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Commit 10e9cbb6 authored by Matthew Wilcox's avatar Matthew Wilcox Committed by Martin K. Petersen
Browse files

scsi: target: Convert target drivers to use sbitmap 

The sbitmap and the percpu_ida perform essentially the same task,
allocating tags for commands.  The sbitmap outperforms the percpu_ida as
documented here: https://lkml.org/lkml/2014/4/22/553



The sbitmap interface is a little harder to use, but being able to remove
the percpu_ida code and getting better performance justifies the additional
complexity.

Signed-off-by: default avatarMatthew Wilcox <willy@infradead.org>
Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com>	# f_tcm
Reviewed-by: default avatarJens Axboe <axboe@kernel.dk>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 83c2b54b

drivers/scsi/qla2xxx/qla_target.c

+6 −4
Original line number Diff line number Diff line
@@ -4277,9 +4277,9 @@ static struct qla_tgt_cmd *qlt_get_tag(scsi_qla_host_t *vha, 
{

	struct se_session *se_sess = sess->se_sess;

	struct qla_tgt_cmd *cmd;

	int tag;

	int tag, cpu;



	tag = percpu_ida_alloc(&se_sess->sess_tag_pool, TASK_RUNNING);

	tag = sbitmap_queue_get(&se_sess->sess_tag_pool, &cpu);

	if (tag < 0)

		return NULL;
@@ -4292,6 +4292,7 @@ static struct qla_tgt_cmd *qlt_get_tag(scsi_qla_host_t *vha, 
	qlt_incr_num_pend_cmds(vha);

	cmd->vha = vha;

	cmd->se_cmd.map_tag = tag;

	cmd->se_cmd.map_cpu = cpu;

	cmd->sess = sess;

	cmd->loop_id = sess->loop_id;

	cmd->conf_compl_supported = sess->conf_compl_supported;
@@ -5294,7 +5295,7 @@ qlt_alloc_qfull_cmd(struct scsi_qla_host *vha, 
	struct fc_port *sess;

	struct se_session *se_sess;

	struct qla_tgt_cmd *cmd;

	int tag;

	int tag, cpu;

	unsigned long flags;



	if (unlikely(tgt->tgt_stop)) {
@@ -5326,7 +5327,7 @@ qlt_alloc_qfull_cmd(struct scsi_qla_host *vha, 


	se_sess = sess->se_sess;



	tag = percpu_ida_alloc(&se_sess->sess_tag_pool, TASK_RUNNING);

	tag = sbitmap_queue_get(&se_sess->sess_tag_pool, &cpu);

	if (tag < 0)

		return;
@@ -5357,6 +5358,7 @@ qlt_alloc_qfull_cmd(struct scsi_qla_host *vha, 
	cmd->reset_count = ha->base_qpair->chip_reset;

	cmd->q_full = 1;

	cmd->qpair = ha->base_qpair;

	cmd->se_cmd.map_cpu = cpu;



	if (qfull) {

		cmd->q_full = 1;

drivers/target/iscsi/iscsi_target_util.c

+30 −3
Original line number Diff line number Diff line
@@ -17,7 +17,7 @@ 
 ******************************************************************************/



#include <linux/list.h>

#include <linux/percpu_ida.h>

#include <linux/sched/signal.h>

#include <net/ipv6.h>         /* ipv6_addr_equal() */

#include <scsi/scsi_tcq.h>

#include <scsi/iscsi_proto.h>
@@ -147,6 +147,30 @@ void iscsit_free_r2ts_from_list(struct iscsi_cmd *cmd) 
	spin_unlock_bh(&cmd->r2t_lock);

}



static int iscsit_wait_for_tag(struct se_session *se_sess, int state, int *cpup)

{

	int tag = -1;

	DEFINE_WAIT(wait);

	struct sbq_wait_state *ws;



	if (state == TASK_RUNNING)

		return tag;



	ws = &se_sess->sess_tag_pool.ws[0];

	for (;;) {

		prepare_to_wait_exclusive(&ws->wait, &wait, state);

		if (signal_pending_state(state, current))

			break;

		tag = sbitmap_queue_get(&se_sess->sess_tag_pool, cpup);

		if (tag >= 0)

			break;

		schedule();

	}



	finish_wait(&ws->wait, &wait);

	return tag;

}



/*

 * May be called from software interrupt (timer) context for allocating

 * iSCSI NopINs.
@@ -155,9 +179,11 @@ struct iscsi_cmd *iscsit_allocate_cmd(struct iscsi_conn *conn, int state) 
{

	struct iscsi_cmd *cmd;

	struct se_session *se_sess = conn->sess->se_sess;

	int size, tag;

	int size, tag, cpu;



	tag = percpu_ida_alloc(&se_sess->sess_tag_pool, state);

	tag = sbitmap_queue_get(&se_sess->sess_tag_pool, &cpu);

	if (tag < 0)

		tag = iscsit_wait_for_tag(se_sess, state, &cpu);

	if (tag < 0)

		return NULL;
@@ -166,6 +192,7 @@ struct iscsi_cmd *iscsit_allocate_cmd(struct iscsi_conn *conn, int state) 
	memset(cmd, 0, size);



	cmd->se_cmd.map_tag = tag;

	cmd->se_cmd.map_cpu = cpu;

	cmd->conn = conn;

	cmd->data_direction = DMA_NONE;

	INIT_LIST_HEAD(&cmd->i_conn_node);

drivers/target/sbp/sbp_target.c

+3 −2
Original line number Diff line number Diff line
@@ -926,15 +926,16 @@ static struct sbp_target_request *sbp_mgt_get_req(struct sbp_session *sess, 
{

	struct se_session *se_sess = sess->se_sess;

	struct sbp_target_request *req;

	int tag;

	int tag, cpu;



	tag = percpu_ida_alloc(&se_sess->sess_tag_pool, TASK_RUNNING);

	tag = sbitmap_queue_get(&se_sess->sess_tag_pool, &cpu);

	if (tag < 0)

		return ERR_PTR(-ENOMEM);



	req = &((struct sbp_target_request *)se_sess->sess_cmd_map)[tag];

	memset(req, 0, sizeof(*req));

	req->se_cmd.map_tag = tag;

	req->se_cmd.map_cpu = cpu;

	req->se_cmd.tag = next_orb;



	return req;

drivers/target/target_core_transport.c

+3 −2
Original line number Diff line number Diff line
@@ -260,7 +260,8 @@ int transport_alloc_session_tags(struct se_session *se_sess, 
		}

	}



	rc = percpu_ida_init(&se_sess->sess_tag_pool, tag_num);

	rc = sbitmap_queue_init_node(&se_sess->sess_tag_pool, tag_num, -1,

			false, GFP_KERNEL, NUMA_NO_NODE);

	if (rc < 0) {

		pr_err("Unable to init se_sess->sess_tag_pool,"

			" tag_num: %u\n", tag_num);
@@ -547,7 +548,7 @@ void transport_free_session(struct se_session *se_sess) 
		target_put_nacl(se_nacl);

	}

	if (se_sess->sess_cmd_map) {

		percpu_ida_destroy(&se_sess->sess_tag_pool);

		sbitmap_queue_free(&se_sess->sess_tag_pool);

		kvfree(se_sess->sess_cmd_map);

	}

	kmem_cache_free(se_sess_cache, se_sess);

drivers/target/tcm_fc/tfc_cmd.c

+3 −3
Original line number Diff line number Diff line
@@ -28,7 +28,6 @@ 
#include <linux/configfs.h>

#include <linux/ctype.h>

#include <linux/hash.h>

#include <linux/percpu_ida.h>

#include <asm/unaligned.h>

#include <scsi/scsi_tcq.h>

#include <scsi/libfc.h>
@@ -448,9 +447,9 @@ static void ft_recv_cmd(struct ft_sess *sess, struct fc_frame *fp) 
	struct ft_cmd *cmd;

	struct fc_lport *lport = sess->tport->lport;

	struct se_session *se_sess = sess->se_sess;

	int tag;

	int tag, cpu;



	tag = percpu_ida_alloc(&se_sess->sess_tag_pool, TASK_RUNNING);

	tag = sbitmap_queue_get(&se_sess->sess_tag_pool, &cpu);

	if (tag < 0)

		goto busy;
@@ -458,6 +457,7 @@ static void ft_recv_cmd(struct ft_sess *sess, struct fc_frame *fp) 
	memset(cmd, 0, sizeof(struct ft_cmd));



	cmd->se_cmd.map_tag = tag;

	cmd->se_cmd.map_cpu = cpu;

	cmd->sess = sess;

	cmd->seq = fc_seq_assign(lport, fp);

	if (!cmd->seq) {