[PATCH v2 09/10] svcrdma: Move read list XDR round-up logic

Chuck Lever
2015-01-13T16:03:45Z

This is a pre-requisite for a subsequent patch.

Read list XDR round-up needs to be done _before_ additional inline
content is copied to the end of the XDR buffer's page list. Move
the logic added by commit e560e3b510d2 ("svcrdma: Add zero padding
if the client doesn't send it").

Signed-off-by: Chuck Lever <chuck.lever-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
---

net/sunrpc/xprtrdma/svc_rdma_recvfrom.c | 37 ++++++++-----------------------
1 files changed, 9 insertions(+), 28 deletions(-)

diff --git a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
index 36cf51a..a345cad 100644
--- a/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
+++ b/net/sunrpc/xprtrdma/svc_rdma_recvfrom.c
@@ -43,7 +43,6 @@
#include <linux/sunrpc/debug.h>
#include <linux/sunrpc/rpc_rdma.h>
#include <linux/spinlock.h>
-#include <linux/highmem.h>
#include <asm/unaligned.h>
#include <rdma/ib_verbs.h>
#include <rdma/rdma_cm.h>
@@ -434,6 +433,15 @@ static int rdma_read_chunks(struct svcxprt_rdma *xprt,
}
}

+ /* Read list may need XDR round-up (see RFC 5666, s. 3.7) */
+ if (page_offset & 3) {
+ u32 pad = 4 - (page_offset & 3);
+
+ head->arg.page_len += pad;
+ head->arg.len += pad;
+ head->arg.buflen += pad;
+ }
+
ret = 1;
head->position = position;

@@ -446,32 +454,6 @@ static int rdma_read_chunks(struct svcxprt_rdma *xprt,
return ret;
}

-/*
- * To avoid a separate RDMA READ just for a handful of zero bytes,
- * RFC 5666 section 3.7 allows the client to omit the XDR zero pad
- * in chunk lists.
- */
-static void
-rdma_fix_xdr_pad(struct xdr_buf *buf)
-{
- unsigned int page_len = buf->page_len;
- unsigned int size = (XDR_QUADLEN(page_len) << 2) - page_len;
- unsigned int offset, pg_no;
- char *p;
-
- if (size == 0)
- return;
-
- pg_no = page_len >> PAGE_SHIFT;
- offset = page_len & ~PAGE_MASK;
- p = page_address(buf->pages[pg_no]);
- memset(p + offset, 0, size);
-
- buf->page_len += size;
- buf->buflen += size;
- buf->len += size;
-}
-
static int rdma_read_complete(struct svc_rqst *rqstp,
struct svc_rdma_op_ctxt *head)
{
@@ -499,7 +481,6 @@ static int rdma_read_complete(struct svc_rqst *rqstp,
}

/* Point rq_arg.pages past header */
- rdma_fix_xdr_pad(&head->arg);
rqstp->rq_arg.pages = &rqstp->rq_pages[head->hdr_count];
rqstp->rq_arg.page_len = head->arg.page_len;
rqstp->rq_arg.page_base = head->arg.page_base;

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