From 795bc112cd5a40e7612313f54ee527198b1e734f Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Tue, 16 Jan 2018 16:14:05 -0800 Subject: [PATCH] IB/srpt: Make it safe to use RCU for srpt_device.rch_list The next patch will iterate over rch_list from a context from which it is not allowed to block. Hence make rch_list RCU-safe. Signed-off-by: Bart Van Assche Signed-off-by: Doug Ledford --- drivers/infiniband/ulp/srpt/ib_srpt.c | 13 ++++++++++--- drivers/infiniband/ulp/srpt/ib_srpt.h | 2 ++ 2 files changed, 12 insertions(+), 3 deletions(-) diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.c b/drivers/infiniband/ulp/srpt/ib_srpt.c index d78f60dcc2ba..4dd15378bc7c 100644 --- a/drivers/infiniband/ulp/srpt/ib_srpt.c +++ b/drivers/infiniband/ulp/srpt/ib_srpt.c @@ -1906,7 +1906,7 @@ static void srpt_free_ch(struct kref *kref) { struct srpt_rdma_ch *ch = container_of(kref, struct srpt_rdma_ch, kref); - kfree(ch); + kfree_rcu(ch, rcu); } static void srpt_release_channel_work(struct work_struct *w) @@ -1945,11 +1945,17 @@ static void srpt_release_channel_work(struct work_struct *w) srp_max_req_size, DMA_FROM_DEVICE); mutex_lock(&sdev->mutex); - list_del_init(&ch->list); + list_del_rcu(&ch->list); if (ch->release_done) complete(ch->release_done); mutex_unlock(&sdev->mutex); + synchronize_rcu(); + + mutex_lock(&sdev->mutex); + INIT_LIST_HEAD(&ch->list); + mutex_unlock(&sdev->mutex); + wake_up(&sdev->ch_releaseQ); kref_put(&ch->kref, srpt_free_ch); @@ -2064,6 +2070,7 @@ static int srpt_cm_req_recv(struct ib_cm_id *cm_id, goto reject; } + init_rcu_head(&ch->rcu); kref_init(&ch->kref); ch->zw_cqe.done = srpt_zerolength_write_done; INIT_WORK(&ch->release_work, srpt_release_channel_work); @@ -2190,7 +2197,7 @@ static int srpt_cm_req_recv(struct ib_cm_id *cm_id, } mutex_lock(&sdev->mutex); - list_add_tail(&ch->list, &sdev->rch_list); + list_add_tail_rcu(&ch->list, &sdev->rch_list); mutex_unlock(&sdev->mutex); goto out; diff --git a/drivers/infiniband/ulp/srpt/ib_srpt.h b/drivers/infiniband/ulp/srpt/ib_srpt.h index 11ce8c94a051..0ab59c60f2ef 100644 --- a/drivers/infiniband/ulp/srpt/ib_srpt.h +++ b/drivers/infiniband/ulp/srpt/ib_srpt.h @@ -244,6 +244,7 @@ enum rdma_ch_state { * @qp: IB queue pair used for communicating over this channel. * @cq: IB completion queue for this channel. * @zw_cqe: Zero-length write CQE. + * @rcu: RCU head. * @kref: kref for this channel. * @rq_size: IB receive queue size. * @max_rsp_size: Maximum size of an RSP response message in bytes. @@ -276,6 +277,7 @@ struct srpt_rdma_ch { struct ib_qp *qp; struct ib_cq *cq; struct ib_cqe zw_cqe; + struct rcu_head rcu; struct kref kref; int rq_size; u32 max_rsp_size;