xprtrdma: Prevent infinite loop in rpcrdma_ep_create()

[ Upstream commit 41f97028969e4c88efa5fcf58bc6125210413a6d ]

If a provider advertizes a zero max_fast_reg_page_list_len, FRWR
depth detection loops forever. Instead of just failing the mount,
try other memory registration modes.

Fixes: 0fc6c4e7bb28 ("xprtrdma: mind the device's max fast . . .")
Reported-by: Devesh Sharma <Devesh.Sharma@Emulex.Com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: Devesh Sharma <Devesh.Sharma@Emulex.Com>
Tested-by: Meghana Cheripady <Meghana.Cheripady@Emulex.Com>
Tested-by: Veeresh U. Kokatnur <veereshuk@chelsio.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
index 670c956b0c16fad11d1b95b0e71e8bb48459b2c4..6e5d5034b0f816273e40d5a5a096118bf2c4151e 100644 (file)
--- a/net/sunrpc/xprtrdma/verbs.c
+++ b/net/sunrpc/xprtrdma/verbs.c
@@ -542,9 +542,10 @@ rpcrdma_ia_open(struct rpcrdma_xprt *xprt, struct sockaddr *addr, int memreg)
 
        if (memreg == RPCRDMA_FRMR) {
                /* Requires both frmr reg and local dma lkey */
-               if ((devattr->device_cap_flags &
+               if (((devattr->device_cap_flags &
                     (IB_DEVICE_MEM_MGT_EXTENSIONS|IB_DEVICE_LOCAL_DMA_LKEY)) !=
-                   (IB_DEVICE_MEM_MGT_EXTENSIONS|IB_DEVICE_LOCAL_DMA_LKEY)) {
+                   (IB_DEVICE_MEM_MGT_EXTENSIONS|IB_DEVICE_LOCAL_DMA_LKEY)) ||
+                     (devattr->max_fast_reg_page_list_len == 0)) {
                        dprintk("RPC:       %s: FRMR registration "
                                "not supported by HCA\n", __func__);
                        memreg = RPCRDMA_MTHCAFMR;