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 <bart.vanassche@wdc.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
This commit is contained in:
Bart Van Assche 2018-01-16 16:14:05 -08:00 committed by Doug Ledford
parent 48900a2834
commit 795bc112cd
2 changed files with 12 additions and 3 deletions

View File

@ -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;

View File

@ -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;