_cmd *cmd, bool remove_from_lists,

				    bool write_pending)

{

	unsigned long flags;



	spin_lock_irqsave(&cmd->t_state_lock, flags);

	if (write_pending)

		cmd->t_state = TRANSPORT_WRITE_PENDING;



	/*

	 * Determine if IOCTL context caller in requesting the stopping of this

	 * command for LUN shutdown purposes.
@@ -515,7 +519,7 @@ static int transport_cmd_check_stop(struct se_cmd *cmd, bool remove_from_lists) 


static int transport_cmd_check_stop_to_fabric(struct se_cmd *cmd)

{

	return transport_cmd_check_stop(cmd, true);

	return transport_cmd_check_stop(cmd, true, false);

}



static void transport_lun_remove_cmd(struct se_cmd *cmd)
@@ -2116,12 +2120,7 @@ transport_generic_new_cmd(struct se_cmd *cmd) 
		target_execute_cmd(cmd);

		return 0;

	}



	spin_lock_irq(&cmd->t_state_lock);

	cmd->t_state = TRANSPORT_WRITE_PENDING;

	spin_unlock_irq(&cmd->t_state_lock);



	transport_cmd_check_stop(cmd, false);

	transport_cmd_check_stop(cmd, false, true);



	ret = cmd->se_tfo->write_pending(cmd);

	if (ret == -EAGAIN || ret == -ENOMEM)
@@ -2319,7 +2318,7 @@ static int transport_lun_wait_for_tasks(struct se_cmd *cmd, struct se_lun *lun) 
		pr_debug("ConfigFS ITT[0x%08x] - CMD_T_STOP, skipping\n",

			 cmd->se_tfo->get_task_tag(cmd));

		spin_unlock_irqrestore(&cmd->t_state_lock, flags);

		transport_cmd_check_stop(cmd, false);

		transport_cmd_check_stop(cmd, false, false);

		return -EPERM;

	}

	cmd->transport_state |= CMD_T_LUN_FE_STOP;
@@ -2427,7 +2426,7 @@ check_cond: 


			spin_unlock_irqrestore(&cmd->t_state_lock,

					cmd_flags);

			transport_cmd_check_stop(cmd, false);

			transport_cmd_check_stop(cmd, false, false);

			complete(&cmd->transport_lun_fe_stop_comp);

			spin_lock_irqsave(&lun->lun_cmd_lock, lun_flags);

			continue;