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authorTrond Myklebust <trond.myklebust@hammerspace.com>2020-11-21 22:50:43 +0300
committerTrond Myklebust <trond.myklebust@hammerspace.com>2020-12-02 22:05:53 +0300
commit8d86e373b0ef52d091ced9583ffbb33ad2771576 (patch)
treea73b499bafee1d7d38c88f0389e57e490b020640 /net/sunrpc/xdr.c
parent2b1f83d108bd35d12d8a833298d2a033f9121aac (diff)
downloadlinux-8d86e373b0ef52d091ced9583ffbb33ad2771576.tar.xz
SUNRPC: Clean up helpers xdr_set_iov() and xdr_set_page_base()
Allow xdr_set_iov() to set a base so that we can use it to set the cursor to a specific position in the kvec buffer. If the new base overflows the kvec/pages buffer in either xdr_set_iov() or xdr_set_page_base(), then truncate it so that we point to the end of the buffer. Finally, change both function to return the number of bytes remaining to read in their buffers. Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Diffstat (limited to 'net/sunrpc/xdr.c')
-rw-r--r--net/sunrpc/xdr.c36
1 files changed, 19 insertions, 17 deletions
diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
index bc7a622016ee..394297ec1cb9 100644
--- a/net/sunrpc/xdr.c
+++ b/net/sunrpc/xdr.c
@@ -970,19 +970,22 @@ void xdr_write_pages(struct xdr_stream *xdr, struct page **pages, unsigned int b
}
EXPORT_SYMBOL_GPL(xdr_write_pages);
-static void xdr_set_iov(struct xdr_stream *xdr, struct kvec *iov,
- unsigned int len)
+static unsigned int xdr_set_iov(struct xdr_stream *xdr, struct kvec *iov,
+ unsigned int base, unsigned int len)
{
if (len > iov->iov_len)
len = iov->iov_len;
- xdr->p = (__be32*)iov->iov_base;
+ if (unlikely(base > len))
+ base = len;
+ xdr->p = (__be32*)(iov->iov_base + base);
xdr->end = (__be32*)(iov->iov_base + len);
xdr->iov = iov;
xdr->page_ptr = NULL;
+ return len - base;
}
-static int xdr_set_page_base(struct xdr_stream *xdr,
- unsigned int base, unsigned int len)
+static unsigned int xdr_set_page_base(struct xdr_stream *xdr,
+ unsigned int base, unsigned int len)
{
unsigned int pgnr;
unsigned int maxlen;
@@ -991,9 +994,11 @@ static int xdr_set_page_base(struct xdr_stream *xdr,
void *kaddr;
maxlen = xdr->buf->page_len;
- if (base >= maxlen)
- return -EINVAL;
- maxlen -= base;
+ if (base >= maxlen) {
+ base = maxlen;
+ maxlen = 0;
+ } else
+ maxlen -= base;
if (len > maxlen)
len = maxlen;
@@ -1011,14 +1016,14 @@ static int xdr_set_page_base(struct xdr_stream *xdr,
pgend = PAGE_SIZE;
xdr->end = (__be32*)(kaddr + pgend);
xdr->iov = NULL;
- return 0;
+ return len;
}
static void xdr_set_page(struct xdr_stream *xdr, unsigned int base,
unsigned int len)
{
- if (xdr_set_page_base(xdr, base, len) < 0)
- xdr_set_iov(xdr, xdr->buf->tail, xdr->nwords << 2);
+ if (xdr_set_page_base(xdr, base, len) == 0)
+ xdr_set_iov(xdr, xdr->buf->tail, 0, xdr_stream_remaining(xdr));
}
static void xdr_set_next_page(struct xdr_stream *xdr)
@@ -1055,12 +1060,9 @@ void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p,
xdr->scratch.iov_base = NULL;
xdr->scratch.iov_len = 0;
xdr->nwords = XDR_QUADLEN(buf->len);
- if (buf->head[0].iov_len != 0)
- xdr_set_iov(xdr, buf->head, buf->len);
- else if (buf->page_len != 0)
- xdr_set_page_base(xdr, 0, buf->len);
- else
- xdr_set_iov(xdr, buf->tail, buf->len);
+ if (xdr_set_iov(xdr, buf->head, 0, buf->len) == 0 &&
+ xdr_set_page_base(xdr, 0, buf->len) == 0)
+ xdr_set_iov(xdr, buf->tail, 0, buf->len);
if (p != NULL && p > xdr->p && xdr->end >= p) {
xdr->nwords -= p - xdr->p;
xdr->p = p;