From 6707fbd7d3be72da4ebde7f56b46814befd2db19 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Sun, 6 Dec 2020 10:15:04 -0500 Subject: [PATCH] SUNRPC: Cleanup xdr_shrink_bufhead() Clean up xdr_shrink_bufhead() to use the new helpers instead of doing its own thing. Signed-off-by: Trond Myklebust --- net/sunrpc/xdr.c | 164 +++++++++++++++++++++++++---------------------- 1 file changed, 87 insertions(+), 77 deletions(-) diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c index e0906ed24374..19eaa38f7d16 100644 --- a/net/sunrpc/xdr.c +++ b/net/sunrpc/xdr.c @@ -550,6 +550,53 @@ static void xdr_buf_pages_copy_right(const struct xdr_buf *buf, buf->page_base + base, pglen); } +static void xdr_buf_head_copy_right(const struct xdr_buf *buf, + unsigned int base, unsigned int len, + unsigned int shift) +{ + const struct kvec *head = buf->head; + const struct kvec *tail = buf->tail; + unsigned int to = base + shift; + unsigned int pglen = 0, pgto = 0; + unsigned int talen = 0, tato = 0; + + if (base >= head->iov_len) + return; + if (len > head->iov_len - base) + len = head->iov_len - base; + if (to >= buf->page_len + head->iov_len) { + tato = to - buf->page_len - head->iov_len; + talen = len; + } else if (to >= head->iov_len) { + pgto = to - head->iov_len; + pglen = len; + if (pgto + pglen > buf->page_len) { + talen = pgto + pglen - buf->page_len; + pglen -= talen; + } + } else { + pglen = len - to; + if (pglen > buf->page_len) { + talen = pglen - buf->page_len; + pglen = buf->page_len; + } + } + + len -= talen; + base += len; + if (talen + tato > tail->iov_len) + talen = tail->iov_len > tato ? tail->iov_len - tato : 0; + memcpy(tail->iov_base + tato, head->iov_base + base, talen); + + len -= pglen; + base -= pglen; + _copy_to_pages(buf->pages, buf->page_base + pgto, head->iov_base + base, + pglen); + + base -= len; + memmove(head->iov_base + to, head->iov_base + base, len); +} + static void xdr_buf_tail_shift_right(const struct xdr_buf *buf, unsigned int base, unsigned int len, unsigned int shift) @@ -577,6 +624,25 @@ static void xdr_buf_pages_shift_right(const struct xdr_buf *buf, xdr_buf_pages_copy_right(buf, base, len, shift); } +static void xdr_buf_head_shift_right(const struct xdr_buf *buf, + unsigned int base, unsigned int len, + unsigned int shift) +{ + const struct kvec *head = buf->head; + + if (!shift) + return; + if (base >= head->iov_len) { + xdr_buf_pages_shift_right(buf, head->iov_len - base, len, + shift); + return; + } + if (base + len > head->iov_len) + xdr_buf_pages_shift_right(buf, 0, base + len - head->iov_len, + shift); + xdr_buf_head_copy_right(buf, base, len, shift); +} + static void xdr_buf_tail_copy_left(const struct xdr_buf *buf, unsigned int base, unsigned int len, unsigned int shift) { @@ -683,86 +749,31 @@ static void xdr_buf_pages_shift_left(const struct xdr_buf *buf, /** * xdr_shrink_bufhead * @buf: xdr_buf - * @len: bytes to remove from buf->head[0] + * @len: new length of buf->head[0] * - * Shrinks XDR buffer's header kvec buf->head[0] by + * Shrinks XDR buffer's header kvec buf->head[0], setting it to * 'len' bytes. The extra data is not lost, but is instead * moved into the inlined pages and/or the tail. */ -static unsigned int -xdr_shrink_bufhead(struct xdr_buf *buf, size_t len) +static unsigned int xdr_shrink_bufhead(struct xdr_buf *buf, unsigned int len) { - struct kvec *head, *tail; - size_t copy, offs; - unsigned int pglen = buf->page_len; - unsigned int result; - - result = 0; - tail = buf->tail; - head = buf->head; + struct kvec *head = buf->head; + unsigned int shift, buflen = max(buf->len, len); WARN_ON_ONCE(len > head->iov_len); - if (len > head->iov_len) - len = head->iov_len; - - /* Shift the tail first */ - if (tail->iov_len != 0) { - if (tail->iov_len > len) { - copy = tail->iov_len - len; - memmove((char *)tail->iov_base + len, - tail->iov_base, copy); - result += copy; - } - /* Copy from the inlined pages into the tail */ - copy = len; - if (copy > pglen) - copy = pglen; - offs = len - copy; - if (offs >= tail->iov_len) - copy = 0; - else if (copy > tail->iov_len - offs) - copy = tail->iov_len - offs; - if (copy != 0) { - _copy_from_pages((char *)tail->iov_base + offs, - buf->pages, - buf->page_base + pglen + offs - len, - copy); - result += copy; - } - /* Do we also need to copy data from the head into the tail ? */ - if (len > pglen) { - offs = copy = len - pglen; - if (copy > tail->iov_len) - copy = tail->iov_len; - memcpy(tail->iov_base, - (char *)head->iov_base + - head->iov_len - offs, - copy); - result += copy; - } + if (head->iov_len > buflen) { + buf->buflen -= head->iov_len - buflen; + head->iov_len = buflen; } - /* Now handle pages */ - if (pglen != 0) { - if (pglen > len) - _shift_data_right_pages(buf->pages, - buf->page_base + len, - buf->page_base, - pglen - len); - copy = len; - if (len > pglen) - copy = pglen; - _copy_to_pages(buf->pages, buf->page_base, - (char *)head->iov_base + head->iov_len - len, - copy); - result += copy; - } - head->iov_len -= len; - buf->buflen -= len; - /* Have we truncated the message? */ - if (buf->len > buf->buflen) - buf->len = buf->buflen; - - return result; + if (len >= head->iov_len) + return 0; + shift = head->iov_len - len; + xdr_buf_try_expand(buf, shift); + xdr_buf_head_shift_right(buf, len, buflen - len, shift); + head->iov_len = len; + buf->buflen -= shift; + buf->len -= shift; + return shift; } /** @@ -798,7 +809,7 @@ static unsigned int xdr_shrink_pagelen(struct xdr_buf *buf, unsigned int len) void xdr_shift_buf(struct xdr_buf *buf, size_t len) { - xdr_shrink_bufhead(buf, len); + xdr_shrink_bufhead(buf, buf->head->iov_len - len); } EXPORT_SYMBOL_GPL(xdr_shift_buf); @@ -1371,13 +1382,12 @@ static void xdr_realign_pages(struct xdr_stream *xdr) struct xdr_buf *buf = xdr->buf; struct kvec *iov = buf->head; unsigned int cur = xdr_stream_pos(xdr); - unsigned int copied, offset; + unsigned int copied; /* Realign pages to current pointer position */ if (iov->iov_len > cur) { - offset = iov->iov_len - cur; - copied = xdr_shrink_bufhead(buf, offset); - trace_rpc_xdr_alignment(xdr, offset, copied); + copied = xdr_shrink_bufhead(buf, cur); + trace_rpc_xdr_alignment(xdr, cur, copied); xdr->nwords = XDR_QUADLEN(buf->len - cur); } }