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 <jose0h...@gmail.com>
---
drivers/scsi/scsi_transport_iscsi.c | 56 ++++++++++++----------------------
include/scsi/scsi_transport_iscsi.h | 1 +
2 files changed, 21 insertions(+), 36 deletions(-)
diff --git a/drivers/scsi/scsi_transport_iscsi.c
b/drivers/scsi/scsi_transport_iscsi.c
index b85f8a4..698dcc0 100644
--- a/drivers/scsi/scsi_transport_iscsi.c
+++ b/drivers/scsi/scsi_transport_iscsi.c
@@ -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
@@ -1037,59 +1039,36 @@ 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);
@@ -1101,8 +1080,10 @@ 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);
@@ -1168,6 +1149,9 @@ void iscsi_remove_session(struct iscsi_cls_session
*session)
list_del(&session->sess_list);
spin_unlock_irqrestore(&sesslock, flags);
+ if (session->ida_used)
+ ida_simple_remove(&iscsi_sess_ida, session->target_id);
+
/* make sure there are no blocks/unblocks queued */
flush_workqueue(iscsi_eh_timer_workq);
/* make sure the timedout callout is not running */
diff --git a/include/scsi/scsi_transport_iscsi.h
b/include/scsi/scsi_transport_iscsi.h
index 3389cd5..a498cce 100644
--- a/include/scsi/scsi_transport_iscsi.h
+++ b/include/scsi/scsi_transport_iscsi.h
@@ -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 */
--
1.7.6.178.g55272
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