renegade-project/linux-next
2
0
Fork 0
mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-22 12:14:01 +08:00
Code

SUNRPC: Fix xdr_expand_hole()

Browse Source 
We do want to try to grow the buffer if possible, but if that attempt
fails, we still want to move the data and truncate the XDR message.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
This commit is contained in:
Trond Myklebust 2020-12-04 17:15:09 -05:00
parent 9a20f6f4e6
commit c4f2f591f0
2 changed files with 178 additions and 94 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/linux/sunrpc/xdr.h
View File

@ -253,7 +253,7 @@ extern unsigned int xdr_read_pages(struct xdr_stream *xdr, unsigned int len);
extern void xdr_enter_page(struct xdr_stream *xdr, unsigned int len);
extern int xdr_process_buf(struct xdr_buf *buf, unsigned int offset, unsigned int len, int (*actor)(struct scatterlist *, void *), void *data);
extern unsigned int xdr_align_data(struct xdr_stream *, unsigned int offset, unsigned int length);
extern uint64_t xdr_expand_hole(struct xdr_stream *, uint64_t, uint64_t);
extern unsigned int xdr_expand_hole(struct xdr_stream *, unsigned int offset, unsigned int length);
/**
* xdr_stream_remaining - Return the number of bytes remaining in the stream

270
net/sunrpc/xdr.c
View File

@ -334,46 +334,6 @@ _shift_data_right_pages(struct page **pages, size_t pgto_base,
} while ((len -= copy) != 0);
}
static unsigned int
_shift_data_right_tail(struct xdr_buf *buf, unsigned int pgfrom, size_t len)
{
struct kvec *tail = buf->tail;
unsigned int tailbuf_len;
unsigned int result = 0;
size_t copy;
tailbuf_len = buf->buflen - buf->head->iov_len - buf->page_len;
/* Shift the tail first */
if (tailbuf_len != 0) {
unsigned int free_space = tailbuf_len - tail->iov_len;
if (len < free_space)
free_space = len;
if (len > free_space)
len = free_space;
tail->iov_len += free_space;
copy = len;
if (tail->iov_len > len) {
char *p = (char *)tail->iov_base + len;
memmove(p, tail->iov_base, tail->iov_len - free_space);
result += tail->iov_len - free_space;
} else
copy = tail->iov_len;
/* Copy from the inlined pages into the tail */
_copy_from_pages((char *)tail->iov_base,
buf->pages,
buf->page_base + pgfrom,
copy);
result += copy;
}
return result;
}
/**
* _copy_to_pages
* @pages: array of pages
@ -464,18 +424,42 @@ _copy_from_pages(char *p, struct page **pages, size_t pgbase, size_t len)
}
EXPORT_SYMBOL_GPL(_copy_from_pages);
static void xdr_buf_iov_zero(const struct kvec *iov, unsigned int base,
unsigned int len)
{
if (base >= iov->iov_len)
return;
if (len > iov->iov_len - base)
len = iov->iov_len - base;
memset(iov->iov_base + base, 0, len);
}
/**
* _zero_pages
* @pages: array of pages
* @pgbase: beginning page vector address
* xdr_buf_pages_zero
* @buf: xdr_buf
* @pgbase: beginning offset
* @len: length
*/
static void
_zero_pages(struct page **pages, size_t pgbase, size_t len)
static void xdr_buf_pages_zero(const struct xdr_buf *buf, unsigned int pgbase,
unsigned int len)
{
struct page **pages = buf->pages;
struct page **page;
char *vpage;
size_t zero;
unsigned int zero;
if (!len)
return;
if (pgbase >= buf->page_len) {
xdr_buf_iov_zero(buf->tail, pgbase - buf->page_len, len);
return;
}
if (pgbase + len > buf->page_len) {
xdr_buf_iov_zero(buf->tail, 0, pgbase + len - buf->page_len);
len = buf->page_len - pgbase;
}
pgbase += buf->page_base;
page = pages + (pgbase >> PAGE_SHIFT);
pgbase &= ~PAGE_MASK;
@ -496,6 +480,103 @@ _zero_pages(struct page **pages, size_t pgbase, size_t len)
} while ((len -= zero) != 0);
}
static void xdr_buf_try_expand(struct xdr_buf *buf, unsigned int len)
{
struct kvec *head = buf->head;
struct kvec *tail = buf->tail;
unsigned int sum = head->iov_len + buf->page_len + tail->iov_len;
unsigned int free_space;
if (sum > buf->len) {
free_space = min_t(unsigned int, sum - buf->len, len);
buf->len += free_space;
len -= free_space;
if (!len)
return;
}
if (buf->buflen > sum) {
/* Expand the tail buffer */
free_space = min_t(unsigned int, buf->buflen - sum, len);
tail->iov_len += free_space;
buf->len += free_space;
}
}
static void xdr_buf_tail_copy_right(const struct xdr_buf *buf,
unsigned int base, unsigned int len,
unsigned int shift)
{
const struct kvec *tail = buf->tail;
unsigned int to = base + shift;
if (to >= tail->iov_len)
return;
if (len + to > tail->iov_len)
len = tail->iov_len - to;
memmove(tail->iov_base + to, tail->iov_base + base, len);
}
static void xdr_buf_pages_copy_right(const struct xdr_buf *buf,
unsigned int base, unsigned int len,
unsigned int shift)
{
const struct kvec *tail = buf->tail;
unsigned int to = base + shift;
unsigned int pglen = 0;
unsigned int talen = 0, tato = 0;
if (base >= buf->page_len)
return;
if (len > buf->page_len - base)
len = buf->page_len - base;
if (to >= buf->page_len) {
tato = to - buf->page_len;
if (tail->iov_len >= len + tato)
talen = len;
else if (tail->iov_len > tato)
talen = tail->iov_len - tato;
} else if (len + to >= buf->page_len) {
pglen = buf->page_len - to;
talen = len - pglen;
if (talen > tail->iov_len)
talen = tail->iov_len;
} else
pglen = len;
_copy_from_pages(tail->iov_base + tato, buf->pages,
buf->page_base + base + pglen, talen);
_shift_data_right_pages(buf->pages, buf->page_base + to,
buf->page_base + base, pglen);
}
static void xdr_buf_tail_shift_right(const struct xdr_buf *buf,
unsigned int base, unsigned int len,
unsigned int shift)
{
const struct kvec *tail = buf->tail;
if (base >= tail->iov_len || !shift || !len)
return;
xdr_buf_tail_copy_right(buf, base, len, shift);
}
static void xdr_buf_pages_shift_right(const struct xdr_buf *buf,
unsigned int base, unsigned int len,
unsigned int shift)
{
if (!shift || !len)
return;
if (base >= buf->page_len) {
xdr_buf_tail_shift_right(buf, base - buf->page_len, len, shift);
return;
}
if (base + len > buf->page_len)
xdr_buf_tail_shift_right(buf, 0, base + len - buf->page_len,
shift);
xdr_buf_pages_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)
{
@ -685,30 +766,33 @@ xdr_shrink_bufhead(struct xdr_buf *buf, size_t len)
}
/**
* xdr_shrink_pagelen - shrinks buf->pages by up to @len bytes
* xdr_shrink_pagelen - shrinks buf->pages to @len bytes
* @buf: xdr_buf
* @len: bytes to remove from buf->pages
* @len: new page buffer length
*
* The extra data is not lost, but is instead moved into buf->tail.
* Returns the actual number of bytes moved.
*/
static unsigned int
xdr_shrink_pagelen(struct xdr_buf *buf, size_t len)
static unsigned int xdr_shrink_pagelen(struct xdr_buf *buf, unsigned int len)
{
unsigned int pglen = buf->page_len;
unsigned int result;
unsigned int shift, buflen = buf->len - buf->head->iov_len;
if (len > buf->page_len)
len = buf-> page_len;
result = _shift_data_right_tail(buf, pglen - len, len);
buf->page_len -= len;
buf->buflen -= len;
/* Have we truncated the message? */
if (buf->len > buf->buflen)
buf->len = buf->buflen;
return result;
WARN_ON_ONCE(len > buf->page_len);
if (buf->head->iov_len >= buf->len || len > buflen)
buflen = len;
if (buf->page_len > buflen) {
buf->buflen -= buf->page_len - buflen;
buf->page_len = buflen;
}
if (len >= buf->page_len)
return 0;
shift = buf->page_len - len;
xdr_buf_try_expand(buf, shift);
xdr_buf_pages_shift_right(buf, len, buflen - len, shift);
buf->page_len = len;
buf->len -= shift;
buf->buflen -= shift;
return shift;
}
void
@ -728,6 +812,18 @@ unsigned int xdr_stream_pos(const struct xdr_stream *xdr)
}
EXPORT_SYMBOL_GPL(xdr_stream_pos);
static void xdr_stream_set_pos(struct xdr_stream *xdr, unsigned int pos)
{
unsigned int blen = xdr->buf->len;
xdr->nwords = blen > pos ? XDR_QUADLEN(blen) - XDR_QUADLEN(pos) : 0;
}
static void xdr_stream_page_set_pos(struct xdr_stream *xdr, unsigned int pos)
{
xdr_stream_set_pos(xdr, pos + xdr->buf->head[0].iov_len);
}
/**
* xdr_page_pos - Return the current offset from the start of the xdr pages
* @xdr: pointer to struct xdr_stream
@ -1291,7 +1387,7 @@ static unsigned int xdr_align_pages(struct xdr_stream *xdr, unsigned int len)
struct xdr_buf *buf = xdr->buf;
unsigned int nwords = XDR_QUADLEN(len);
unsigned int cur = xdr_stream_pos(xdr);
unsigned int copied, offset;
unsigned int copied;
if (xdr->nwords == 0)
return 0;
@ -1305,9 +1401,8 @@ static unsigned int xdr_align_pages(struct xdr_stream *xdr, unsigned int len)
len = buf->page_len;
else if (nwords < xdr->nwords) {
/* Truncate page data and move it into the tail */
offset = buf->page_len - len;
copied = xdr_shrink_pagelen(buf, offset);
trace_rpc_xdr_alignment(xdr, offset, copied);
copied = xdr_shrink_pagelen(buf, len);
trace_rpc_xdr_alignment(xdr, len, copied);
xdr->nwords = XDR_QUADLEN(buf->len - cur);
}
return len;
@ -1387,39 +1482,28 @@ unsigned int xdr_align_data(struct xdr_stream *xdr, unsigned int offset,
}
EXPORT_SYMBOL_GPL(xdr_align_data);
uint64_t xdr_expand_hole(struct xdr_stream *xdr, uint64_t offset, uint64_t length)
unsigned int xdr_expand_hole(struct xdr_stream *xdr, unsigned int offset,
unsigned int length)
{
struct xdr_buf *buf = xdr->buf;
unsigned int bytes;
unsigned int from;
unsigned int truncated = 0;
if ((offset + length) < offset ||
(offset + length) > buf->page_len)
length = buf->page_len - offset;
unsigned int from, to, shift;
xdr_realign_pages(xdr);
from = xdr_page_pos(xdr);
bytes = xdr_stream_remaining(xdr);
to = xdr_align_size(offset + length);
if (offset + length + bytes > buf->page_len) {
unsigned int shift = (offset + length + bytes) - buf->page_len;
unsigned int res = _shift_data_right_tail(buf, from + bytes - shift, shift);
truncated = shift - res;
xdr->nwords -= XDR_QUADLEN(truncated);
bytes -= shift;
}
/* Could the hole be behind us? */
if (to > from) {
unsigned int buflen = buf->len - buf->head->iov_len;
shift = to - from;
xdr_buf_try_expand(buf, shift);
xdr_buf_pages_shift_right(buf, from, buflen, shift);
xdr_stream_page_set_pos(xdr, to);
} else if (to != from)
xdr_align_data(xdr, to, 0);
xdr_buf_pages_zero(buf, offset, length);
/* Now move the page data over and zero pages */
if (bytes > 0)
_shift_data_right_pages(buf->pages,
buf->page_base + offset + length,
buf->page_base + from,
bytes);
_zero_pages(buf->pages, buf->page_base + offset, length);
buf->len += length - (from - offset) - truncated;
xdr_set_page(xdr, offset + length, xdr_stream_remaining(xdr));
xdr_set_page(xdr, to, xdr_stream_remaining(xdr));
return length;
}
EXPORT_SYMBOL_GPL(xdr_expand_hole);