summaryrefslogtreecommitdiff
path: root/net/sunrpc/xprtrdma/frwr_ops.c
diff options
context:
space:
mode:
Diffstat (limited to 'net/sunrpc/xprtrdma/frwr_ops.c')
-rw-r--r--net/sunrpc/xprtrdma/frwr_ops.c229
1 files changed, 168 insertions, 61 deletions
diff --git a/net/sunrpc/xprtrdma/frwr_ops.c b/net/sunrpc/xprtrdma/frwr_ops.c
index dff0481db..04ea91420 100644
--- a/net/sunrpc/xprtrdma/frwr_ops.c
+++ b/net/sunrpc/xprtrdma/frwr_ops.c
@@ -11,12 +11,136 @@
* but most complex memory registration mode.
*/
+/* Normal operation
+ *
+ * A Memory Region is prepared for RDMA READ or WRITE using a FAST_REG
+ * Work Request (frmr_op_map). When the RDMA operation is finished, this
+ * Memory Region is invalidated using a LOCAL_INV Work Request
+ * (frmr_op_unmap).
+ *
+ * Typically these Work Requests are not signaled, and neither are RDMA
+ * SEND Work Requests (with the exception of signaling occasionally to
+ * prevent provider work queue overflows). This greatly reduces HCA
+ * interrupt workload.
+ *
+ * As an optimization, frwr_op_unmap marks MRs INVALID before the
+ * LOCAL_INV WR is posted. If posting succeeds, the MR is placed on
+ * rb_mws immediately so that no work (like managing a linked list
+ * under a spinlock) is needed in the completion upcall.
+ *
+ * But this means that frwr_op_map() can occasionally encounter an MR
+ * that is INVALID but the LOCAL_INV WR has not completed. Work Queue
+ * ordering prevents a subsequent FAST_REG WR from executing against
+ * that MR while it is still being invalidated.
+ */
+
+/* Transport recovery
+ *
+ * ->op_map and the transport connect worker cannot run at the same
+ * time, but ->op_unmap can fire while the transport connect worker
+ * is running. Thus MR recovery is handled in ->op_map, to guarantee
+ * that recovered MRs are owned by a sending RPC, and not one where
+ * ->op_unmap could fire at the same time transport reconnect is
+ * being done.
+ *
+ * When the underlying transport disconnects, MRs are left in one of
+ * three states:
+ *
+ * INVALID: The MR was not in use before the QP entered ERROR state.
+ * (Or, the LOCAL_INV WR has not completed or flushed yet).
+ *
+ * STALE: The MR was being registered or unregistered when the QP
+ * entered ERROR state, and the pending WR was flushed.
+ *
+ * VALID: The MR was registered before the QP entered ERROR state.
+ *
+ * When frwr_op_map encounters STALE and VALID MRs, they are recovered
+ * with ib_dereg_mr and then are re-initialized. Beause MR recovery
+ * allocates fresh resources, it is deferred to a workqueue, and the
+ * recovered MRs are placed back on the rb_mws list when recovery is
+ * complete. frwr_op_map allocates another MR for the current RPC while
+ * the broken MR is reset.
+ *
+ * To ensure that frwr_op_map doesn't encounter an MR that is marked
+ * INVALID but that is about to be flushed due to a previous transport
+ * disconnect, the transport connect worker attempts to drain all
+ * pending send queue WRs before the transport is reconnected.
+ */
+
#include "xprt_rdma.h"
#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
# define RPCDBG_FACILITY RPCDBG_TRANS
#endif
+static struct workqueue_struct *frwr_recovery_wq;
+
+#define FRWR_RECOVERY_WQ_FLAGS (WQ_UNBOUND | WQ_MEM_RECLAIM)
+
+int
+frwr_alloc_recovery_wq(void)
+{
+ frwr_recovery_wq = alloc_workqueue("frwr_recovery",
+ FRWR_RECOVERY_WQ_FLAGS, 0);
+ return !frwr_recovery_wq ? -ENOMEM : 0;
+}
+
+void
+frwr_destroy_recovery_wq(void)
+{
+ struct workqueue_struct *wq;
+
+ if (!frwr_recovery_wq)
+ return;
+
+ wq = frwr_recovery_wq;
+ frwr_recovery_wq = NULL;
+ destroy_workqueue(wq);
+}
+
+/* Deferred reset of a single FRMR. Generate a fresh rkey by
+ * replacing the MR.
+ *
+ * There's no recovery if this fails. The FRMR is abandoned, but
+ * remains in rb_all. It will be cleaned up when the transport is
+ * destroyed.
+ */
+static void
+__frwr_recovery_worker(struct work_struct *work)
+{
+ struct rpcrdma_mw *r = container_of(work, struct rpcrdma_mw,
+ r.frmr.fr_work);
+ struct rpcrdma_xprt *r_xprt = r->r.frmr.fr_xprt;
+ unsigned int depth = r_xprt->rx_ia.ri_max_frmr_depth;
+ struct ib_pd *pd = r_xprt->rx_ia.ri_pd;
+
+ if (ib_dereg_mr(r->r.frmr.fr_mr))
+ goto out_fail;
+
+ r->r.frmr.fr_mr = ib_alloc_fast_reg_mr(pd, depth);
+ if (IS_ERR(r->r.frmr.fr_mr))
+ goto out_fail;
+
+ dprintk("RPC: %s: recovered FRMR %p\n", __func__, r);
+ r->r.frmr.fr_state = FRMR_IS_INVALID;
+ rpcrdma_put_mw(r_xprt, r);
+ return;
+
+out_fail:
+ pr_warn("RPC: %s: FRMR %p unrecovered\n",
+ __func__, r);
+}
+
+/* A broken MR was discovered in a context that can't sleep.
+ * Defer recovery to the recovery worker.
+ */
+static void
+__frwr_queue_recovery(struct rpcrdma_mw *r)
+{
+ INIT_WORK(&r->r.frmr.fr_work, __frwr_recovery_worker);
+ queue_work(frwr_recovery_wq, &r->r.frmr.fr_work);
+}
+
static int
__frwr_init(struct rpcrdma_mw *r, struct ib_pd *pd, struct ib_device *device,
unsigned int depth)
@@ -128,8 +252,8 @@ frwr_sendcompletion(struct ib_wc *wc)
/* WARNING: Only wr_id and status are reliable at this point */
r = (struct rpcrdma_mw *)(unsigned long)wc->wr_id;
- dprintk("RPC: %s: frmr %p (stale), status %d\n",
- __func__, r, wc->status);
+ pr_warn("RPC: %s: frmr %p flushed, status %s (%d)\n",
+ __func__, r, ib_wc_status_msg(wc->status), wc->status);
r->r.frmr.fr_state = FRMR_IS_STALE;
}
@@ -137,16 +261,19 @@ static int
frwr_op_init(struct rpcrdma_xprt *r_xprt)
{
struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
- struct ib_device *device = r_xprt->rx_ia.ri_id->device;
+ struct ib_device *device = r_xprt->rx_ia.ri_device;
unsigned int depth = r_xprt->rx_ia.ri_max_frmr_depth;
struct ib_pd *pd = r_xprt->rx_ia.ri_pd;
int i;
+ spin_lock_init(&buf->rb_mwlock);
INIT_LIST_HEAD(&buf->rb_mws);
INIT_LIST_HEAD(&buf->rb_all);
- i = (buf->rb_max_requests + 1) * RPCRDMA_MAX_SEGS;
- dprintk("RPC: %s: initializing %d FRMRs\n", __func__, i);
+ i = max_t(int, RPCRDMA_MAX_DATA_SEGS / depth, 1);
+ i += 2; /* head + tail */
+ i *= buf->rb_max_requests; /* one set for each RPC slot */
+ dprintk("RPC: %s: initalizing %d FRMRs\n", __func__, i);
while (i--) {
struct rpcrdma_mw *r;
@@ -165,6 +292,7 @@ frwr_op_init(struct rpcrdma_xprt *r_xprt)
list_add(&r->mw_list, &buf->rb_mws);
list_add(&r->mw_all, &buf->rb_all);
r->mw_sendcompletion = frwr_sendcompletion;
+ r->r.frmr.fr_xprt = r_xprt;
}
return 0;
@@ -178,12 +306,12 @@ frwr_op_map(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg,
int nsegs, bool writing)
{
struct rpcrdma_ia *ia = &r_xprt->rx_ia;
- struct ib_device *device = ia->ri_id->device;
+ struct ib_device *device = ia->ri_device;
enum dma_data_direction direction = rpcrdma_data_dir(writing);
struct rpcrdma_mr_seg *seg1 = seg;
- struct rpcrdma_mw *mw = seg1->rl_mw;
- struct rpcrdma_frmr *frmr = &mw->r.frmr;
- struct ib_mr *mr = frmr->fr_mr;
+ struct rpcrdma_mw *mw;
+ struct rpcrdma_frmr *frmr;
+ struct ib_mr *mr;
struct ib_send_wr fastreg_wr, *bad_wr;
u8 key;
int len, pageoff;
@@ -192,12 +320,25 @@ frwr_op_map(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg,
u64 pa;
int page_no;
+ mw = seg1->rl_mw;
+ seg1->rl_mw = NULL;
+ do {
+ if (mw)
+ __frwr_queue_recovery(mw);
+ mw = rpcrdma_get_mw(r_xprt);
+ if (!mw)
+ return -ENOMEM;
+ } while (mw->r.frmr.fr_state != FRMR_IS_INVALID);
+ frmr = &mw->r.frmr;
+ frmr->fr_state = FRMR_IS_VALID;
+
pageoff = offset_in_page(seg1->mr_offset);
seg1->mr_offset -= pageoff; /* start of page */
seg1->mr_len += pageoff;
len = -pageoff;
if (nsegs > ia->ri_max_frmr_depth)
nsegs = ia->ri_max_frmr_depth;
+
for (page_no = i = 0; i < nsegs;) {
rpcrdma_map_one(device, seg, direction);
pa = seg->mr_dma;
@@ -216,8 +357,6 @@ frwr_op_map(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg,
dprintk("RPC: %s: Using frmr %p to map %d segments (%d bytes)\n",
__func__, mw, i, len);
- frmr->fr_state = FRMR_IS_VALID;
-
memset(&fastreg_wr, 0, sizeof(fastreg_wr));
fastreg_wr.wr_id = (unsigned long)(void *)mw;
fastreg_wr.opcode = IB_WR_FAST_REG_MR;
@@ -229,6 +368,7 @@ frwr_op_map(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg,
fastreg_wr.wr.fast_reg.access_flags = writing ?
IB_ACCESS_REMOTE_WRITE | IB_ACCESS_LOCAL_WRITE :
IB_ACCESS_REMOTE_READ;
+ mr = frmr->fr_mr;
key = (u8)(mr->rkey & 0x000000FF);
ib_update_fast_reg_key(mr, ++key);
fastreg_wr.wr.fast_reg.rkey = mr->rkey;
@@ -238,6 +378,7 @@ frwr_op_map(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg,
if (rc)
goto out_senderr;
+ seg1->rl_mw = mw;
seg1->mr_rkey = mr->rkey;
seg1->mr_base = seg1->mr_dma + pageoff;
seg1->mr_nsegs = i;
@@ -246,10 +387,9 @@ frwr_op_map(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg,
out_senderr:
dprintk("RPC: %s: ib_post_send status %i\n", __func__, rc);
- ib_update_fast_reg_key(mr, --key);
- frmr->fr_state = FRMR_IS_INVALID;
while (i--)
rpcrdma_unmap_one(device, --seg);
+ __frwr_queue_recovery(mw);
return rc;
}
@@ -261,78 +401,46 @@ frwr_op_unmap(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg)
{
struct rpcrdma_mr_seg *seg1 = seg;
struct rpcrdma_ia *ia = &r_xprt->rx_ia;
+ struct rpcrdma_mw *mw = seg1->rl_mw;
struct ib_send_wr invalidate_wr, *bad_wr;
int rc, nsegs = seg->mr_nsegs;
- struct ib_device *device;
- seg1->rl_mw->r.frmr.fr_state = FRMR_IS_INVALID;
+ dprintk("RPC: %s: FRMR %p\n", __func__, mw);
+
+ seg1->rl_mw = NULL;
+ mw->r.frmr.fr_state = FRMR_IS_INVALID;
memset(&invalidate_wr, 0, sizeof(invalidate_wr));
- invalidate_wr.wr_id = (unsigned long)(void *)seg1->rl_mw;
+ invalidate_wr.wr_id = (unsigned long)(void *)mw;
invalidate_wr.opcode = IB_WR_LOCAL_INV;
- invalidate_wr.ex.invalidate_rkey = seg1->rl_mw->r.frmr.fr_mr->rkey;
+ invalidate_wr.ex.invalidate_rkey = mw->r.frmr.fr_mr->rkey;
DECR_CQCOUNT(&r_xprt->rx_ep);
- read_lock(&ia->ri_qplock);
- device = ia->ri_id->device;
while (seg1->mr_nsegs--)
- rpcrdma_unmap_one(device, seg++);
+ rpcrdma_unmap_one(ia->ri_device, seg++);
+ read_lock(&ia->ri_qplock);
rc = ib_post_send(ia->ri_id->qp, &invalidate_wr, &bad_wr);
read_unlock(&ia->ri_qplock);
if (rc)
goto out_err;
+
+ rpcrdma_put_mw(r_xprt, mw);
return nsegs;
out_err:
- /* Force rpcrdma_buffer_get() to retry */
- seg1->rl_mw->r.frmr.fr_state = FRMR_IS_STALE;
dprintk("RPC: %s: ib_post_send status %i\n", __func__, rc);
+ __frwr_queue_recovery(mw);
return nsegs;
}
-/* After a disconnect, a flushed FAST_REG_MR can leave an FRMR in
- * an unusable state. Find FRMRs in this state and dereg / reg
- * each. FRMRs that are VALID and attached to an rpcrdma_req are
- * also torn down.
- *
- * This gives all in-use FRMRs a fresh rkey and leaves them INVALID.
- *
- * This is invoked only in the transport connect worker in order
- * to serialize with rpcrdma_register_frmr_external().
- */
-static void
-frwr_op_reset(struct rpcrdma_xprt *r_xprt)
-{
- struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
- struct ib_device *device = r_xprt->rx_ia.ri_id->device;
- unsigned int depth = r_xprt->rx_ia.ri_max_frmr_depth;
- struct ib_pd *pd = r_xprt->rx_ia.ri_pd;
- struct rpcrdma_mw *r;
- int rc;
-
- list_for_each_entry(r, &buf->rb_all, mw_all) {
- if (r->r.frmr.fr_state == FRMR_IS_INVALID)
- continue;
-
- __frwr_release(r);
- rc = __frwr_init(r, pd, device, depth);
- if (rc) {
- dprintk("RPC: %s: mw %p left %s\n",
- __func__, r,
- (r->r.frmr.fr_state == FRMR_IS_STALE ?
- "stale" : "valid"));
- continue;
- }
-
- r->r.frmr.fr_state = FRMR_IS_INVALID;
- }
-}
-
static void
frwr_op_destroy(struct rpcrdma_buffer *buf)
{
struct rpcrdma_mw *r;
+ /* Ensure stale MWs for "buf" are no longer in flight */
+ flush_workqueue(frwr_recovery_wq);
+
while (!list_empty(&buf->rb_all)) {
r = list_entry(buf->rb_all.next, struct rpcrdma_mw, mw_all);
list_del(&r->mw_all);
@@ -347,7 +455,6 @@ const struct rpcrdma_memreg_ops rpcrdma_frwr_memreg_ops = {
.ro_open = frwr_op_open,
.ro_maxpages = frwr_op_maxpages,
.ro_init = frwr_op_init,
- .ro_reset = frwr_op_reset,
.ro_destroy = frwr_op_destroy,
.ro_displayname = "frwr",
};
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-17 14:55:08 +0000