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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>
This commit is contained in:
Bart Van Assche 2016-02-11 11:08:34 -08:00 committed by Doug Ledford
parent c13c90ea67
commit 8628991fbe
2 changed files with 17 additions and 29 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

42
drivers/infiniband/ulp/srpt/ib_srpt.c
View File

@ -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);
}
/**
@ -1954,11 +1953,11 @@ 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);
@ -2039,7 +2038,7 @@ 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)
@ -2063,7 +2062,7 @@ 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;
@ -2208,9 +2207,9 @@ try_again:
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 @@ static void srpt_refresh_port_work(struct work_struct *work)
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 @@ 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));
list_empty_careful(&sdev->rch_list));
if (res)
pr_err("%s: interrupted.\n", __func__);
@ -2743,7 +2731,7 @@ 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))
@ -2971,12 +2959,12 @@ 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;

4
drivers/infiniband/ulp/srpt/ib_srpt.h
View File

@ -342,7 +342,7 @@ 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 +356,7 @@ 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;