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SVCRDMA: Add xprt refs to fix close/unmount crash

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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>
This commit is contained in:
Tom Tucker 2008-03-11 14:31:39 -04:00 committed by Linus Torvalds
parent ee27a558ae
commit c48cbb405c
1 changed files with 62 additions and 42 deletions
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104
net/sunrpc/xprtrdma/svc_rdma_transport.c
View file

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