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-rw-r--r--net/sunrpc/xprtrdma/frwr_ops.c166
1 files changed, 71 insertions, 95 deletions
diff --git a/net/sunrpc/xprtrdma/frwr_ops.c b/net/sunrpc/xprtrdma/frwr_ops.c
index 0b6dad7580a1..30065a28628c 100644
--- a/net/sunrpc/xprtrdma/frwr_ops.c
+++ b/net/sunrpc/xprtrdma/frwr_ops.c
@@ -7,67 +7,37 @@
/* Lightweight memory registration using Fast Registration Work
* Requests (FRWR).
*
- * FRWR features ordered asynchronous registration and deregistration
- * of arbitrarily sized memory regions. This is the fastest and safest
+ * FRWR features ordered asynchronous registration and invalidation
+ * of arbitrarily-sized memory regions. This is the fastest and safest
* but most complex memory registration mode.
*/
/* Normal operation
*
- * A Memory Region is prepared for RDMA READ or WRITE using a FAST_REG
+ * A Memory Region is prepared for RDMA Read or Write using a FAST_REG
* Work Request (frwr_map). When the RDMA operation is finished, this
* Memory Region is invalidated using a LOCAL_INV Work Request
- * (frwr_unmap_sync).
+ * (frwr_unmap_async and frwr_unmap_sync).
*
- * 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
+ * Typically FAST_REG 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_unmap marks MRs INVALID before the
- * LOCAL_INV WR is posted. If posting succeeds, the MR is placed on
- * rb_mrs immediately so that no work (like managing a linked list
- * under a spinlock) is needed in the completion upcall.
- *
- * But this means that frwr_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
- * four states:
- *
- * INVALID: The MR was not in use before the QP entered ERROR state.
- *
- * VALID: The MR was registered before the QP entered ERROR state.
- *
- * FLUSHED_FR: The MR was being registered when the QP entered ERROR
- * state, and the pending WR was flushed.
- *
- * FLUSHED_LI: The MR was being invalidated when the QP entered ERROR
- * state, and the pending WR was flushed.
- *
- * When frwr_map encounters FLUSHED and VALID MRs, they are recovered
- * with ib_dereg_mr and then are re-initialized. Because MR recovery
- * allocates fresh resources, it is deferred to a workqueue, and the
- * recovered MRs are placed back on the rb_mrs list when recovery is
- * complete. frwr_map allocates another MR for the current RPC while
- * the broken MR is reset.
- *
- * To ensure that frwr_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.
+ * frwr_map and frwr_unmap_* cannot run at the same time the transport
+ * connect worker is running. The connect worker holds the transport
+ * send lock, just as ->send_request does. This prevents frwr_map and
+ * the connect worker from running concurrently. When a connection is
+ * closed, the Receive completion queue is drained before the allowing
+ * the connect worker to get control. This prevents frwr_unmap and the
+ * connect worker from running concurrently.
+ *
+ * When the underlying transport disconnects, MRs that are in flight
+ * are flushed and are likely unusable. Thus all flushed MRs are
+ * destroyed. New MRs are created on demand.
*/
#include <linux/sunrpc/rpc_rdma.h>
@@ -118,15 +88,8 @@ void frwr_release_mr(struct rpcrdma_mr *mr)
kfree(mr);
}
-/* MRs are dynamically allocated, so simply clean up and release the MR.
- * A replacement MR will subsequently be allocated on demand.
- */
-static void
-frwr_mr_recycle_worker(struct work_struct *work)
+static void frwr_mr_recycle(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr *mr)
{
- struct rpcrdma_mr *mr = container_of(work, struct rpcrdma_mr, mr_recycle);
- struct rpcrdma_xprt *r_xprt = mr->mr_xprt;
-
trace_xprtrdma_mr_recycle(mr);
if (mr->mr_dir != DMA_NONE) {
@@ -136,14 +99,40 @@ frwr_mr_recycle_worker(struct work_struct *work)
mr->mr_dir = DMA_NONE;
}
- spin_lock(&r_xprt->rx_buf.rb_mrlock);
+ spin_lock(&r_xprt->rx_buf.rb_lock);
list_del(&mr->mr_all);
r_xprt->rx_stats.mrs_recycled++;
- spin_unlock(&r_xprt->rx_buf.rb_mrlock);
+ spin_unlock(&r_xprt->rx_buf.rb_lock);
frwr_release_mr(mr);
}
+/* MRs are dynamically allocated, so simply clean up and release the MR.
+ * A replacement MR will subsequently be allocated on demand.
+ */
+static void
+frwr_mr_recycle_worker(struct work_struct *work)
+{
+ struct rpcrdma_mr *mr = container_of(work, struct rpcrdma_mr,
+ mr_recycle);
+
+ frwr_mr_recycle(mr->mr_xprt, mr);
+}
+
+/* frwr_recycle - Discard MRs
+ * @req: request to reset
+ *
+ * Used after a reconnect. These MRs could be in flight, we can't
+ * tell. Safe thing to do is release them.
+ */
+void frwr_recycle(struct rpcrdma_req *req)
+{
+ struct rpcrdma_mr *mr;
+
+ while ((mr = rpcrdma_mr_pop(&req->rl_registered)))
+ frwr_mr_recycle(mr->mr_xprt, mr);
+}
+
/* frwr_reset - Place MRs back on the free list
* @req: request to reset
*
@@ -156,12 +145,10 @@ frwr_mr_recycle_worker(struct work_struct *work)
*/
void frwr_reset(struct rpcrdma_req *req)
{
- while (!list_empty(&req->rl_registered)) {
- struct rpcrdma_mr *mr;
+ struct rpcrdma_mr *mr;
- mr = rpcrdma_mr_pop(&req->rl_registered);
- rpcrdma_mr_unmap_and_put(mr);
- }
+ while ((mr = rpcrdma_mr_pop(&req->rl_registered)))
+ rpcrdma_mr_put(mr);
}
/**
@@ -179,11 +166,14 @@ int frwr_init_mr(struct rpcrdma_ia *ia, struct rpcrdma_mr *mr)
struct ib_mr *frmr;
int rc;
+ /* NB: ib_alloc_mr and device drivers typically allocate
+ * memory with GFP_KERNEL.
+ */
frmr = ib_alloc_mr(ia->ri_pd, ia->ri_mrtype, depth);
if (IS_ERR(frmr))
goto out_mr_err;
- sg = kcalloc(depth, sizeof(*sg), GFP_KERNEL);
+ sg = kcalloc(depth, sizeof(*sg), GFP_NOFS);
if (!sg)
goto out_list_err;
@@ -203,8 +193,6 @@ out_mr_err:
return rc;
out_list_err:
- dprintk("RPC: %s: sg allocation failure\n",
- __func__);
ib_dereg_mr(frmr);
return -ENOMEM;
}
@@ -290,8 +278,8 @@ int frwr_open(struct rpcrdma_ia *ia, struct rpcrdma_ep *ep)
ep->rep_attr.cap.max_recv_wr += RPCRDMA_BACKWARD_WRS;
ep->rep_attr.cap.max_recv_wr += 1; /* for ib_drain_rq */
- ia->ri_max_segs = max_t(unsigned int, 1, RPCRDMA_MAX_DATA_SEGS /
- ia->ri_max_frwr_depth);
+ ia->ri_max_segs =
+ DIV_ROUND_UP(RPCRDMA_MAX_DATA_SEGS, ia->ri_max_frwr_depth);
/* Reply chunks require segments for head and tail buffers */
ia->ri_max_segs += 2;
if (ia->ri_max_segs > RPCRDMA_MAX_HDR_SEGS)
@@ -323,31 +311,25 @@ size_t frwr_maxpages(struct rpcrdma_xprt *r_xprt)
* @nsegs: number of segments remaining
* @writing: true when RDMA Write will be used
* @xid: XID of RPC using the registered memory
- * @out: initialized MR
+ * @mr: MR to fill in
*
* Prepare a REG_MR Work Request to register a memory region
* for remote access via RDMA READ or RDMA WRITE.
*
* Returns the next segment or a negative errno pointer.
- * On success, the prepared MR is planted in @out.
+ * On success, @mr is filled in.
*/
struct rpcrdma_mr_seg *frwr_map(struct rpcrdma_xprt *r_xprt,
struct rpcrdma_mr_seg *seg,
int nsegs, bool writing, __be32 xid,
- struct rpcrdma_mr **out)
+ struct rpcrdma_mr *mr)
{
struct rpcrdma_ia *ia = &r_xprt->rx_ia;
- bool holes_ok = ia->ri_mrtype == IB_MR_TYPE_SG_GAPS;
- struct rpcrdma_mr *mr;
- struct ib_mr *ibmr;
struct ib_reg_wr *reg_wr;
+ struct ib_mr *ibmr;
int i, n;
u8 key;
- mr = rpcrdma_mr_get(r_xprt);
- if (!mr)
- goto out_getmr_err;
-
if (nsegs > ia->ri_max_frwr_depth)
nsegs = ia->ri_max_frwr_depth;
for (i = 0; i < nsegs;) {
@@ -362,7 +344,7 @@ struct rpcrdma_mr_seg *frwr_map(struct rpcrdma_xprt *r_xprt,
++seg;
++i;
- if (holes_ok)
+ if (ia->ri_mrtype == IB_MR_TYPE_SG_GAPS)
continue;
if ((i < nsegs && offset_in_page(seg->mr_offset)) ||
offset_in_page((seg-1)->mr_offset + (seg-1)->mr_len))
@@ -397,22 +379,15 @@ struct rpcrdma_mr_seg *frwr_map(struct rpcrdma_xprt *r_xprt,
mr->mr_offset = ibmr->iova;
trace_xprtrdma_mr_map(mr);
- *out = mr;
return seg;
-out_getmr_err:
- xprt_wait_for_buffer_space(&r_xprt->rx_xprt);
- return ERR_PTR(-EAGAIN);
-
out_dmamap_err:
mr->mr_dir = DMA_NONE;
trace_xprtrdma_frwr_sgerr(mr, i);
- rpcrdma_mr_put(mr);
return ERR_PTR(-EIO);
out_mapmr_err:
trace_xprtrdma_frwr_maperr(mr, n);
- rpcrdma_mr_recycle(mr);
return ERR_PTR(-EIO);
}
@@ -485,7 +460,7 @@ void frwr_reminv(struct rpcrdma_rep *rep, struct list_head *mrs)
if (mr->mr_handle == rep->rr_inv_rkey) {
list_del_init(&mr->mr_list);
trace_xprtrdma_mr_remoteinv(mr);
- rpcrdma_mr_unmap_and_put(mr);
+ rpcrdma_mr_put(mr);
break; /* only one invalidated MR per RPC */
}
}
@@ -495,7 +470,7 @@ static void __frwr_release_mr(struct ib_wc *wc, struct rpcrdma_mr *mr)
if (wc->status != IB_WC_SUCCESS)
rpcrdma_mr_recycle(mr);
else
- rpcrdma_mr_unmap_and_put(mr);
+ rpcrdma_mr_put(mr);
}
/**
@@ -532,8 +507,8 @@ static void frwr_wc_localinv_wake(struct ib_cq *cq, struct ib_wc *wc)
/* WARNING: Only wr_cqe and status are reliable at this point */
trace_xprtrdma_wc_li_wake(wc, frwr);
- complete(&frwr->fr_linv_done);
__frwr_release_mr(wc, mr);
+ complete(&frwr->fr_linv_done);
}
/**
@@ -562,8 +537,7 @@ void frwr_unmap_sync(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req)
*/
frwr = NULL;
prev = &first;
- while (!list_empty(&req->rl_registered)) {
- mr = rpcrdma_mr_pop(&req->rl_registered);
+ while ((mr = rpcrdma_mr_pop(&req->rl_registered))) {
trace_xprtrdma_mr_localinv(mr);
r_xprt->rx_stats.local_inv_needed++;
@@ -632,11 +606,15 @@ static void frwr_wc_localinv_done(struct ib_cq *cq, struct ib_wc *wc)
struct rpcrdma_frwr *frwr =
container_of(cqe, struct rpcrdma_frwr, fr_cqe);
struct rpcrdma_mr *mr = container_of(frwr, struct rpcrdma_mr, frwr);
+ struct rpcrdma_rep *rep = mr->mr_req->rl_reply;
/* WARNING: Only wr_cqe and status are reliable at this point */
trace_xprtrdma_wc_li_done(wc, frwr);
- rpcrdma_complete_rqst(frwr->fr_req->rl_reply);
__frwr_release_mr(wc, mr);
+
+ /* Ensure @rep is generated before __frwr_release_mr */
+ smp_rmb();
+ rpcrdma_complete_rqst(rep);
}
/**
@@ -662,15 +640,13 @@ void frwr_unmap_async(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req)
*/
frwr = NULL;
prev = &first;
- while (!list_empty(&req->rl_registered)) {
- mr = rpcrdma_mr_pop(&req->rl_registered);
+ while ((mr = rpcrdma_mr_pop(&req->rl_registered))) {
trace_xprtrdma_mr_localinv(mr);
r_xprt->rx_stats.local_inv_needed++;
frwr = &mr->frwr;
frwr->fr_cqe.done = frwr_wc_localinv;
- frwr->fr_req = req;
last = &frwr->fr_invwr;
last->next = NULL;
last->wr_cqe = &frwr->fr_cqe;
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-11 18:25:15 +0000