SUNRPC: introduce xdr_init_decode_pages

Initialize xdr_stream and xdr_buf using an array of page pointers
and length of buffer.

Signed-off-by: Benny Halevy <bhalevy@panasas.com>

5 files changed, 27 insertions, 21 deletions

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 7237672216c8..f673a9e1d95d 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -512,12 +512,7 @@ int nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct nfs_entry *en
                                 struct page **xdr_pages, struct page *page, unsigned int buflen)
 {
         struct xdr_stream stream;
-        struct xdr_buf buf = {
-                .pages = xdr_pages,
-                .page_len = buflen,
-                .buflen = buflen,
-                .len = buflen,
-        };
+        struct xdr_buf buf;
         struct page *scratch;
         struct nfs_cache_array *array;
         unsigned int count = 0;
@@ -527,7 +522,7 @@ int nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct nfs_entry *en
         if (scratch == NULL)
                 return -ENOMEM;
 
-        xdr_init_decode(&stream, &buf, NULL);
+        xdr_init_decode_pages(&stream, &buf, xdr_pages, buflen);
         xdr_set_scratch_buffer(&stream, page_address(scratch), PAGE_SIZE);
 
         do {
diff --git a/fs/nfs/nfs4filelayout.c b/fs/nfs/nfs4filelayout.c
index 501a9b86b318..33bda24e8cd2 100644
--- a/fs/nfs/nfs4filelayout.c
+++ b/fs/nfs/nfs4filelayout.c
@@ -510,12 +510,7 @@ filelayout_decode_layout(struct pnfs_layout_hdr *flo,
                          gfp_t gfp_flags)
 {
         struct xdr_stream stream;
-        struct xdr_buf buf = {
-                .pages =  lgr->layoutp->pages,
-                .page_len =  lgr->layoutp->len,
-                .buflen =  lgr->layoutp->len,
-                .len = lgr->layoutp->len,
-        };
+        struct xdr_buf buf;
         struct page *scratch;
         __be32 *p;
         uint32_t nfl_util;
@@ -527,7 +522,7 @@ filelayout_decode_layout(struct pnfs_layout_hdr *flo,
         if (!scratch)
                 return -ENOMEM;
 
-        xdr_init_decode(&stream, &buf, NULL);
+        xdr_init_decode_pages(&stream, &buf, lgr->layoutp->pages, lgr->layoutp->len);
         xdr_set_scratch_buffer(&stream, page_address(scratch), PAGE_SIZE);
 
         /* 20 = ufl_util (4), first_stripe_index (4), pattern_offset (8),
diff --git a/fs/nfs/nfs4filelayoutdev.c b/fs/nfs/nfs4filelayoutdev.c
index 5914659c8ec5..3b7bf1377264 100644
--- a/fs/nfs/nfs4filelayoutdev.c
+++ b/fs/nfs/nfs4filelayoutdev.c
@@ -308,12 +308,7 @@ decode_device(struct inode *ino, struct pnfs_device *pdev, gfp_t gfp_flags)
         u8 max_stripe_index;
         struct nfs4_file_layout_dsaddr *dsaddr = NULL;
         struct xdr_stream stream;
-        struct xdr_buf buf = {
-                .pages = pdev->pages,
-                .page_len = pdev->pglen,
-                .buflen = pdev->pglen,
-                .len = pdev->pglen,
-        };
+        struct xdr_buf buf;
         struct page *scratch;
 
         /* set up xdr stream */
@@ -321,7 +316,7 @@ decode_device(struct inode *ino, struct pnfs_device *pdev, gfp_t gfp_flags)
         if (!scratch)
                 goto out_err;
 
-        xdr_init_decode(&stream, &buf, NULL);
+        xdr_init_decode_pages(&stream, &buf, pdev->pages, pdev->pglen);
         xdr_set_scratch_buffer(&stream, page_address(scratch), PAGE_SIZE);
 
         /* Get the stripe count (number of stripe index) */
diff --git a/include/linux/sunrpc/xdr.h b/include/linux/sunrpc/xdr.h
index fc84b7a19ca3..a20970ef9e4e 100644
--- a/include/linux/sunrpc/xdr.h
+++ b/include/linux/sunrpc/xdr.h
@@ -216,6 +216,8 @@ extern __be32 *xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes);
 extern void xdr_write_pages(struct xdr_stream *xdr, struct page **pages,
                 unsigned int base, unsigned int len);
 extern void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p);
+extern void xdr_init_decode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
+                struct page **pages, unsigned int len);
 extern void xdr_set_scratch_buffer(struct xdr_stream *xdr, void *buf, size_t buflen);
 extern __be32 *xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes);
 extern void xdr_read_pages(struct xdr_stream *xdr, unsigned int len);
diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
index 679cd674b81d..f008c14ad34c 100644
--- a/net/sunrpc/xdr.c
+++ b/net/sunrpc/xdr.c
@@ -638,6 +638,25 @@ void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p)
 }
 EXPORT_SYMBOL_GPL(xdr_init_decode);
 
+/**
+ * xdr_init_decode - Initialize an xdr_stream for decoding data.
+ * @xdr: pointer to xdr_stream struct
+ * @buf: pointer to XDR buffer from which to decode data
+ * @pages: list of pages to decode into
+ * @len: length in bytes of buffer in pages
+ */
+void xdr_init_decode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
+                           struct page **pages, unsigned int len)
+{
+        memset(buf, 0, sizeof(*buf));
+        buf->pages =  pages;
+        buf->page_len =  len;
+        buf->buflen =  len;
+        buf->len = len;
+        xdr_init_decode(xdr, buf, NULL);
+}
+EXPORT_SYMBOL_GPL(xdr_init_decode_pages);
+
 static __be32 * __xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
 {
         __be32 *p = xdr->p;