xprtrdma: Fix DMAR failure in frwr_op_map() after reconnect

When a LOCALINV WR is flushed, the frmr is marked STALE, then
frwr_op_unmap_sync DMA-unmaps the frmr's SGL. These STALE frmrs
are then recovered when frwr_op_map hunts for an INVALID frmr to
use.

All other cases that need frmr recovery leave that SGL DMA-mapped.
The FRMR recovery path unconditionally DMA-unmaps the frmr's SGL.

To avoid DMA unmapping the SGL twice for flushed LOCAL_INV WRs,
alter the recovery logic (rather than the hot frwr_op_unmap_sync
path) to distinguish among these cases. This solution also takes
care of the case where multiple LOCAL_INV WRs are issued for the
same rpcrdma_req, some complete successfully, but some are flushed.

Reported-by: Vasco Steinmetz <linux@kyberraum.net>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: Vasco Steinmetz <linux@kyberraum.net>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

diff --git a/net/sunrpc/xprtrdma/frwr_ops.c b/net/sunrpc/xprtrdma/frwr_ops.c
index 210949562786665ea1a2990e2e9e6f886e580af6..26b26beef2d4a6dd7ef9d31f09de7fe51504d841 100644 (file)
--- a/net/sunrpc/xprtrdma/frwr_ops.c
+++ b/net/sunrpc/xprtrdma/frwr_ops.c
@@ -44,18 +44,20 @@
  * being done.
  *
  * When the underlying transport disconnects, MRs are left in one of
- * three states:
+ * four 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
+ * 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_op_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_mws list when recovery is
  * complete. frwr_op_map allocates another MR for the current RPC while
@@ -177,12 +179,15 @@ __frwr_reset_mr(struct rpcrdma_ia *ia, struct rpcrdma_mw *r)
 static void
 frwr_op_recover_mr(struct rpcrdma_mw *mw)
 {
+       enum rpcrdma_frmr_state state = mw->frmr.fr_state;
        struct rpcrdma_xprt *r_xprt = mw->mw_xprt;
        struct rpcrdma_ia *ia = &r_xprt->rx_ia;
        int rc;
 
        rc = __frwr_reset_mr(ia, mw);
-       ib_dma_unmap_sg(ia->ri_device, mw->mw_sg, mw->mw_nents, mw->mw_dir);
+       if (state != FRMR_FLUSHED_LI)
+               ib_dma_unmap_sg(ia->ri_device,
+                               mw->mw_sg, mw->mw_nents, mw->mw_dir);
        if (rc)
                goto out_release;
 
@@ -262,10 +267,8 @@ frwr_op_maxpages(struct rpcrdma_xprt *r_xprt)
 }
 
 static void
-__frwr_sendcompletion_flush(struct ib_wc *wc, struct rpcrdma_frmr *frmr,
-                           const char *wr)
+__frwr_sendcompletion_flush(struct ib_wc *wc, const char *wr)
 {
-       frmr->fr_state = FRMR_IS_STALE;
        if (wc->status != IB_WC_WR_FLUSH_ERR)
                pr_err("rpcrdma: %s: %s (%u/0x%x)\n",
                       wr, ib_wc_status_msg(wc->status),
@@ -288,7 +291,8 @@ frwr_wc_fastreg(struct ib_cq *cq, struct ib_wc *wc)
        if (wc->status != IB_WC_SUCCESS) {
                cqe = wc->wr_cqe;
                frmr = container_of(cqe, struct rpcrdma_frmr, fr_cqe);
-               __frwr_sendcompletion_flush(wc, frmr, "fastreg");
+               frmr->fr_state = FRMR_FLUSHED_FR;
+               __frwr_sendcompletion_flush(wc, "fastreg");
        }
 }
 
@@ -308,7 +312,8 @@ frwr_wc_localinv(struct ib_cq *cq, struct ib_wc *wc)
        if (wc->status != IB_WC_SUCCESS) {
                cqe = wc->wr_cqe;
                frmr = container_of(cqe, struct rpcrdma_frmr, fr_cqe);
-               __frwr_sendcompletion_flush(wc, frmr, "localinv");
+               frmr->fr_state = FRMR_FLUSHED_LI;
+               __frwr_sendcompletion_flush(wc, "localinv");
        }
 }
 
@@ -328,8 +333,10 @@ frwr_wc_localinv_wake(struct ib_cq *cq, struct ib_wc *wc)
        /* WARNING: Only wr_cqe and status are reliable at this point */
        cqe = wc->wr_cqe;
        frmr = container_of(cqe, struct rpcrdma_frmr, fr_cqe);
-       if (wc->status != IB_WC_SUCCESS)
-               __frwr_sendcompletion_flush(wc, frmr, "localinv");
+       if (wc->status != IB_WC_SUCCESS) {
+               frmr->fr_state = FRMR_FLUSHED_LI;
+               __frwr_sendcompletion_flush(wc, "localinv");
+       }
        complete(&frmr->fr_linv_done);
 }
 

diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h
index 0d35b761c883d01a044ba5f9c635bb3a7edce741..6e1bba358203694e79cbc9074554b12053fa45c7 100644 (file)
--- a/net/sunrpc/xprtrdma/xprt_rdma.h
+++ b/net/sunrpc/xprtrdma/xprt_rdma.h
@@ -216,7 +216,8 @@ struct rpcrdma_rep {
 enum rpcrdma_frmr_state {
        FRMR_IS_INVALID,        /* ready to be used */
        FRMR_IS_VALID,          /* in use */
-       FRMR_IS_STALE,          /* failed completion */
+       FRMR_FLUSHED_FR,        /* flushed FASTREG WR */
+       FRMR_FLUSHED_LI,        /* flushed LOCALINV WR */
 };
 
 struct rpcrdma_frmr {