IB/srp: Change target_mutex to a spinlock
The SRP driver never sleeps while holding target_mutex, and it's just
used to protect some simple list operations, so hold times will be
short. So just convert it to a spinlock, which is smaller and faster.
Signed-off-by: Matthew Wilcox <matthew@wil.cx>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
diff --git a/drivers/infiniband/ulp/srp/ib_srp.c b/drivers/infiniband/ulp/srp/ib_srp.c
index 7c0a3d9..ae1ab6a 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.c
+++ b/drivers/infiniband/ulp/srp/ib_srp.c
@@ -361,9 +361,9 @@
target->state = SRP_TARGET_REMOVED;
spin_unlock_irq(target->scsi_host->host_lock);
- mutex_lock(&target->srp_host->target_mutex);
+ spin_lock(&target->srp_host->target_lock);
list_del(&target->list);
- mutex_unlock(&target->srp_host->target_mutex);
+ spin_unlock(&target->srp_host->target_lock);
scsi_remove_host(target->scsi_host);
ib_destroy_cm_id(target->cm_id);
@@ -1450,9 +1450,9 @@
if (scsi_add_host(target->scsi_host, host->dev->dev->dma_device))
return -ENODEV;
- mutex_lock(&host->target_mutex);
+ spin_lock(&host->target_lock);
list_add_tail(&target->list, &host->target_list);
- mutex_unlock(&host->target_mutex);
+ spin_unlock(&host->target_lock);
target->state = SRP_TARGET_LIVE;
@@ -1724,7 +1724,7 @@
return NULL;
INIT_LIST_HEAD(&host->target_list);
- mutex_init(&host->target_mutex);
+ spin_lock_init(&host->target_lock);
init_completion(&host->released);
host->dev = device;
host->port = port;
@@ -1866,14 +1866,14 @@
* Mark all target ports as removed, so we stop queueing
* commands and don't try to reconnect.
*/
- mutex_lock(&host->target_mutex);
+ spin_lock(&host->target_lock);
list_for_each_entry(target, &host->target_list, list) {
spin_lock_irqsave(target->scsi_host->host_lock, flags);
if (target->state != SRP_TARGET_REMOVED)
target->state = SRP_TARGET_REMOVED;
spin_unlock_irqrestore(target->scsi_host->host_lock, flags);
}
- mutex_unlock(&host->target_mutex);
+ spin_unlock(&host->target_lock);
/*
* Wait for any reconnection tasks that may have
diff --git a/drivers/infiniband/ulp/srp/ib_srp.h b/drivers/infiniband/ulp/srp/ib_srp.h
index 5ecda4a..c071c30 100644
--- a/drivers/infiniband/ulp/srp/ib_srp.h
+++ b/drivers/infiniband/ulp/srp/ib_srp.h
@@ -99,7 +99,7 @@
u8 port;
struct class_device class_dev;
struct list_head target_list;
- struct mutex target_mutex;
+ spinlock_t target_lock;
struct completion released;
struct list_head list;
};