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authorJ. Bruce Fields <bfields@redhat.com>2014-06-02 12:05:47 -0400
committerJ. Bruce Fields <bfields@redhat.com>2014-06-06 19:22:46 -0400
commit05638dc73af2586517468b1159d4b76e90607359 (patch)
treea3d8f7009fd818bb0bd263d74697cf9d2f1b5e6a
parent3fb87d13ce29637e0ae005fa66a4f917cce6fede (diff)
nfsd4: simplify server xdr->next_page use
The rpc code makes available to the NFS server an array of pages to encod into. The server represents its reply as an xdr buf, with the head pointing into the first page in that array, the pages ** array starting just after that, and the tail (if any) sharing any leftover space in the page used by the head. While encoding, we use xdr_stream->page_ptr to keep track of which page we're currently using. Currently we set xdr_stream->page_ptr to buf->pages, which makes the head a weird exception to the rule that page_ptr always points to the page we're currently encoding into. So, instead set it to buf->pages - 1 (the page actually containing the head), and remove the need for a little unintuitive logic in xdr_get_next_encode_buffer() and xdr_truncate_encode. Signed-off-by: J. Bruce Fields <bfields@redhat.com>
-rw-r--r--fs/nfsd/nfs4proc.c2
-rw-r--r--net/sunrpc/xdr.c9
2 files changed, 6 insertions, 5 deletions
diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index f053c5a9ebf1..6851b003f2a4 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1264,7 +1264,7 @@ static void svcxdr_init_encode(struct svc_rqst *rqstp,
/* Tail and page_len should be zero at this point: */
buf->len = buf->head[0].iov_len;
xdr->scratch.iov_len = 0;
- xdr->page_ptr = buf->pages;
+ xdr->page_ptr = buf->pages - 1;
buf->buflen = PAGE_SIZE * (1 + rqstp->rq_page_end - buf->pages)
- rqstp->rq_auth_slack;
}
diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
index 39928444c7fb..23fb4e75e245 100644
--- a/net/sunrpc/xdr.c
+++ b/net/sunrpc/xdr.c
@@ -523,10 +523,9 @@ __be32 *xdr_get_next_encode_buffer(struct xdr_stream *xdr, size_t nbytes)
frag2bytes = nbytes - frag1bytes;
if (xdr->iov)
xdr->iov->iov_len += frag1bytes;
- else {
+ else
xdr->buf->page_len += frag1bytes;
- xdr->page_ptr++;
- }
+ xdr->page_ptr++;
xdr->iov = NULL;
/*
* If the last encode didn't end exactly on a page boundary, the
@@ -638,8 +637,10 @@ void xdr_truncate_encode(struct xdr_stream *xdr, size_t len)
/* xdr->iov should already be NULL */
return;
}
- if (fraglen)
+ if (fraglen) {
xdr->end = head->iov_base + head->iov_len;
+ xdr->page_ptr--;
+ }
/* (otherwise assume xdr->end is already set) */
head->iov_len = len;
buf->len = len;