[PATCH v1 08/13] xprtrdma: Back off rkey when FAST_REG_MR fails

Chuck Lever
2014-06-23T22:40:07Z

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 <swise-7bPotxP6k4+P2YhJcF5u+vpXobYPEAuW@public.gmane.org>
Signed-off-by: Chuck Lever <chuck.lever-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
---
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);
+ }
}

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;