xprtrdma: Bound the inline threshold values

Currently the sysctls that allow setting the inline threshold allow
any value to be set.

Small values only make the transport run slower. The default 1KB
setting is as low as is reasonable. And the logic that decides how
to divide a Send buffer between RPC-over-RDMA header and RPC message
assumes (but does not check) that the lower bound is not crazy (say,
57 bytes).

Send and receive buffers share a page with some control information.
Values larger than about 3KB can't be supported, currently.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

diff --git a/include/linux/sunrpc/xprtrdma.h b/include/linux/sunrpc/xprtrdma.h
index 767190b013638f2aa0c5e70a3f338adbc6db10a8..39267dc3486af5417f1f0642d353ec65d1e78aa5 100644 (file)
--- a/include/linux/sunrpc/xprtrdma.h
+++ b/include/linux/sunrpc/xprtrdma.h
@@ -52,7 +52,9 @@
 #define RPCRDMA_DEF_SLOT_TABLE (128U)
 #define RPCRDMA_MAX_SLOT_TABLE (256U)
 
-#define RPCRDMA_DEF_INLINE  (1024)     /* default inline max */
+#define RPCRDMA_MIN_INLINE  (1024)     /* min inline thresh */
+#define RPCRDMA_DEF_INLINE  (1024)     /* default inline thresh */
+#define RPCRDMA_MAX_INLINE  (3068)     /* max inline thresh */
 
 /* Memory registration strategies, by number.
  * This is part of a kernel / user space API. Do not remove. */

diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c
index 9954342924dfa4c87dfb9b2dc050970286c6a2a1..16595ff91994e86448ea6e9ede224278e5a63d03 100644 (file)
--- a/net/sunrpc/xprtrdma/transport.c
+++ b/net/sunrpc/xprtrdma/transport.c
@@ -73,6 +73,8 @@ static unsigned int xprt_rdma_memreg_strategy = RPCRDMA_FRMR;
 
 static unsigned int min_slot_table_size = RPCRDMA_MIN_SLOT_TABLE;
 static unsigned int max_slot_table_size = RPCRDMA_MAX_SLOT_TABLE;
+static unsigned int min_inline_size = RPCRDMA_MIN_INLINE;
+static unsigned int max_inline_size = RPCRDMA_MAX_INLINE;
 static unsigned int zero;
 static unsigned int max_padding = PAGE_SIZE;
 static unsigned int min_memreg = RPCRDMA_BOUNCEBUFFERS;
@@ -96,6 +98,8 @@ static struct ctl_table xr_tunables_table[] = {
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
+               .extra1         = &min_inline_size,
+               .extra2         = &max_inline_size,
        },
        {
                .procname       = "rdma_max_inline_write",
@@ -103,6 +107,8 @@ static struct ctl_table xr_tunables_table[] = {
                .maxlen         = sizeof(unsigned int),
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
+               .extra1         = &min_inline_size,
+               .extra2         = &max_inline_size,
        },
        {
                .procname       = "rdma_inline_write_padding",