SUNRPC: Fix up handling of the XDRBUF_SPARSE_PAGES flag
If the allocator fails before it has reached the target number of pages,
then we need to recheck that we're not seeking past the page buffer.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 0898752..cd85c49 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -330,18 +330,16 @@ xs_alloc_sparse_pages(struct xdr_buf *buf, size_t want, gfp_t gfp)
{
size_t i,n;
- if (!(buf->flags & XDRBUF_SPARSE_PAGES))
+ if (!want || !(buf->flags & XDRBUF_SPARSE_PAGES))
return want;
- if (want > buf->page_len)
- want = buf->page_len;
n = (buf->page_base + want + PAGE_SIZE - 1) >> PAGE_SHIFT;
for (i = 0; i < n; i++) {
if (buf->pages[i])
continue;
buf->bvec[i].bv_page = buf->pages[i] = alloc_page(gfp);
if (!buf->pages[i]) {
- buf->page_len = (i * PAGE_SIZE) - buf->page_base;
- return buf->page_len;
+ i *= PAGE_SIZE;
+ return i > buf->page_base ? i - buf->page_base : 0;
}
}
return want;
@@ -404,10 +402,11 @@ xs_read_xdr_buf(struct socket *sock, struct msghdr *msg, int flags,
seek -= buf->head[0].iov_len;
offset += buf->head[0].iov_len;
}
- if (seek < buf->page_len) {
- want = xs_alloc_sparse_pages(buf,
- min_t(size_t, count - offset, buf->page_len),
- GFP_NOWAIT);
+
+ want = xs_alloc_sparse_pages(buf,
+ min_t(size_t, count - offset, buf->page_len),
+ GFP_NOWAIT);
+ if (seek < want) {
ret = xs_read_bvec(sock, msg, flags, buf->bvec,
xdr_buf_pagecount(buf),
want + buf->page_base,
@@ -421,9 +420,10 @@ xs_read_xdr_buf(struct socket *sock, struct msghdr *msg, int flags,
goto out;
seek = 0;
} else {
- seek -= buf->page_len;
- offset += buf->page_len;
+ seek -= want;
+ offset += want;
}
+
if (seek < buf->tail[0].iov_len) {
want = min_t(size_t, count - offset, buf->tail[0].iov_len);
ret = xs_read_kvec(sock, msg, flags, &buf->tail[0], want, seek);