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Commit 695434e1 authored by Nicholas Bellinger's avatar Nicholas Bellinger
Browse files

target: Add transport_handle_cdb_direct optimization 



This patch adds a transport_handle_cdb_direct() optimization for mapping
and queueing tasks directly from within fabric processing context by calling
the newly exported transport_generic_new_cmd().  This currently expects to
be called from process context only, and will fail if called within interrupt
context.

This patch also leaves transport_generic_handle_cdb() unmodified for the
moment to function as expected with existing tcm_fc and ib_srpt fabrics,
and will be removed once these have been converted and tested with v4.1
code using transport_handle_cdb_direct().

Based on Andy's original patch here:

[PATCH 39/42] target: Call transport_new_cmd instead of adding to cmd queue

Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent 35462975

drivers/target/target_core_transport.c

+24 −0
Original line number Diff line number Diff line
@@ -1842,11 +1842,35 @@ int transport_generic_handle_cdb( 
		printk(KERN_ERR "cmd->se_lun is NULL\n");

		return -EINVAL;

	}



	transport_add_cmd_to_queue(cmd, TRANSPORT_NEW_CMD);

	return 0;

}

EXPORT_SYMBOL(transport_generic_handle_cdb);



/*

 * Used by fabric module frontends to queue tasks directly.

 * Many only be used from process context only

 */

int transport_handle_cdb_direct(

	struct se_cmd *cmd)

{

	if (!cmd->se_lun) {

		dump_stack();

		printk(KERN_ERR "cmd->se_lun is NULL\n");

		return -EINVAL;

	}

	if (in_interrupt()) {

		dump_stack();

		printk(KERN_ERR "transport_generic_handle_cdb cannot be called"

				" from interrupt context\n");

		return -EINVAL;

	}



	return transport_generic_new_cmd(cmd);

}

EXPORT_SYMBOL(transport_handle_cdb_direct);



/*

 * Used by fabric module frontends defining a TFO->new_cmd_map() caller

 * to  queue up a newly setup se_cmd w/ TRANSPORT_NEW_CMD_MAP in order to

include/target/target_core_transport.h

+1 −0
Original line number Diff line number Diff line
@@ -166,6 +166,7 @@ extern void transport_init_se_cmd(struct se_cmd *, 
extern void transport_free_se_cmd(struct se_cmd *);

extern int transport_generic_allocate_tasks(struct se_cmd *, unsigned char *);

extern int transport_generic_handle_cdb(struct se_cmd *);

extern int transport_handle_cdb_direct(struct se_cmd *);

extern int transport_generic_handle_cdb_map(struct se_cmd *);

extern int transport_generic_handle_data(struct se_cmd *);

extern void transport_new_cmd_failure(struct se_cmd *);