[PATCH v1 12/18] xprtrdma: Reset MRs in frwr_op_unmap_sync()

Chuck Lever
2016-04-11T20:11:48Z

frwr_op_unmap_sync() is now invoked in a workqueue context, the same
as __frwr_queue_recovery(). There's no need to defer MR reset if
posting LOCAL_INV MRs fails.

This means that even when ib_post_send() fails (which should occur
very rarely) the invalidation and DMA unmapping steps are still done
in the correct order.

Signed-off-by: Chuck Lever <chuck.lever-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
---
net/sunrpc/xprtrdma/frwr_ops.c | 98 ++++++++++++++++++++++++----------------
1 file changed, 60 insertions(+), 38 deletions(-)

diff --git a/net/sunrpc/xprtrdma/frwr_ops.c b/net/sunrpc/xprtrdma/frwr_ops.c
index e1e6ac1..ce245dc 100644
--- a/net/sunrpc/xprtrdma/frwr_ops.c
+++ b/net/sunrpc/xprtrdma/frwr_ops.c
@@ -98,6 +98,32 @@ frwr_destroy_recovery_wq(void)
destroy_workqueue(wq);
}

+static int
+__frwr_reset_mr(struct rpcrdma_ia *ia, struct rpcrdma_mw *r)
+{
+ struct rpcrdma_frmr *f = &r->frmr;
+ int rc;
+
+ rc = ib_dereg_mr(f->fr_mr);
+ if (rc) {
+ pr_warn("rpcrdma: ib_dereg_mr status %d, frwr %p orphaned\n",
+ rc, r);
+ return rc;
+ }
+
+ f->fr_mr = ib_alloc_mr(ia->ri_pd, IB_MR_TYPE_MEM_REG,
+ ia->ri_max_frmr_depth);
+ if (IS_ERR(f->fr_mr)) {
+ pr_warn("rpcrdma: ib_alloc_mr status %ld, frwr %p orphaned\n",
+ PTR_ERR(f->fr_mr), r);
+ return PTR_ERR(f->fr_mr);
+ }
+
+ dprintk("RPC: %s: recovered FRMR %p\n", __func__, r);
+ f->fr_state = FRMR_IS_INVALID;
+ return 0;
+}
+
/* Deferred reset of a single FRMR. Generate a fresh rkey by
* replacing the MR.
*
@@ -111,24 +137,15 @@ __frwr_recovery_worker(struct work_struct *work)
struct rpcrdma_mw *r = container_of(work, struct rpcrdma_mw,
frmr.fr_work);
struct rpcrdma_xprt *r_xprt = 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->frmr.fr_mr))
- goto out_fail;
+ struct rpcrdma_ia *ia = &r_xprt->rx_ia;
+ int rc;

- r->frmr.fr_mr = ib_alloc_mr(pd, IB_MR_TYPE_MEM_REG, depth);
- if (IS_ERR(r->frmr.fr_mr))
- goto out_fail;
+ rc = __frwr_reset_mr(ia, r);
+ if (rc)
+ return;

- dprintk("RPC: %s: recovered FRMR %p\n", __func__, 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.
@@ -490,24 +507,6 @@ __frwr_prepare_linv_wr(struct rpcrdma_mr_seg *seg)
return invalidate_wr;
}

-static void
-__frwr_dma_unmap(struct rpcrdma_xprt *r_xprt, struct rpcrdma_mr_seg *seg,
- int rc)
-{
- struct ib_device *device = r_xprt->rx_ia.ri_device;
- struct rpcrdma_mw *mw = seg->rl_mw;
- struct rpcrdma_frmr *f = &mw->frmr;
-
- seg->rl_mw = NULL;
-
- ib_dma_unmap_sg(device, f->fr_sg, f->fr_nents, f->fr_dir);
-
- if (!rc)
- rpcrdma_put_mw(r_xprt, mw);
- else
- __frwr_queue_recovery(mw);
-}
-
/* Invalidate all memory regions that were registered for "req".
*
* Sleeps until it is safe for the host CPU to access the
@@ -521,6 +520,7 @@ frwr_op_unmap_sync(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req)
struct rpcrdma_mr_seg *seg;
unsigned int i, nchunks;
struct rpcrdma_frmr *f;
+ struct rpcrdma_mw *mw;
int rc;

dprintk("RPC: %s: req %p\n", __func__, req);
@@ -561,11 +561,8 @@ frwr_op_unmap_sync(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req)
* unless ri_id->qp is a valid pointer.
*/
rc = ib_post_send(ia->ri_id->qp, invalidate_wrs, &bad_wr);
- if (rc) {
- pr_warn("%s: ib_post_send failed %i\n", __func__, rc);
- rdma_disconnect(ia->ri_id);
- goto unmap;
- }
+ if (rc)
+ goto reset_mrs;

wait_for_completion(&f->fr_linv_done);

@@ -575,14 +572,39 @@ frwr_op_unmap_sync(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req)
unmap:
for (i = 0, nchunks = req->rl_nchunks; nchunks; nchunks--) {
seg = &req->rl_segments[i];
+ mw = seg->rl_mw;
+ seg->rl_mw = NULL;

- __frwr_dma_unmap(r_xprt, seg, rc);
+ ib_dma_unmap_sg(ia->ri_device, f->fr_sg, f->fr_nents,
+ f->fr_dir);
+ rpcrdma_put_mw(r_xprt, mw);

i += seg->mr_nsegs;
seg->mr_nsegs = 0;
}

req->rl_nchunks = 0;
+ return;
+
+reset_mrs:
+ pr_warn("%s: ib_post_send failed %i\n", __func__, rc);
+
+ /* Find and reset the MRs in the LOCAL_INV WRs that did not
+ * get posted. This is synchronous, and slow.
+ */
+ for (i = 0, nchunks = req->rl_nchunks; nchunks; nchunks--) {
+ seg = &req->rl_segments[i];
+ mw = seg->rl_mw;
+ f = &mw->frmr;
+
+ if (mw->frmr.fr_mr->rkey == bad_wr->ex.invalidate_rkey) {
+ __frwr_reset_mr(ia, mw);
+ bad_wr = bad_wr->next;
+ }
+
+ i += seg->mr_nsegs;
+ }
+ goto unmap;
}

/* Post a LOCAL_INV Work Request to prevent further remote access

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