SVCRDMA: Add xprt refs to fix close/unmount crash
RDMA connection shutdown on an SMP machine can cause a kernel crash due to the transport close path racing with the I/O tasklet. Additional transport references were added as follows: - A reference when on the DTO Q to avoid having the transport deleted while queued for I/O. - A reference while there is a QP able to generate events. - A reference until the DISCONNECTED event is received on the CM ID Signed-off-by: Tom Tucker <tom@opengridcomputing.com> Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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ee27a558ae
commit
c48cbb405c
1 changed files with 62 additions and 42 deletions
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@ -54,7 +54,6 @@ static struct svc_xprt *svc_rdma_create(struct svc_serv *serv,
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int flags);
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static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt);
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static void svc_rdma_release_rqst(struct svc_rqst *);
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static void rdma_destroy_xprt(struct svcxprt_rdma *xprt);
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static void dto_tasklet_func(unsigned long data);
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static void svc_rdma_detach(struct svc_xprt *xprt);
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static void svc_rdma_free(struct svc_xprt *xprt);
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@ -247,6 +246,7 @@ static void dto_tasklet_func(unsigned long data)
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sq_cq_reap(xprt);
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}
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svc_xprt_put(&xprt->sc_xprt);
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spin_lock_irqsave(&dto_lock, flags);
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}
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spin_unlock_irqrestore(&dto_lock, flags);
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@ -275,8 +275,10 @@ static void rq_comp_handler(struct ib_cq *cq, void *cq_context)
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* add it
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*/
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spin_lock_irqsave(&dto_lock, flags);
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if (list_empty(&xprt->sc_dto_q))
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if (list_empty(&xprt->sc_dto_q)) {
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svc_xprt_get(&xprt->sc_xprt);
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list_add_tail(&xprt->sc_dto_q, &dto_xprt_q);
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}
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spin_unlock_irqrestore(&dto_lock, flags);
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/* Tasklet does all the work to avoid irqsave locks. */
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@ -386,8 +388,10 @@ static void sq_comp_handler(struct ib_cq *cq, void *cq_context)
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* add it
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*/
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spin_lock_irqsave(&dto_lock, flags);
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if (list_empty(&xprt->sc_dto_q))
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if (list_empty(&xprt->sc_dto_q)) {
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svc_xprt_get(&xprt->sc_xprt);
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list_add_tail(&xprt->sc_dto_q, &dto_xprt_q);
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}
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spin_unlock_irqrestore(&dto_lock, flags);
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/* Tasklet does all the work to avoid irqsave locks. */
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@ -611,6 +615,7 @@ static int rdma_cma_handler(struct rdma_cm_id *cma_id,
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switch (event->event) {
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case RDMA_CM_EVENT_ESTABLISHED:
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/* Accept complete */
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svc_xprt_get(xprt);
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dprintk("svcrdma: Connection completed on DTO xprt=%p, "
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"cm_id=%p\n", xprt, cma_id);
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clear_bit(RDMAXPRT_CONN_PENDING, &rdma->sc_flags);
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@ -661,15 +666,15 @@ static struct svc_xprt *svc_rdma_create(struct svc_serv *serv,
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listen_id = rdma_create_id(rdma_listen_handler, cma_xprt, RDMA_PS_TCP);
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if (IS_ERR(listen_id)) {
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rdma_destroy_xprt(cma_xprt);
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svc_xprt_put(&cma_xprt->sc_xprt);
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dprintk("svcrdma: rdma_create_id failed = %ld\n",
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PTR_ERR(listen_id));
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return (void *)listen_id;
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}
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ret = rdma_bind_addr(listen_id, sa);
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if (ret) {
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rdma_destroy_xprt(cma_xprt);
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rdma_destroy_id(listen_id);
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svc_xprt_put(&cma_xprt->sc_xprt);
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dprintk("svcrdma: rdma_bind_addr failed = %d\n", ret);
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return ERR_PTR(ret);
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}
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@ -678,8 +683,9 @@ static struct svc_xprt *svc_rdma_create(struct svc_serv *serv,
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ret = rdma_listen(listen_id, RPCRDMA_LISTEN_BACKLOG);
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if (ret) {
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rdma_destroy_id(listen_id);
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rdma_destroy_xprt(cma_xprt);
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svc_xprt_put(&cma_xprt->sc_xprt);
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dprintk("svcrdma: rdma_listen failed = %d\n", ret);
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return ERR_PTR(ret);
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}
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/*
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@ -820,6 +826,7 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
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newxprt->sc_sq_depth = qp_attr.cap.max_send_wr;
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newxprt->sc_max_requests = qp_attr.cap.max_recv_wr;
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}
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svc_xprt_get(&newxprt->sc_xprt);
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newxprt->sc_qp = newxprt->sc_cm_id->qp;
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/* Register all of physical memory */
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@ -891,8 +898,15 @@ static struct svc_xprt *svc_rdma_accept(struct svc_xprt *xprt)
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errout:
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dprintk("svcrdma: failure accepting new connection rc=%d.\n", ret);
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/* Take a reference in case the DTO handler runs */
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svc_xprt_get(&newxprt->sc_xprt);
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if (newxprt->sc_qp && !IS_ERR(newxprt->sc_qp)) {
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ib_destroy_qp(newxprt->sc_qp);
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svc_xprt_put(&newxprt->sc_xprt);
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}
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rdma_destroy_id(newxprt->sc_cm_id);
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rdma_destroy_xprt(newxprt);
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/* This call to put will destroy the transport */
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svc_xprt_put(&newxprt->sc_xprt);
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return NULL;
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}
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@ -919,56 +933,62 @@ static void svc_rdma_release_rqst(struct svc_rqst *rqstp)
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rqstp->rq_xprt_ctxt = NULL;
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}
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/* Disable data ready events for this connection */
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/*
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* When connected, an svc_xprt has at least three references:
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*
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* - A reference held by the QP. We still hold that here because this
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* code deletes the QP and puts the reference.
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*
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* - A reference held by the cm_id between the ESTABLISHED and
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* DISCONNECTED events. If the remote peer disconnected first, this
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* reference could be gone.
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*
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* - A reference held by the svc_recv code that called this function
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* as part of close processing.
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*
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* At a minimum two references should still be held.
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*/
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static void svc_rdma_detach(struct svc_xprt *xprt)
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{
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struct svcxprt_rdma *rdma =
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container_of(xprt, struct svcxprt_rdma, sc_xprt);
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unsigned long flags;
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dprintk("svc: svc_rdma_detach(%p)\n", xprt);
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/*
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* Shutdown the connection. This will ensure we don't get any
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* more events from the provider.
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*/
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rdma_disconnect(rdma->sc_cm_id);
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rdma_destroy_id(rdma->sc_cm_id);
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/* We may already be on the DTO list */
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spin_lock_irqsave(&dto_lock, flags);
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if (!list_empty(&rdma->sc_dto_q))
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list_del_init(&rdma->sc_dto_q);
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spin_unlock_irqrestore(&dto_lock, flags);
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/* Disconnect and flush posted WQE */
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rdma_disconnect(rdma->sc_cm_id);
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/* Destroy the QP if present (not a listener) */
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if (rdma->sc_qp && !IS_ERR(rdma->sc_qp)) {
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ib_destroy_qp(rdma->sc_qp);
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svc_xprt_put(xprt);
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}
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/* Destroy the CM ID */
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rdma_destroy_id(rdma->sc_cm_id);
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}
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static void svc_rdma_free(struct svc_xprt *xprt)
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{
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struct svcxprt_rdma *rdma = (struct svcxprt_rdma *)xprt;
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dprintk("svcrdma: svc_rdma_free(%p)\n", rdma);
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rdma_destroy_xprt(rdma);
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/* We should only be called from kref_put */
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BUG_ON(atomic_read(&xprt->xpt_ref.refcount) != 0);
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if (rdma->sc_sq_cq && !IS_ERR(rdma->sc_sq_cq))
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ib_destroy_cq(rdma->sc_sq_cq);
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if (rdma->sc_rq_cq && !IS_ERR(rdma->sc_rq_cq))
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ib_destroy_cq(rdma->sc_rq_cq);
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if (rdma->sc_phys_mr && !IS_ERR(rdma->sc_phys_mr))
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ib_dereg_mr(rdma->sc_phys_mr);
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if (rdma->sc_pd && !IS_ERR(rdma->sc_pd))
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ib_dealloc_pd(rdma->sc_pd);
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destroy_context_cache(rdma->sc_ctxt_head);
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kfree(rdma);
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}
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static void rdma_destroy_xprt(struct svcxprt_rdma *xprt)
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{
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if (xprt->sc_qp && !IS_ERR(xprt->sc_qp))
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ib_destroy_qp(xprt->sc_qp);
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if (xprt->sc_sq_cq && !IS_ERR(xprt->sc_sq_cq))
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ib_destroy_cq(xprt->sc_sq_cq);
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if (xprt->sc_rq_cq && !IS_ERR(xprt->sc_rq_cq))
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ib_destroy_cq(xprt->sc_rq_cq);
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if (xprt->sc_phys_mr && !IS_ERR(xprt->sc_phys_mr))
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ib_dereg_mr(xprt->sc_phys_mr);
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if (xprt->sc_pd && !IS_ERR(xprt->sc_pd))
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ib_dealloc_pd(xprt->sc_pd);
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destroy_context_cache(xprt->sc_ctxt_head);
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}
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static int svc_rdma_has_wspace(struct svc_xprt *xprt)
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{
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struct svcxprt_rdma *rdma =
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