From 8d86e373b0ef52d091ced9583ffbb33ad2771576 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Sat, 21 Nov 2020 14:50:43 -0500 Subject: 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 --- net/sunrpc/xdr.c | 36 +++++++++++++++++++----------------- 1 file changed, 19 insertions(+), 17 deletions(-) (limited to 'net/sunrpc/xdr.c') 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; -- cgit v1.2.3