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Commit 8d4a690c authored by Mike Christie's avatar Mike Christie Committed by James Bottomley
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[SCSI] iscsi class: Replace iscsi_get_next_target_id with IDA 



 Replaced the iscsi_get_next_target_id with IDA to make
 target-id allocation efficient for iscsi offload drivers

 This patch should be applied after Jonathen Cameron Patch
 "ida : simplified functions for id allocation"

Signed-off-by: default avatarJohn Soni Jose <jose0here@gmail.com>
Signed-off-by: default avatarMike Christie <michaelc@cs.wisc.edu>
Signed-off-by: default avatarJames Bottomley <JBottomley@Parallels.com>
parent dc55b827

drivers/scsi/scsi_transport_iscsi.c

+23 −36
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ 
#include <linux/mutex.h>

#include <linux/slab.h>

#include <linux/bsg-lib.h>

#include <linux/idr.h>

#include <net/tcp.h>

#include <scsi/scsi.h>

#include <scsi/scsi_host.h>
@@ -81,6 +82,7 @@ struct iscsi_internal { 
static atomic_t iscsi_session_nr; /* sysfs session id for next new session */

static struct workqueue_struct *iscsi_eh_timer_workq;



static DEFINE_IDA(iscsi_sess_ida);

/*

 * list of registered transports and lock that must

 * be held while accessing list. The iscsi_transport_lock must
@@ -990,6 +992,7 @@ static void __iscsi_unbind_session(struct work_struct *work) 
	struct Scsi_Host *shost = iscsi_session_to_shost(session);

	struct iscsi_cls_host *ihost = shost->shost_data;

	unsigned long flags;

	unsigned int target_id;



	ISCSI_DBG_TRANS_SESSION(session, "Unbinding session\n");
@@ -1001,10 +1004,15 @@ static void __iscsi_unbind_session(struct work_struct *work) 
		mutex_unlock(&ihost->mutex);

		return;

	}



	target_id = session->target_id;

	session->target_id = ISCSI_MAX_TARGET;

	spin_unlock_irqrestore(&session->lock, flags);

	mutex_unlock(&ihost->mutex);



	if (session->ida_used)

		ida_simple_remove(&iscsi_sess_ida, target_id);



	scsi_remove_target(&session->dev);

	iscsi_session_event(session, ISCSI_KEVENT_UNBIND_SESSION);

	ISCSI_DBG_TRANS_SESSION(session, "Completed target removal\n");
@@ -1045,59 +1053,36 @@ iscsi_alloc_session(struct Scsi_Host *shost, struct iscsi_transport *transport, 
}

EXPORT_SYMBOL_GPL(iscsi_alloc_session);



static int iscsi_get_next_target_id(struct device *dev, void *data)

{

	struct iscsi_cls_session *session;

	unsigned long flags;

	int err = 0;



	if (!iscsi_is_session_dev(dev))

		return 0;



	session = iscsi_dev_to_session(dev);

	spin_lock_irqsave(&session->lock, flags);

	if (*((unsigned int *) data) == session->target_id)

		err = -EEXIST;

	spin_unlock_irqrestore(&session->lock, flags);

	return err;

}



int iscsi_add_session(struct iscsi_cls_session *session, unsigned int target_id)

{

	struct Scsi_Host *shost = iscsi_session_to_shost(session);

	struct iscsi_cls_host *ihost;

	unsigned long flags;

	unsigned int id = target_id;

	int id = 0;

	int err;



	ihost = shost->shost_data;

	session->sid = atomic_add_return(1, &iscsi_session_nr);



	if (id == ISCSI_MAX_TARGET) {

		for (id = 0; id < ISCSI_MAX_TARGET; id++) {

			err = device_for_each_child(&shost->shost_gendev, &id,

						    iscsi_get_next_target_id);

			if (!err)

				break;

		}

	if (target_id == ISCSI_MAX_TARGET) {

		id = ida_simple_get(&iscsi_sess_ida, 0, 0, GFP_KERNEL);



		if (id == ISCSI_MAX_TARGET) {

		if (id < 0) {

			iscsi_cls_session_printk(KERN_ERR, session,

						 "Too many iscsi targets. Max "

						 "number of targets is %d.\n",

						 ISCSI_MAX_TARGET - 1);

			err = -EOVERFLOW;

			goto release_host;

					"Failure in Target ID Allocation\n");

			return id;

		}

	}

	session->target_id = id;

		session->target_id = (unsigned int)id;

		session->ida_used = true;

	} else

		session->target_id = target_id;



	dev_set_name(&session->dev, "session%u", session->sid);

	err = device_add(&session->dev);

	if (err) {

		iscsi_cls_session_printk(KERN_ERR, session,

					 "could not register session's dev\n");

		goto release_host;

		goto release_ida;

	}

	transport_register_device(&session->dev);
@@ -1109,8 +1094,10 @@ int iscsi_add_session(struct iscsi_cls_session *session, unsigned int target_id) 
	ISCSI_DBG_TRANS_SESSION(session, "Completed session adding\n");

	return 0;



release_host:

	scsi_host_put(shost);

release_ida:

	if (session->ida_used)

		ida_simple_remove(&iscsi_sess_ida, session->target_id);



	return err;

}

EXPORT_SYMBOL_GPL(iscsi_add_session);

include/scsi/scsi_transport_iscsi.h

+1 −0
Original line number Diff line number Diff line
@@ -208,6 +208,7 @@ struct iscsi_cls_session { 
	struct delayed_work recovery_work;



	unsigned int target_id;

	bool ida_used;



	int state;

	int sid;				/* session id */