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, protect the list access in
srpt_ch_list_empty() with rcu_read_lock() / rcu_read_unlock().
Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Sagi Grimberg <sagig@xxxxxxxxxxxx>
---
drivers/infiniband/ulp/srpt/ib_srpt.c | 37 ++++++++++++++++++-----------------
drivers/infiniband/ulp/srpt/ib_srpt.h | 5 +++--
2 files changed, 22 insertions(+), 20 deletions(-)
diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.c b/drivers/infiniband/ulp/srpt/ib_srpt.c
index 256b5bf..26aeb0b 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)
*/
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);
}
/**
@@ -1954,15 +1953,15 @@ static void srpt_release_channel_work(struct work_struct *w)
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);
- kfree(ch);
+ kfree_rcu(ch, rcu);
}
/**
@@ -2038,7 +2037,7 @@ static int srpt_cm_req_recv(struct ib_cm_id *cm_id,
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)
@@ -2062,7 +2061,7 @@ static int srpt_cm_req_recv(struct ib_cm_id *cm_id,
}
}
- spin_unlock_irq(&sdev->spinlock);
+ mutex_unlock(&sdev->mutex);
} else
rsp->rsp_flags = SRP_LOGIN_RSP_MULTICHAN_MAINTAINED;
@@ -2203,9 +2202,9 @@ static int srpt_cm_req_recv(struct ib_cm_id *cm_id,
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;
@@ -2651,9 +2650,9 @@ static int srpt_ch_list_empty(struct srpt_device *sdev)
{
int res;
- spin_lock_irq(&sdev->spinlock);
+ rcu_read_lock();
res = list_empty(&sdev->rch_list);
- spin_unlock_irq(&sdev->spinlock);
+ rcu_read_unlock();
return res;
}
@@ -2670,10 +2669,10 @@ static int srpt_release_sdev(struct srpt_device *sdev)
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));
@@ -2737,7 +2736,7 @@ static void srpt_add_one(struct ib_device *device)
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))
@@ -2965,12 +2964,12 @@ static void srpt_close_session(struct se_session *se_sess)
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;
@@ -3380,6 +3379,8 @@ out:
static void __exit srpt_cleanup_module(void)
{
+ rcu_barrier();
+
ib_unregister_client(&srpt_client);
target_unregister_template(&srpt_template);
}
diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.h b/drivers/infiniband/ulp/srpt/ib_srpt.h
index 9c326c7..d1f2877 100644
--- a/drivers/infiniband/ulp/srpt/ib_srpt.h
+++ b/drivers/infiniband/ulp/srpt/ib_srpt.h
@@ -267,6 +267,7 @@ struct srpt_rdma_ch {
struct ib_cm_id *cm_id;
struct ib_qp *qp;
struct ib_cq *cq;
+ struct rcu_head rcu;
int rq_size;
u32 rsp_size;
atomic_t sq_wr_avail;
@@ -342,7 +343,7 @@ struct srpt_port {
* @ioctx_ring: Per-HCA SRQ.
* @rch_list: Per-device channel list -- see also srpt_rdma_ch.list.
* @ch_releaseQ: Enables waiting for removal from rch_list.
- * @spinlock: Protects rch_list and tpg.
+ * @mutex: Protects rch_list.
* @port: Information about the ports owned by this HCA.
* @event_handler: Per-HCA asynchronous IB event handler.
* @list: Node in srpt_dev_list.
@@ -356,7 +357,7 @@ struct srpt_device {
struct srpt_recv_ioctx **ioctx_ring;
struct list_head rch_list;
wait_queue_head_t ch_releaseQ;
- spinlock_t spinlock;
+ struct mutex mutex;
struct srpt_port port[2];
struct ib_event_handler event_handler;
struct list_head list;
--
2.7.0
--
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