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xprtrdma: Support unplugging an HCA from under an NFS mount 

The device driver for the underlying physical device associated
with an RPC-over-RDMA transport can be removed while RPC-over-RDMA
transports are still in use (ie, while NFS filesystems are still
mounted and active). The IB core performs a connection event upcall
to request that consumers free all RDMA resources associated with
a transport.

There may be pending RPCs when this occurs. Care must be taken to
release associated resources without leaving references that can
trigger a subsequent crash if a signal or soft timeout occurs. We
rely on the caller of the transport's ->close method to ensure that
the previous RPC task has invoked xprt_release but the transport
remains write-locked.

A DEVICE_REMOVE upcall forces a disconnect then sleeps. When ->close
is invoked, it destroys the transport's H/W resources, then wakes
the upcall, which completes and allows the core driver unload to
continue.

BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=266
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
zero-colors
Chuck Lever 2017-04-11 13:23:10 -04:00 committed by Anna Schumaker
parent 91a10c5297
commit bebd031866
3 changed files with 101 additions and 9 deletions
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29
net/sunrpc/xprtrdma/transport.c
View File

@ -457,19 +457,33 @@ out1:
return ERR_PTR(rc);
}
/*
* Close a connection, during shutdown or timeout/reconnect
/**
* xprt_rdma_close - Close down RDMA connection
* @xprt: generic transport to be closed
*
* Called during transport shutdown reconnect, or device
* removal. Caller holds the transport's write lock.
*/
static void
xprt_rdma_close(struct rpc_xprt *xprt)
{
struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
struct rpcrdma_ep *ep = &r_xprt->rx_ep;
struct rpcrdma_ia *ia = &r_xprt->rx_ia;
dprintk("RPC: %s: closing\n", __func__);
if (r_xprt->rx_ep.rep_connected > 0)
dprintk("RPC: %s: closing xprt %p\n", __func__, xprt);
if (test_and_clear_bit(RPCRDMA_IAF_REMOVING, &ia->ri_flags)) {
xprt_clear_connected(xprt);
rpcrdma_ia_remove(ia);
return;
}
if (ep->rep_connected == -ENODEV)
return;
if (ep->rep_connected > 0)
xprt->reestablish_timeout = 0;
xprt_disconnect_done(xprt);
rpcrdma_ep_disconnect(&r_xprt->rx_ep, &r_xprt->rx_ia);
rpcrdma_ep_disconnect(ep, ia);
}
static void
@ -680,6 +694,8 @@ xprt_rdma_free(struct rpc_task *task)
* xprt_rdma_send_request - marshal and send an RPC request
* @task: RPC task with an RPC message in rq_snd_buf
*
* Caller holds the transport's write lock.
*
* Return values:
* 0: The request has been sent
* ENOTCONN: Caller needs to invoke connect logic then call again
@ -706,6 +722,9 @@ xprt_rdma_send_request(struct rpc_task *task)
struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
int rc = 0;
if (!xprt_connected(xprt))
goto drop_connection;
/* On retransmit, remove any previously registered chunks */
if (unlikely(!list_empty(&req->rl_registered)))
r_xprt->rx_ia.ri_ops->ro_unmap_safe(r_xprt, req, false);

74
net/sunrpc/xprtrdma/verbs.c
View File

@ -69,6 +69,8 @@
/*
* internal functions
*/
static void rpcrdma_destroy_mrs(struct rpcrdma_buffer *buf);
static void rpcrdma_dma_unmap_regbuf(struct rpcrdma_regbuf *rb);
static struct workqueue_struct *rpcrdma_receive_wq;
@ -262,6 +264,21 @@ rpcrdma_conn_upcall(struct rdma_cm_id *id, struct rdma_cm_event *event)
__func__, ep);
complete(&ia->ri_done);
break;
case RDMA_CM_EVENT_DEVICE_REMOVAL:
#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
pr_info("rpcrdma: removing device for %pIS:%u\n",
sap, rpc_get_port(sap));
#endif
set_bit(RPCRDMA_IAF_REMOVING, &ia->ri_flags);
ep->rep_connected = -ENODEV;
xprt_force_disconnect(&xprt->rx_xprt);
wait_for_completion(&ia->ri_remove_done);
ia->ri_id = NULL;
ia->ri_pd = NULL;
ia->ri_device = NULL;
/* Return 1 to ensure the core destroys the id. */
return 1;
case RDMA_CM_EVENT_ESTABLISHED:
connstate = 1;
ib_query_qp(ia->ri_id->qp, attr,
@ -291,9 +308,6 @@ rpcrdma_conn_upcall(struct rdma_cm_id *id, struct rdma_cm_event *event)
goto connected;
case RDMA_CM_EVENT_DISCONNECTED:
connstate = -ECONNABORTED;
goto connected;
case RDMA_CM_EVENT_DEVICE_REMOVAL:
connstate = -ENODEV;
connected:
dprintk("RPC: %s: %sconnected\n",
__func__, connstate > 0 ? "" : "dis");
@ -346,6 +360,7 @@ rpcrdma_create_id(struct rpcrdma_xprt *xprt,
int rc;
init_completion(&ia->ri_done);
init_completion(&ia->ri_remove_done);
id = rdma_create_id(&init_net, rpcrdma_conn_upcall, xprt, RDMA_PS_TCP,
IB_QPT_RC);
@ -468,6 +483,56 @@ out_err:
return rc;
}
/**
* rpcrdma_ia_remove - Handle device driver unload
* @ia: interface adapter being removed
*
* Divest transport H/W resources associated with this adapter,
* but allow it to be restored later.
*/
void
rpcrdma_ia_remove(struct rpcrdma_ia *ia)
{
struct rpcrdma_xprt *r_xprt = container_of(ia, struct rpcrdma_xprt,
rx_ia);
struct rpcrdma_ep *ep = &r_xprt->rx_ep;
struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
struct rpcrdma_req *req;
struct rpcrdma_rep *rep;
cancel_delayed_work_sync(&buf->rb_refresh_worker);
/* This is similar to rpcrdma_ep_destroy, but:
* - Don't cancel the connect worker.
* - Don't call rpcrdma_ep_disconnect, which waits
* for another conn upcall, which will deadlock.
* - rdma_disconnect is unneeded, the underlying
* connection is already gone.
*/
if (ia->ri_id->qp) {
ib_drain_qp(ia->ri_id->qp);
rdma_destroy_qp(ia->ri_id);
ia->ri_id->qp = NULL;
}
ib_free_cq(ep->rep_attr.recv_cq);
ib_free_cq(ep->rep_attr.send_cq);
/* The ULP is responsible for ensuring all DMA
* mappings and MRs are gone.
*/
list_for_each_entry(rep, &buf->rb_recv_bufs, rr_list)
rpcrdma_dma_unmap_regbuf(rep->rr_rdmabuf);
list_for_each_entry(req, &buf->rb_allreqs, rl_all) {
rpcrdma_dma_unmap_regbuf(req->rl_rdmabuf);
rpcrdma_dma_unmap_regbuf(req->rl_sendbuf);
rpcrdma_dma_unmap_regbuf(req->rl_recvbuf);
}
rpcrdma_destroy_mrs(buf);
/* Allow waiters to continue */
complete(&ia->ri_remove_done);
}
/**
* rpcrdma_ia_close - Clean up/close an IA.
* @ia: interface adapter to close
@ -1080,7 +1145,8 @@ rpcrdma_get_mw(struct rpcrdma_xprt *r_xprt)
out_nomws:
dprintk("RPC: %s: no MWs available\n", __func__);
schedule_delayed_work(&buf->rb_refresh_worker, 0);
if (r_xprt->rx_ep.rep_connected != -ENODEV)
schedule_delayed_work(&buf->rb_refresh_worker, 0);
/* Allow the reply handler and refresh worker to run */
cond_resched();

7
net/sunrpc/xprtrdma/xprt_rdma.h
View File

@ -69,6 +69,7 @@ struct rpcrdma_ia {
struct rdma_cm_id *ri_id;
struct ib_pd *ri_pd;
struct completion ri_done;
struct completion ri_remove_done;
int ri_async_rc;
unsigned int ri_max_segs;
unsigned int ri_max_frmr_depth;
@ -78,10 +79,15 @@ struct rpcrdma_ia {
bool ri_reminv_expected;
bool ri_implicit_roundup;
enum ib_mr_type ri_mrtype;
unsigned long ri_flags;
struct ib_qp_attr ri_qp_attr;
struct ib_qp_init_attr ri_qp_init_attr;
};
enum {
RPCRDMA_IAF_REMOVING = 0,
};
/*
* RDMA Endpoint -- one per transport instance
*/
@ -511,6 +517,7 @@ extern unsigned int xprt_rdma_memreg_strategy;
* Interface Adapter calls - xprtrdma/verbs.c
*/
int rpcrdma_ia_open(struct rpcrdma_xprt *xprt, struct sockaddr *addr);
void rpcrdma_ia_remove(struct rpcrdma_ia *ia);
void rpcrdma_ia_close(struct rpcrdma_ia *);
bool frwr_is_supported(struct rpcrdma_ia *);
bool fmr_is_supported(struct rpcrdma_ia *);