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authorTrond Myklebust <Trond.Myklebust@netapp.com>2012-08-02 13:21:43 -0400
committerTrond Myklebust <Trond.Myklebust@netapp.com>2012-09-28 15:58:42 -0400
commita11a2bf4de5679fa0b63474c7d39bea2dac7d061 (patch)
treed59f027797b629d029596f968ccf65dc7916509f /net/sunrpc/xdr.c
parent13fe4ba1b64c099843c75b4f0633ad30a4526637 (diff)
downloadop-kernel-dev-a11a2bf4de5679fa0b63474c7d39bea2dac7d061.zip
op-kernel-dev-a11a2bf4de5679fa0b63474c7d39bea2dac7d061.tar.gz
SUNRPC: Optimise away unnecessary data moves in xdr_align_pages
We only have to call xdr_shrink_pagelen() if the remaining RPC message does not fit in the page buffer length that we supplied to xdr_align_pages(). Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Diffstat (limited to 'net/sunrpc/xdr.c')
-rw-r--r--net/sunrpc/xdr.c23
1 files changed, 13 insertions, 10 deletions
diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
index fbbd1c4..08f50af 100644
--- a/net/sunrpc/xdr.c
+++ b/net/sunrpc/xdr.c
@@ -730,21 +730,24 @@ static unsigned int xdr_align_pages(struct xdr_stream *xdr, unsigned int len)
if (xdr->nwords == 0)
return 0;
- if (nwords > xdr->nwords) {
- nwords = xdr->nwords;
- len = nwords << 2;
- }
/* Realign pages to current pointer position */
iov = buf->head;
- if (iov->iov_len > cur)
+ if (iov->iov_len > cur) {
xdr_shrink_bufhead(buf, iov->iov_len - cur);
+ xdr->nwords = XDR_QUADLEN(buf->len - cur);
+ }
- /* Truncate page data and move it into the tail */
- if (buf->page_len > len)
- xdr_shrink_pagelen(buf, buf->page_len - len);
- else
+ if (nwords > xdr->nwords) {
+ nwords = xdr->nwords;
+ len = nwords << 2;
+ }
+ if (buf->page_len <= len)
len = buf->page_len;
- xdr->nwords = XDR_QUADLEN(buf->len - cur);
+ else if (nwords < xdr->nwords) {
+ /* Truncate page data and move it into the tail */
+ xdr_shrink_pagelen(buf, buf->page_len - len);
+ xdr->nwords = XDR_QUADLEN(buf->len - cur);
+ }
return len;
}
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