IB/srpt: Use a mutex to protect the channel list
In a later patch a function that can block will be called while
iterating over the rch_list. Hence protect that list with a
mutex instead of a spinlock. And since it is not allowed to sleep
while the task state != TASK_RUNNING, convert the list test in
srpt_ch_list_empty() into a lockless test.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Alex Estrin <alex.estrin@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.c b/drivers/infiniband/ulp/srpt/ib_srpt.c
index 0bf204e..33bd408 100644
--- a/drivers/infiniband/ulp/srpt/ib_srpt.c
+++ b/drivers/infiniband/ulp/srpt/ib_srpt.c
@@ -1862,12 +1862,11 @@
*/
static void srpt_close_ch(struct srpt_rdma_ch *ch)
{
- struct srpt_device *sdev;
+ struct srpt_device *sdev = ch->sport->sdev;
- sdev = ch->sport->sdev;
- spin_lock_irq(&sdev->spinlock);
+ mutex_lock(&sdev->mutex);
__srpt_close_ch(ch);
- spin_unlock_irq(&sdev->spinlock);
+ mutex_unlock(&sdev->mutex);
}
/**
@@ -1954,11 +1953,11 @@
ch->sport->sdev, ch->rq_size,
ch->rsp_size, DMA_TO_DEVICE);
- spin_lock_irq(&sdev->spinlock);
+ mutex_lock(&sdev->mutex);
list_del_init(&ch->list);
if (ch->release_done)
complete(ch->release_done);
- spin_unlock_irq(&sdev->spinlock);
+ mutex_unlock(&sdev->mutex);
wake_up(&sdev->ch_releaseQ);
@@ -2039,7 +2038,7 @@
if ((req->req_flags & SRP_MTCH_ACTION) == SRP_MULTICHAN_SINGLE) {
rsp->rsp_flags = SRP_LOGIN_RSP_MULTICHAN_NO_CHAN;
- spin_lock_irq(&sdev->spinlock);
+ mutex_lock(&sdev->mutex);
list_for_each_entry_safe(ch, tmp_ch, &sdev->rch_list, list) {
if (!memcmp(ch->i_port_id, req->initiator_port_id, 16)
@@ -2063,7 +2062,7 @@
}
}
- spin_unlock_irq(&sdev->spinlock);
+ mutex_unlock(&sdev->mutex);
} else
rsp->rsp_flags = SRP_LOGIN_RSP_MULTICHAN_MAINTAINED;
@@ -2208,9 +2207,9 @@
goto release_channel;
}
- spin_lock_irq(&sdev->spinlock);
+ mutex_lock(&sdev->mutex);
list_add_tail(&ch->list, &sdev->rch_list);
- spin_unlock_irq(&sdev->spinlock);
+ mutex_unlock(&sdev->mutex);
goto out;
@@ -2653,17 +2652,6 @@
srpt_refresh_port(sport);
}
-static int srpt_ch_list_empty(struct srpt_device *sdev)
-{
- int res;
-
- spin_lock_irq(&sdev->spinlock);
- res = list_empty(&sdev->rch_list);
- spin_unlock_irq(&sdev->spinlock);
-
- return res;
-}
-
/**
* srpt_release_sdev() - Free the channel resources associated with a target.
*/
@@ -2676,13 +2664,13 @@
BUG_ON(!sdev);
- spin_lock_irq(&sdev->spinlock);
+ mutex_lock(&sdev->mutex);
list_for_each_entry_safe(ch, tmp_ch, &sdev->rch_list, list)
__srpt_close_ch(ch);
- spin_unlock_irq(&sdev->spinlock);
+ mutex_unlock(&sdev->mutex);
res = wait_event_interruptible(sdev->ch_releaseQ,
- srpt_ch_list_empty(sdev));
+ list_empty_careful(&sdev->rch_list));
if (res)
pr_err("%s: interrupted.\n", __func__);
@@ -2743,7 +2731,7 @@
sdev->device = device;
INIT_LIST_HEAD(&sdev->rch_list);
init_waitqueue_head(&sdev->ch_releaseQ);
- spin_lock_init(&sdev->spinlock);
+ mutex_init(&sdev->mutex);
sdev->pd = ib_alloc_pd(device);
if (IS_ERR(sdev->pd))
@@ -2971,12 +2959,12 @@
pr_debug("ch %s-%d state %d\n", ch->sess_name, ch->qp->qp_num,
ch->state);
- spin_lock_irq(&sdev->spinlock);
+ mutex_lock(&sdev->mutex);
BUG_ON(ch->release_done);
ch->release_done = &release_done;
wait = !list_empty(&ch->list);
__srpt_close_ch(ch);
- spin_unlock_irq(&sdev->spinlock);
+ mutex_unlock(&sdev->mutex);
if (!wait)
return;