From 8628991fbe6a9086189f55f0b33dee7f25108ecc Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Thu, 11 Feb 2016 11:08:34 -0800 Subject: [PATCH] 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 Reviewed-by: Christoph Hellwig Cc: Sagi Grimberg Cc: Alex Estrin Signed-off-by: Doug Ledford --- drivers/infiniband/ulp/srpt/ib_srpt.c | 42 ++++++++++----------------- drivers/infiniband/ulp/srpt/ib_srpt.h | 4 +-- 2 files changed, 17 insertions(+), 29 deletions(-) diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.c b/drivers/infiniband/ulp/srpt/ib_srpt.c index 0bf204ec443e..33bd408c5eea 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); } /** @@ -1954,11 +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; diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.h b/drivers/infiniband/ulp/srpt/ib_srpt.h index 9c326c71607c..5883295a7b97 100644 --- a/drivers/infiniband/ulp/srpt/ib_srpt.h +++ b/drivers/infiniband/ulp/srpt/ib_srpt.h @@ -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; -- 2.30.2