On Jun 24, 2014, at 11:47 AM, Anna Schumaker [off-list ref] wrote:

On 06/23/2014 06:40 PM, Chuck Lever wrote:

quoted

If posting a FAST_REG_MR Work Reqeust fails, or the FAST_REG WR
flushes, revert the rkey update to avoid subsequent
IB_WC_MW_BIND_ERR completions.

Suggested-by: Steve Wise <redacted>
Signed-off-by: Chuck Lever <redacted>
---
net/sunrpc/xprtrdma/verbs.c |   39 +++++++++++++++++++++++++++++----------
1 file changed, 29 insertions(+), 10 deletions(-)

diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
index cef67fd..3efc007 100644
--- a/net/sunrpc/xprtrdma/verbs.c
+++ b/net/sunrpc/xprtrdma/verbs.c

@@ -61,6 +61,8 @@

# define RPCDBG_FACILITY	RPCDBG_TRANS
#endif

+static void rpcrdma_decrement_frmr_rkey(struct rpcrdma_mw *);
+
/*
 * internal functions
 */

@@ -154,13 +156,17 @@ rpcrdma_sendcq_process_wc(struct ib_wc *wc)

	if (wrid == 0)
		return;
-	if (wc->status != IB_WC_SUCCESS)
-		return;

	fastreg = test_and_clear_bit(RPCRDMA_BIT_FASTREG, &wrid);
	mw = (struct rpcrdma_mw *)wrid;

-	mw->r.frmr.fr_state = fastreg ? FRMR_IS_VALID : FRMR_IS_INVALID;
+	if (wc->status == IB_WC_SUCCESS) {
+		mw->r.frmr.fr_state = fastreg ?
+				FRMR_IS_VALID : FRMR_IS_INVALID;
+	} else {
+		if (fastreg)
+			rpcrdma_decrement_frmr_rkey(mw);

Isn't this the same as "else if (fastreg)”?

Yep, those are logically equivalent. I left them separate, and
left the extra braces, so it would be cleaner to add more logic in
both arms of “if (wc->status == IB_WC_SUCCESS)” in subsequent
patches.

Using “switch (wc->status)” might be more future-proof.

Anna

quoted

+	}
}

static int

@@ -1480,6 +1486,24 @@ rpcrdma_unmap_one(struct rpcrdma_ia *ia, struct rpcrdma_mr_seg *seg)

				seg->mr_dma, seg->mr_dmalen, seg->mr_dir);
}

+static void
+rpcrdma_increment_frmr_rkey(struct rpcrdma_mw *mw)
+{
+	struct ib_mr *frmr = mw->r.frmr.fr_mr;
+	u8 key = frmr->rkey & 0x000000FF;
+
+	ib_update_fast_reg_key(frmr, ++key);
+}
+
+static void
+rpcrdma_decrement_frmr_rkey(struct rpcrdma_mw *mw)
+{
+	struct ib_mr *frmr = mw->r.frmr.fr_mr;
+	u8 key = frmr->rkey & 0x000000FF;
+
+	ib_update_fast_reg_key(frmr, --key);
+}
+
static int
rpcrdma_register_frmr_external(struct rpcrdma_mr_seg *seg,
			int *nsegs, int writing, struct rpcrdma_ia *ia,

@@ -1487,8 +1511,6 @@ rpcrdma_register_frmr_external(struct rpcrdma_mr_seg *seg,

{
	struct rpcrdma_mr_seg *seg1 = seg;
	struct ib_send_wr invalidate_wr, frmr_wr, *bad_wr, *post_wr;
-
-	u8 key;
	int len, pageoff;
	int i, rc;
	int seg_len;

@@ -1552,14 +1574,10 @@ rpcrdma_register_frmr_external(struct rpcrdma_mr_seg *seg,

		rc = -EIO;
		goto out_err;
	}
-
-	/* Bump the key */
-	key = (u8)(seg1->mr_chunk.rl_mw->r.frmr.fr_mr->rkey & 0x000000FF);
-	ib_update_fast_reg_key(seg1->mr_chunk.rl_mw->r.frmr.fr_mr, ++key);
-
	frmr_wr.wr.fast_reg.access_flags = (writing ?
				IB_ACCESS_REMOTE_WRITE | IB_ACCESS_LOCAL_WRITE :
				IB_ACCESS_REMOTE_READ);
+	rpcrdma_increment_frmr_rkey(seg1->mr_chunk.rl_mw);
	frmr_wr.wr.fast_reg.rkey = seg1->mr_chunk.rl_mw->r.frmr.fr_mr->rkey;
	DECR_CQCOUNT(&r_xprt->rx_ep);

@@ -1568,6 +1586,7 @@ rpcrdma_register_frmr_external(struct rpcrdma_mr_seg *seg,

	if (rc) {
		dprintk("RPC:       %s: failed ib_post_send for register,"
			" status %i\n", __func__, rc);
+		rpcrdma_decrement_frmr_rkey(seg1->mr_chunk.rl_mw);
		goto out_err;
	} else {
		seg1->mr_rkey = seg1->mr_chunk.rl_mw->r.frmr.fr_mr->rkey;

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--
Chuck Lever
chuck[dot]lever[at]oracle[dot]com



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