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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: John Soni Jose <jose0here@gmail.com>
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
This commit is contained in:
Mike Christie 2011-10-06 03:56:57 -05:00 committed by James Bottomley
parent dc55b8274d
commit 8d4a690cd4
2 changed files with 24 additions and 36 deletions
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59
drivers/scsi/scsi_transport_iscsi.c
View File

@ -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);

1
include/scsi/scsi_transport_iscsi.h
View File

@ -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 */