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-rw-r--r--net/sunrpc/xdr.c570
1 files changed, 464 insertions, 106 deletions
diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
index cd9e841e749..23fb4e75e24 100644
--- a/net/sunrpc/xdr.c
+++ b/net/sunrpc/xdr.c
@@ -122,39 +122,11 @@ xdr_terminate_string(struct xdr_buf *buf, const u32 len)
{
char *kaddr;
- kaddr = kmap_atomic(buf->pages[0], KM_USER0);
+ kaddr = kmap_atomic(buf->pages[0]);
kaddr[buf->page_base + len] = '\0';
- kunmap_atomic(kaddr, KM_USER0);
+ kunmap_atomic(kaddr);
}
-EXPORT_SYMBOL(xdr_terminate_string);
-
-void
-xdr_encode_pages(struct xdr_buf *xdr, struct page **pages, unsigned int base,
- unsigned int len)
-{
- struct kvec *tail = xdr->tail;
- u32 *p;
-
- xdr->pages = pages;
- xdr->page_base = base;
- xdr->page_len = len;
-
- p = (u32 *)xdr->head[0].iov_base + XDR_QUADLEN(xdr->head[0].iov_len);
- tail->iov_base = p;
- tail->iov_len = 0;
-
- if (len & 3) {
- unsigned int pad = 4 - (len & 3);
-
- *p = 0;
- tail->iov_base = (char *)p + (len & 3);
- tail->iov_len = pad;
- len += pad;
- }
- xdr->buflen += len;
- xdr->len += len;
-}
-EXPORT_SYMBOL_GPL(xdr_encode_pages);
+EXPORT_SYMBOL_GPL(xdr_terminate_string);
void
xdr_inline_pages(struct xdr_buf *xdr, unsigned int offset,
@@ -180,7 +152,9 @@ EXPORT_SYMBOL_GPL(xdr_inline_pages);
/*
* Helper routines for doing 'memmove' like operations on a struct xdr_buf
- *
+ */
+
+/**
* _shift_data_right_pages
* @pages: vector of pages containing both the source and dest memory area.
* @pgto_base: page vector address of destination
@@ -232,17 +206,20 @@ _shift_data_right_pages(struct page **pages, size_t pgto_base,
pgto_base -= copy;
pgfrom_base -= copy;
- vto = kmap_atomic(*pgto, KM_USER0);
- vfrom = kmap_atomic(*pgfrom, KM_USER1);
- memmove(vto + pgto_base, vfrom + pgfrom_base, copy);
+ vto = kmap_atomic(*pgto);
+ if (*pgto != *pgfrom) {
+ vfrom = kmap_atomic(*pgfrom);
+ memcpy(vto + pgto_base, vfrom + pgfrom_base, copy);
+ kunmap_atomic(vfrom);
+ } else
+ memmove(vto + pgto_base, vto + pgfrom_base, copy);
flush_dcache_page(*pgto);
- kunmap_atomic(vfrom, KM_USER1);
- kunmap_atomic(vto, KM_USER0);
+ kunmap_atomic(vto);
} while ((len -= copy) != 0);
}
-/*
+/**
* _copy_to_pages
* @pages: array of pages
* @pgbase: page vector address of destination
@@ -267,9 +244,9 @@ _copy_to_pages(struct page **pages, size_t pgbase, const char *p, size_t len)
if (copy > len)
copy = len;
- vto = kmap_atomic(*pgto, KM_USER0);
+ vto = kmap_atomic(*pgto);
memcpy(vto + pgbase, p, copy);
- kunmap_atomic(vto, KM_USER0);
+ kunmap_atomic(vto);
len -= copy;
if (len == 0)
@@ -286,7 +263,7 @@ _copy_to_pages(struct page **pages, size_t pgbase, const char *p, size_t len)
flush_dcache_page(*pgto);
}
-/*
+/**
* _copy_from_pages
* @p: pointer to destination
* @pages: array of pages
@@ -296,7 +273,7 @@ _copy_to_pages(struct page **pages, size_t pgbase, const char *p, size_t len)
* Copies data into an arbitrary memory location from an array of pages
* The copy is assumed to be non-overlapping.
*/
-static void
+void
_copy_from_pages(char *p, struct page **pages, size_t pgbase, size_t len)
{
struct page **pgfrom;
@@ -311,9 +288,9 @@ _copy_from_pages(char *p, struct page **pages, size_t pgbase, size_t len)
if (copy > len)
copy = len;
- vfrom = kmap_atomic(*pgfrom, KM_USER0);
+ vfrom = kmap_atomic(*pgfrom);
memcpy(p, vfrom + pgbase, copy);
- kunmap_atomic(vfrom, KM_USER0);
+ kunmap_atomic(vfrom);
pgbase += copy;
if (pgbase == PAGE_CACHE_SIZE) {
@@ -324,8 +301,9 @@ _copy_from_pages(char *p, struct page **pages, size_t pgbase, size_t len)
} while ((len -= copy) != 0);
}
+EXPORT_SYMBOL_GPL(_copy_from_pages);
-/*
+/**
* xdr_shrink_bufhead
* @buf: xdr_buf
* @len: bytes to remove from buf->head[0]
@@ -343,7 +321,10 @@ xdr_shrink_bufhead(struct xdr_buf *buf, size_t len)
tail = buf->tail;
head = buf->head;
- BUG_ON (len > head->iov_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) {
@@ -398,7 +379,7 @@ xdr_shrink_bufhead(struct xdr_buf *buf, size_t len)
buf->len = buf->buflen;
}
-/*
+/**
* xdr_shrink_pagelen
* @buf: xdr_buf
* @len: bytes to remove from buf->pages
@@ -454,6 +435,16 @@ xdr_shift_buf(struct xdr_buf *buf, size_t len)
EXPORT_SYMBOL_GPL(xdr_shift_buf);
/**
+ * xdr_stream_pos - Return the current offset from the start of the xdr_stream
+ * @xdr: pointer to struct xdr_stream
+ */
+unsigned int xdr_stream_pos(const struct xdr_stream *xdr)
+{
+ return (unsigned int)(XDR_QUADLEN(xdr->buf->len) - xdr->nwords) << 2;
+}
+EXPORT_SYMBOL_GPL(xdr_stream_pos);
+
+/**
* xdr_init_encode - Initialize a struct xdr_stream for sending data.
* @xdr: pointer to xdr_stream struct
* @buf: pointer to XDR buffer in which to encode data
@@ -471,6 +462,7 @@ void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p)
struct kvec *iov = buf->head;
int scratch_len = buf->buflen - buf->page_len - buf->tail[0].iov_len;
+ xdr_set_scratch_buffer(xdr, NULL, 0);
BUG_ON(scratch_len < 0);
xdr->buf = buf;
xdr->iov = iov;
@@ -491,6 +483,73 @@ void xdr_init_encode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p)
EXPORT_SYMBOL_GPL(xdr_init_encode);
/**
+ * xdr_commit_encode - Ensure all data is written to buffer
+ * @xdr: pointer to xdr_stream
+ *
+ * We handle encoding across page boundaries by giving the caller a
+ * temporary location to write to, then later copying the data into
+ * place; xdr_commit_encode does that copying.
+ *
+ * Normally the caller doesn't need to call this directly, as the
+ * following xdr_reserve_space will do it. But an explicit call may be
+ * required at the end of encoding, or any other time when the xdr_buf
+ * data might be read.
+ */
+void xdr_commit_encode(struct xdr_stream *xdr)
+{
+ int shift = xdr->scratch.iov_len;
+ void *page;
+
+ if (shift == 0)
+ return;
+ page = page_address(*xdr->page_ptr);
+ memcpy(xdr->scratch.iov_base, page, shift);
+ memmove(page, page + shift, (void *)xdr->p - page);
+ xdr->scratch.iov_len = 0;
+}
+EXPORT_SYMBOL_GPL(xdr_commit_encode);
+
+__be32 *xdr_get_next_encode_buffer(struct xdr_stream *xdr, size_t nbytes)
+{
+ static __be32 *p;
+ int space_left;
+ int frag1bytes, frag2bytes;
+
+ if (nbytes > PAGE_SIZE)
+ return NULL; /* Bigger buffers require special handling */
+ if (xdr->buf->len + nbytes > xdr->buf->buflen)
+ return NULL; /* Sorry, we're totally out of space */
+ frag1bytes = (xdr->end - xdr->p) << 2;
+ frag2bytes = nbytes - frag1bytes;
+ if (xdr->iov)
+ xdr->iov->iov_len += frag1bytes;
+ else
+ xdr->buf->page_len += frag1bytes;
+ xdr->page_ptr++;
+ xdr->iov = NULL;
+ /*
+ * If the last encode didn't end exactly on a page boundary, the
+ * next one will straddle boundaries. Encode into the next
+ * page, then copy it back later in xdr_commit_encode. We use
+ * the "scratch" iov to track any temporarily unused fragment of
+ * space at the end of the previous buffer:
+ */
+ xdr->scratch.iov_base = xdr->p;
+ xdr->scratch.iov_len = frag1bytes;
+ p = page_address(*xdr->page_ptr);
+ /*
+ * Note this is where the next encode will start after we've
+ * shifted this one back:
+ */
+ xdr->p = (void *)p + frag2bytes;
+ space_left = xdr->buf->buflen - xdr->buf->len;
+ xdr->end = (void *)p + min_t(int, space_left, PAGE_SIZE);
+ xdr->buf->page_len += frag2bytes;
+ xdr->buf->len += nbytes;
+ return p;
+}
+
+/**
* xdr_reserve_space - Reserve buffer space for sending
* @xdr: pointer to xdr_stream
* @nbytes: number of bytes to reserve
@@ -504,20 +563,122 @@ __be32 * xdr_reserve_space(struct xdr_stream *xdr, size_t nbytes)
__be32 *p = xdr->p;
__be32 *q;
+ xdr_commit_encode(xdr);
/* align nbytes on the next 32-bit boundary */
nbytes += 3;
nbytes &= ~3;
q = p + (nbytes >> 2);
if (unlikely(q > xdr->end || q < p))
- return NULL;
+ return xdr_get_next_encode_buffer(xdr, nbytes);
xdr->p = q;
- xdr->iov->iov_len += nbytes;
+ if (xdr->iov)
+ xdr->iov->iov_len += nbytes;
+ else
+ xdr->buf->page_len += nbytes;
xdr->buf->len += nbytes;
return p;
}
EXPORT_SYMBOL_GPL(xdr_reserve_space);
/**
+ * xdr_truncate_encode - truncate an encode buffer
+ * @xdr: pointer to xdr_stream
+ * @len: new length of buffer
+ *
+ * Truncates the xdr stream, so that xdr->buf->len == len,
+ * and xdr->p points at offset len from the start of the buffer, and
+ * head, tail, and page lengths are adjusted to correspond.
+ *
+ * If this means moving xdr->p to a different buffer, we assume that
+ * that the end pointer should be set to the end of the current page,
+ * except in the case of the head buffer when we assume the head
+ * buffer's current length represents the end of the available buffer.
+ *
+ * This is *not* safe to use on a buffer that already has inlined page
+ * cache pages (as in a zero-copy server read reply), except for the
+ * simple case of truncating from one position in the tail to another.
+ *
+ */
+void xdr_truncate_encode(struct xdr_stream *xdr, size_t len)
+{
+ struct xdr_buf *buf = xdr->buf;
+ struct kvec *head = buf->head;
+ struct kvec *tail = buf->tail;
+ int fraglen;
+ int new, old;
+
+ if (len > buf->len) {
+ WARN_ON_ONCE(1);
+ return;
+ }
+ xdr_commit_encode(xdr);
+
+ fraglen = min_t(int, buf->len - len, tail->iov_len);
+ tail->iov_len -= fraglen;
+ buf->len -= fraglen;
+ if (tail->iov_len && buf->len == len) {
+ xdr->p = tail->iov_base + tail->iov_len;
+ /* xdr->end, xdr->iov should be set already */
+ return;
+ }
+ WARN_ON_ONCE(fraglen);
+ fraglen = min_t(int, buf->len - len, buf->page_len);
+ buf->page_len -= fraglen;
+ buf->len -= fraglen;
+
+ new = buf->page_base + buf->page_len;
+ old = new + fraglen;
+ xdr->page_ptr -= (old >> PAGE_SHIFT) - (new >> PAGE_SHIFT);
+
+ if (buf->page_len && buf->len == len) {
+ xdr->p = page_address(*xdr->page_ptr);
+ xdr->end = (void *)xdr->p + PAGE_SIZE;
+ xdr->p = (void *)xdr->p + (new % PAGE_SIZE);
+ /* xdr->iov should already be NULL */
+ return;
+ }
+ if (fraglen) {
+ xdr->end = head->iov_base + head->iov_len;
+ xdr->page_ptr--;
+ }
+ /* (otherwise assume xdr->end is already set) */
+ head->iov_len = len;
+ buf->len = len;
+ xdr->p = head->iov_base + head->iov_len;
+ xdr->iov = buf->head;
+}
+EXPORT_SYMBOL(xdr_truncate_encode);
+
+/**
+ * xdr_restrict_buflen - decrease available buffer space
+ * @xdr: pointer to xdr_stream
+ * @newbuflen: new maximum number of bytes available
+ *
+ * Adjust our idea of how much space is available in the buffer.
+ * If we've already used too much space in the buffer, returns -1.
+ * If the available space is already smaller than newbuflen, returns 0
+ * and does nothing. Otherwise, adjusts xdr->buf->buflen to newbuflen
+ * and ensures xdr->end is set at most offset newbuflen from the start
+ * of the buffer.
+ */
+int xdr_restrict_buflen(struct xdr_stream *xdr, int newbuflen)
+{
+ struct xdr_buf *buf = xdr->buf;
+ int left_in_this_buf = (void *)xdr->end - (void *)xdr->p;
+ int end_offset = buf->len + left_in_this_buf;
+
+ if (newbuflen < 0 || newbuflen < buf->len)
+ return -1;
+ if (newbuflen > buf->buflen)
+ return 0;
+ if (newbuflen < end_offset)
+ xdr->end = (void *)xdr->end + newbuflen - end_offset;
+ buf->buflen = newbuflen;
+ return 0;
+}
+EXPORT_SYMBOL(xdr_restrict_buflen);
+
+/**
* xdr_write_pages - Insert a list of pages into an XDR buffer for sending
* @xdr: pointer to xdr_stream
* @pages: list of pages
@@ -552,6 +713,72 @@ 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)
+{
+ if (len > iov->iov_len)
+ len = iov->iov_len;
+ xdr->p = (__be32*)iov->iov_base;
+ xdr->end = (__be32*)(iov->iov_base + len);
+ xdr->iov = iov;
+ xdr->page_ptr = NULL;
+}
+
+static int xdr_set_page_base(struct xdr_stream *xdr,
+ unsigned int base, unsigned int len)
+{
+ unsigned int pgnr;
+ unsigned int maxlen;
+ unsigned int pgoff;
+ unsigned int pgend;
+ void *kaddr;
+
+ maxlen = xdr->buf->page_len;
+ if (base >= maxlen)
+ return -EINVAL;
+ maxlen -= base;
+ if (len > maxlen)
+ len = maxlen;
+
+ base += xdr->buf->page_base;
+
+ pgnr = base >> PAGE_SHIFT;
+ xdr->page_ptr = &xdr->buf->pages[pgnr];
+ kaddr = page_address(*xdr->page_ptr);
+
+ pgoff = base & ~PAGE_MASK;
+ xdr->p = (__be32*)(kaddr + pgoff);
+
+ pgend = pgoff + len;
+ if (pgend > PAGE_SIZE)
+ pgend = PAGE_SIZE;
+ xdr->end = (__be32*)(kaddr + pgend);
+ xdr->iov = NULL;
+ return 0;
+}
+
+static void xdr_set_next_page(struct xdr_stream *xdr)
+{
+ unsigned int newbase;
+
+ newbase = (1 + xdr->page_ptr - xdr->buf->pages) << PAGE_SHIFT;
+ newbase -= xdr->buf->page_base;
+
+ if (xdr_set_page_base(xdr, newbase, PAGE_SIZE) < 0)
+ xdr_set_iov(xdr, xdr->buf->tail, xdr->buf->len);
+}
+
+static bool xdr_set_next_buffer(struct xdr_stream *xdr)
+{
+ if (xdr->page_ptr != NULL)
+ xdr_set_next_page(xdr);
+ else if (xdr->iov == xdr->buf->head) {
+ if (xdr_set_page_base(xdr, 0, PAGE_SIZE) < 0)
+ xdr_set_iov(xdr, xdr->buf->tail, xdr->buf->len);
+ }
+ return xdr->p != xdr->end;
+}
+
/**
* xdr_init_decode - Initialize an xdr_stream for decoding data.
* @xdr: pointer to xdr_stream struct
@@ -560,41 +787,93 @@ EXPORT_SYMBOL_GPL(xdr_write_pages);
*/
void xdr_init_decode(struct xdr_stream *xdr, struct xdr_buf *buf, __be32 *p)
{
- struct kvec *iov = buf->head;
- unsigned int len = iov->iov_len;
-
- if (len > buf->len)
- len = buf->len;
xdr->buf = buf;
- xdr->iov = iov;
- xdr->p = p;
- xdr->end = (__be32 *)((char *)iov->iov_base + len);
+ 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);
+ if (p != NULL && p > xdr->p && xdr->end >= p) {
+ xdr->nwords -= p - xdr->p;
+ xdr->p = p;
+ }
}
EXPORT_SYMBOL_GPL(xdr_init_decode);
/**
- * xdr_inline_peek - Allow read-ahead in the XDR data stream
+ * xdr_init_decode - Initialize an xdr_stream for decoding data.
* @xdr: pointer to xdr_stream struct
- * @nbytes: number of bytes of data to decode
- *
- * Check if the input buffer is long enough to enable us to decode
- * 'nbytes' more bytes of data starting at the current position.
- * If so return the current pointer without updating the current
- * pointer position.
+ * @buf: pointer to XDR buffer from which to decode data
+ * @pages: list of pages to decode into
+ * @len: length in bytes of buffer in pages
*/
-__be32 * xdr_inline_peek(struct xdr_stream *xdr, size_t nbytes)
+void xdr_init_decode_pages(struct xdr_stream *xdr, struct xdr_buf *buf,
+ struct page **pages, unsigned int len)
+{
+ memset(buf, 0, sizeof(*buf));
+ buf->pages = pages;
+ buf->page_len = len;
+ buf->buflen = len;
+ buf->len = len;
+ xdr_init_decode(xdr, buf, NULL);
+}
+EXPORT_SYMBOL_GPL(xdr_init_decode_pages);
+
+static __be32 * __xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
{
+ unsigned int nwords = XDR_QUADLEN(nbytes);
__be32 *p = xdr->p;
- __be32 *q = p + XDR_QUADLEN(nbytes);
+ __be32 *q = p + nwords;
- if (unlikely(q > xdr->end || q < p))
+ if (unlikely(nwords > xdr->nwords || q > xdr->end || q < p))
return NULL;
+ xdr->p = q;
+ xdr->nwords -= nwords;
return p;
}
-EXPORT_SYMBOL_GPL(xdr_inline_peek);
/**
- * xdr_inline_decode - Retrieve non-page XDR data to decode
+ * xdr_set_scratch_buffer - Attach a scratch buffer for decoding data.
+ * @xdr: pointer to xdr_stream struct
+ * @buf: pointer to an empty buffer
+ * @buflen: size of 'buf'
+ *
+ * The scratch buffer is used when decoding from an array of pages.
+ * If an xdr_inline_decode() call spans across page boundaries, then
+ * we copy the data into the scratch buffer in order to allow linear
+ * access.
+ */
+void xdr_set_scratch_buffer(struct xdr_stream *xdr, void *buf, size_t buflen)
+{
+ xdr->scratch.iov_base = buf;
+ xdr->scratch.iov_len = buflen;
+}
+EXPORT_SYMBOL_GPL(xdr_set_scratch_buffer);
+
+static __be32 *xdr_copy_to_scratch(struct xdr_stream *xdr, size_t nbytes)
+{
+ __be32 *p;
+ void *cpdest = xdr->scratch.iov_base;
+ size_t cplen = (char *)xdr->end - (char *)xdr->p;
+
+ if (nbytes > xdr->scratch.iov_len)
+ return NULL;
+ memcpy(cpdest, xdr->p, cplen);
+ cpdest += cplen;
+ nbytes -= cplen;
+ if (!xdr_set_next_buffer(xdr))
+ return NULL;
+ p = __xdr_inline_decode(xdr, nbytes);
+ if (p == NULL)
+ return NULL;
+ memcpy(cpdest, p, nbytes);
+ return xdr->scratch.iov_base;
+}
+
+/**
+ * xdr_inline_decode - Retrieve XDR data to decode
* @xdr: pointer to xdr_stream struct
* @nbytes: number of bytes of data to decode
*
@@ -605,16 +884,49 @@ EXPORT_SYMBOL_GPL(xdr_inline_peek);
*/
__be32 * xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
{
- __be32 *p = xdr->p;
- __be32 *q = p + XDR_QUADLEN(nbytes);
+ __be32 *p;
- if (unlikely(q > xdr->end || q < p))
+ if (nbytes == 0)
+ return xdr->p;
+ if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
return NULL;
- xdr->p = q;
- return p;
+ p = __xdr_inline_decode(xdr, nbytes);
+ if (p != NULL)
+ return p;
+ return xdr_copy_to_scratch(xdr, nbytes);
}
EXPORT_SYMBOL_GPL(xdr_inline_decode);
+static unsigned int xdr_align_pages(struct xdr_stream *xdr, unsigned int len)
+{
+ struct xdr_buf *buf = xdr->buf;
+ struct kvec *iov;
+ unsigned int nwords = XDR_QUADLEN(len);
+ unsigned int cur = xdr_stream_pos(xdr);
+
+ if (xdr->nwords == 0)
+ return 0;
+ /* Realign pages to current pointer position */
+ iov = buf->head;
+ if (iov->iov_len > cur) {
+ xdr_shrink_bufhead(buf, iov->iov_len - cur);
+ xdr->nwords = XDR_QUADLEN(buf->len - cur);
+ }
+
+ if (nwords > xdr->nwords) {
+ nwords = xdr->nwords;
+ len = nwords << 2;
+ }
+ if (buf->page_len <= len)
+ len = buf->page_len;
+ else if (nwords < xdr->nwords) {
+ /* Truncate page data and move it into the tail */
+ xdr_shrink_pagelen(buf, buf->page_len - len);
+ xdr->nwords = XDR_QUADLEN(buf->len - cur);
+ }
+ return len;
+}
+
/**
* xdr_read_pages - Ensure page-based XDR data to decode is aligned at current pointer position
* @xdr: pointer to xdr_stream struct
@@ -623,39 +935,37 @@ EXPORT_SYMBOL_GPL(xdr_inline_decode);
* Moves data beyond the current pointer position from the XDR head[] buffer
* into the page list. Any data that lies beyond current position + "len"
* bytes is moved into the XDR tail[].
+ *
+ * Returns the number of XDR encoded bytes now contained in the pages
*/
-void xdr_read_pages(struct xdr_stream *xdr, unsigned int len)
+unsigned int xdr_read_pages(struct xdr_stream *xdr, unsigned int len)
{
struct xdr_buf *buf = xdr->buf;
struct kvec *iov;
- ssize_t shift;
+ unsigned int nwords;
unsigned int end;
- int padding;
+ unsigned int padding;
- /* Realign pages to current pointer position */
- iov = buf->head;
- shift = iov->iov_len + (char *)iov->iov_base - (char *)xdr->p;
- if (shift > 0)
- xdr_shrink_bufhead(buf, shift);
-
- /* Truncate page data and move it into the tail */
- if (buf->page_len > len)
- xdr_shrink_pagelen(buf, buf->page_len - len);
- padding = (XDR_QUADLEN(len) << 2) - len;
+ len = xdr_align_pages(xdr, len);
+ if (len == 0)
+ return 0;
+ nwords = XDR_QUADLEN(len);
+ padding = (nwords << 2) - len;
xdr->iov = iov = buf->tail;
/* Compute remaining message length. */
- end = iov->iov_len;
- shift = buf->buflen - buf->len;
- if (shift < end)
- end -= shift;
- else if (shift > 0)
- end = 0;
+ end = ((xdr->nwords - nwords) << 2) + padding;
+ if (end > iov->iov_len)
+ end = iov->iov_len;
+
/*
* Position current pointer at beginning of tail, and
* set remaining message length.
*/
xdr->p = (__be32 *)((char *)iov->iov_base + padding);
xdr->end = (__be32 *)((char *)iov->iov_base + end);
+ xdr->page_ptr = NULL;
+ xdr->nwords = XDR_QUADLEN(end - padding);
+ return len;
}
EXPORT_SYMBOL_GPL(xdr_read_pages);
@@ -671,16 +981,13 @@ EXPORT_SYMBOL_GPL(xdr_read_pages);
*/
void xdr_enter_page(struct xdr_stream *xdr, unsigned int len)
{
- char * kaddr = page_address(xdr->buf->pages[0]);
- xdr_read_pages(xdr, len);
+ len = xdr_align_pages(xdr, len);
/*
* Position current pointer at beginning of tail, and
* set remaining message length.
*/
- if (len > PAGE_CACHE_SIZE - xdr->buf->page_base)
- len = PAGE_CACHE_SIZE - xdr->buf->page_base;
- xdr->p = (__be32 *)(kaddr + xdr->buf->page_base);
- xdr->end = (__be32 *)((char *)xdr->p + len);
+ if (len != 0)
+ xdr_set_page_base(xdr, 0, len);
}
EXPORT_SYMBOL_GPL(xdr_enter_page);
@@ -696,8 +1003,20 @@ xdr_buf_from_iov(struct kvec *iov, struct xdr_buf *buf)
}
EXPORT_SYMBOL_GPL(xdr_buf_from_iov);
-/* Sets subbuf to the portion of buf of length len beginning base bytes
- * from the start of buf. Returns -1 if base of length are out of bounds. */
+/**
+ * xdr_buf_subsegment - set subbuf to a portion of buf
+ * @buf: an xdr buffer
+ * @subbuf: the result buffer
+ * @base: beginning of range in bytes
+ * @len: length of range in bytes
+ *
+ * sets @subbuf to an xdr buffer representing the portion of @buf of
+ * length @len starting at offset @base.
+ *
+ * @buf and @subbuf may be pointers to the same struct xdr_buf.
+ *
+ * Returns -1 if base of length are out of bounds.
+ */
int
xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf,
unsigned int base, unsigned int len)
@@ -710,9 +1029,8 @@ xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf,
len -= subbuf->head[0].iov_len;
base = 0;
} else {
- subbuf->head[0].iov_base = NULL;
- subbuf->head[0].iov_len = 0;
base -= buf->head[0].iov_len;
+ subbuf->head[0].iov_len = 0;
}
if (base < buf->page_len) {
@@ -734,9 +1052,8 @@ xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf,
len -= subbuf->tail[0].iov_len;
base = 0;
} else {
- subbuf->tail[0].iov_base = NULL;
- subbuf->tail[0].iov_len = 0;
base -= buf->tail[0].iov_len;
+ subbuf->tail[0].iov_len = 0;
}
if (base || len)
@@ -745,6 +1062,47 @@ xdr_buf_subsegment(struct xdr_buf *buf, struct xdr_buf *subbuf,
}
EXPORT_SYMBOL_GPL(xdr_buf_subsegment);
+/**
+ * xdr_buf_trim - lop at most "len" bytes off the end of "buf"
+ * @buf: buf to be trimmed
+ * @len: number of bytes to reduce "buf" by
+ *
+ * Trim an xdr_buf by the given number of bytes by fixing up the lengths. Note
+ * that it's possible that we'll trim less than that amount if the xdr_buf is
+ * too small, or if (for instance) it's all in the head and the parser has
+ * already read too far into it.
+ */
+void xdr_buf_trim(struct xdr_buf *buf, unsigned int len)
+{
+ size_t cur;
+ unsigned int trim = len;
+
+ if (buf->tail[0].iov_len) {
+ cur = min_t(size_t, buf->tail[0].iov_len, trim);
+ buf->tail[0].iov_len -= cur;
+ trim -= cur;
+ if (!trim)
+ goto fix_len;
+ }
+
+ if (buf->page_len) {
+ cur = min_t(unsigned int, buf->page_len, trim);
+ buf->page_len -= cur;
+ trim -= cur;
+ if (!trim)
+ goto fix_len;
+ }
+
+ if (buf->head[0].iov_len) {
+ cur = min_t(size_t, buf->head[0].iov_len, trim);
+ buf->head[0].iov_len -= cur;
+ trim -= cur;
+ }
+fix_len:
+ buf->len -= (len - trim);
+}
+EXPORT_SYMBOL_GPL(xdr_buf_trim);
+
static void __read_bytes_from_xdr_buf(struct xdr_buf *subbuf, void *obj, unsigned int len)
{
unsigned int this_len;
@@ -1091,7 +1449,7 @@ xdr_process_buf(struct xdr_buf *buf, unsigned int offset, unsigned int len,
int (*actor)(struct scatterlist *, void *), void *data)
{
int i, ret = 0;
- unsigned page_len, thislen, page_offset;
+ unsigned int page_len, thislen, page_offset;
struct scatterlist sg[1];
sg_init_table(sg, 1);
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-11-04 01:48:47 +0000