SUNRPC: Add helpers for decoding list discriminators symbolically

Use these helpers in a few spots to demonstrate their use.

The remaining open-coded discriminator checks in rpcrdma will be
addressed in subsequent patches.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

diff --git a/include/linux/sunrpc/xdr.h b/include/linux/sunrpc/xdr.h
index 22c207b2425fc2b4ef915b0dc591e094257c5970..5a6a81b7cd9f7fde40d3b5e0eda242dd332ac981 100644 (file)
--- a/include/linux/sunrpc/xdr.h
+++ b/include/linux/sunrpc/xdr.h
@@ -474,6 +474,32 @@ xdr_stream_encode_uint32_array(struct xdr_stream *xdr,
        return ret;
 }
 
+/**
+ * xdr_item_is_absent - symbolically handle XDR discriminators
+ * @p: pointer to undecoded discriminator
+ *
+ * Return values:
+ *   %true if the following XDR item is absent
+ *   %false if the following XDR item is present
+ */
+static inline bool xdr_item_is_absent(const __be32 *p)
+{
+       return *p == xdr_zero;
+}
+
+/**
+ * xdr_item_is_present - symbolically handle XDR discriminators
+ * @p: pointer to undecoded discriminator
+ *
+ * Return values:
+ *   %true if the following XDR item is present
+ *   %false if the following XDR item is absent
+ */
+static inline bool xdr_item_is_present(const __be32 *p)
+{
+       return *p != xdr_zero;
+}
+
 /**
  * xdr_stream_decode_u32 - Decode a 32-bit integer
  * @xdr: pointer to xdr_stream

diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c
index 935bbef2f7bef1388f33697e05d465296131511e..feecd1f55f180b1b5747440de850ab758fa48bc7 100644 (file)
--- a/net/sunrpc/xprtrdma/rpc_rdma.c
+++ b/net/sunrpc/xprtrdma/rpc_rdma.c
@@ -1133,11 +1133,11 @@ rpcrdma_is_bcall(struct rpcrdma_xprt *r_xprt, struct rpcrdma_rep *rep)
        p = xdr_inline_decode(xdr, 0);
 
        /* Chunk lists */
-       if (*p++ != xdr_zero)
+       if (xdr_item_is_present(p++))
                return false;
-       if (*p++ != xdr_zero)
+       if (xdr_item_is_present(p++))
                return false;
-       if (*p++ != xdr_zero)
+       if (xdr_item_is_present(p++))
                return false;
 
        /* RPC header */
@@ -1215,7 +1215,7 @@ static int decode_read_list(struct xdr_stream *xdr)
        p = xdr_inline_decode(xdr, sizeof(*p));
        if (unlikely(!p))
                return -EIO;
-       if (unlikely(*p != xdr_zero))
+       if (unlikely(xdr_item_is_present(p)))
                return -EIO;
        return 0;
 }
@@ -1234,7 +1234,7 @@ static int decode_write_list(struct xdr_stream *xdr, u32 *length)
                p = xdr_inline_decode(xdr, sizeof(*p));
                if (unlikely(!p))
                        return -EIO;
-               if (*p == xdr_zero)
+               if (xdr_item_is_absent(p))
                        break;
                if (!first)
                        return -EIO;
@@ -1256,7 +1256,7 @@ static int decode_reply_chunk(struct xdr_stream *xdr, u32 *length)
                return -EIO;
 
        *length = 0;
-       if (*p != xdr_zero)
+       if (xdr_item_is_present(p))
                if (decode_write_chunk(xdr, length))
                        return -EIO;
        return 0;

diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
index c072ce61b3938edc77936939070a8f46fa738858..5e78067889f349b71b41bf43f052fdaa2ed5f88b 100644 (file)
--- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
@@ -419,7 +419,7 @@ static bool xdr_check_read_list(struct svc_rdma_recv_ctxt *rctxt)
 
        len = 0;
        first = true;
-       while (*p != xdr_zero) {
+       while (xdr_item_is_present(p)) {
                p = xdr_inline_decode(&rctxt->rc_stream,
                                      rpcrdma_readseg_maxsz * sizeof(*p));
                if (!p)
@@ -500,7 +500,7 @@ static bool xdr_check_write_list(struct svc_rdma_recv_ctxt *rctxt)
        if (!p)
                return false;
        rctxt->rc_write_list = p;
-       while (*p != xdr_zero) {
+       while (xdr_item_is_present(p)) {
                if (!xdr_check_write_chunk(rctxt, MAX_BYTES_WRITE_CHUNK))
                        return false;
                ++chcount;
@@ -532,12 +532,11 @@ static bool xdr_check_reply_chunk(struct svc_rdma_recv_ctxt *rctxt)
        p = xdr_inline_decode(&rctxt->rc_stream, sizeof(*p));
        if (!p)
                return false;
-       rctxt->rc_reply_chunk = p;
-       if (*p != xdr_zero) {
+       rctxt->rc_reply_chunk = NULL;
+       if (xdr_item_is_present(p)) {
                if (!xdr_check_write_chunk(rctxt, MAX_BYTES_SPECIAL_CHUNK))
                        return false;
-       } else {
-               rctxt->rc_reply_chunk = NULL;
+               rctxt->rc_reply_chunk = p;
        }
        return true;
 }
@@ -568,7 +567,7 @@ static void svc_rdma_get_inv_rkey(struct svcxprt_rdma *rdma,
        p += rpcrdma_fixed_maxsz;
 
        /* Read list */
-       while (*p++ != xdr_zero) {
+       while (xdr_item_is_present(p++)) {
                p++;    /* position */
                if (inv_rkey == xdr_zero)
                        inv_rkey = *p;
@@ -578,7 +577,7 @@ static void svc_rdma_get_inv_rkey(struct svcxprt_rdma *rdma,
        }
 
        /* Write list */
-       while (*p++ != xdr_zero) {
+       while (xdr_item_is_present(p++)) {
                segcount = be32_to_cpup(p++);
                for (i = 0; i < segcount; i++) {
                        if (inv_rkey == xdr_zero)
@@ -590,7 +589,7 @@ static void svc_rdma_get_inv_rkey(struct svcxprt_rdma *rdma,
        }
 
        /* Reply chunk */
-       if (*p++ != xdr_zero) {
+       if (xdr_item_is_present(p++)) {
                segcount = be32_to_cpup(p++);
                for (i = 0; i < segcount; i++) {
                        if (inv_rkey == xdr_zero)