1 files changed, 267 insertions, 38 deletions

diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
index be11d672b5b9..3feff529a764 100644
--- a/net/sunrpc/xdr.c
+++ b/net/sunrpc/xdr.c
@@ -19,6 +19,9 @@
 #include <linux/bvec.h>
 #include <trace/events/sunrpc.h>
 
+static void _copy_to_pages(struct page **, size_t, const char *, size_t);
+
+
 /*
  * XDR functions for basic NFS types
  */
@@ -202,6 +205,88 @@ EXPORT_SYMBOL_GPL(xdr_inline_pages);
  */
 
 /**
+ * _shift_data_left_pages
+ * @pages: vector of pages containing both the source and dest memory area.
+ * @pgto_base: page vector address of destination
+ * @pgfrom_base: page vector address of source
+ * @len: number of bytes to copy
+ *
+ * Note: the addresses pgto_base and pgfrom_base are both calculated in
+ *       the same way:
+ *            if a memory area starts at byte 'base' in page 'pages[i]',
+ *            then its address is given as (i << PAGE_CACHE_SHIFT) + base
+ * Alse note: pgto_base must be < pgfrom_base, but the memory areas
+ * 	they point to may overlap.
+ */
+static void
+_shift_data_left_pages(struct page **pages, size_t pgto_base,
+			size_t pgfrom_base, size_t len)
+{
+	struct page **pgfrom, **pgto;
+	char *vfrom, *vto;
+	size_t copy;
+
+	BUG_ON(pgfrom_base <= pgto_base);
+
+	pgto = pages + (pgto_base >> PAGE_SHIFT);
+	pgfrom = pages + (pgfrom_base >> PAGE_SHIFT);
+
+	pgto_base &= ~PAGE_MASK;
+	pgfrom_base &= ~PAGE_MASK;
+
+	do {
+		if (pgto_base >= PAGE_SIZE) {
+			pgto_base = 0;
+			pgto++;
+		}
+		if (pgfrom_base >= PAGE_SIZE){
+			pgfrom_base = 0;
+			pgfrom++;
+		}
+
+		copy = len;
+		if (copy > (PAGE_SIZE - pgto_base))
+			copy = PAGE_SIZE - pgto_base;
+		if (copy > (PAGE_SIZE - pgfrom_base))
+			copy = PAGE_SIZE - pgfrom_base;
+
+		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(vto);
+
+		pgto_base += copy;
+		pgfrom_base += copy;
+
+	} while ((len -= copy) != 0);
+}
+
+static void
+_shift_data_left_tail(struct xdr_buf *buf, unsigned int pgto, size_t len)
+{
+	struct kvec *tail = buf->tail;
+
+	if (len > tail->iov_len)
+		len = tail->iov_len;
+
+	_copy_to_pages(buf->pages,
+		       buf->page_base + pgto,
+		       (char *)tail->iov_base,
+		       len);
+	tail->iov_len -= len;
+
+	if (tail->iov_len > 0)
+		memmove((char *)tail->iov_base,
+				tail->iov_base + len,
+				tail->iov_len);
+}
+
+/**
  * _shift_data_right_pages
  * @pages: vector of pages containing both the source and dest memory area.
  * @pgto_base: page vector address of destination
@@ -266,6 +351,46 @@ _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
@@ -351,6 +476,38 @@ _copy_from_pages(char *p, struct page **pages, size_t pgbase, size_t len)
 EXPORT_SYMBOL_GPL(_copy_from_pages);
 
 /**
+ * _zero_pages
+ * @pages: array of pages
+ * @pgbase: beginning page vector address
+ * @len: length
+ */
+static void
+_zero_pages(struct page **pages, size_t pgbase, size_t len)
+{
+	struct page **page;
+	char *vpage;
+	size_t zero;
+
+	page = pages + (pgbase >> PAGE_SHIFT);
+	pgbase &= ~PAGE_MASK;
+
+	do {
+		zero = PAGE_SIZE - pgbase;
+		if (zero > len)
+			zero = len;
+
+		vpage = kmap_atomic(*page);
+		memset(vpage + pgbase, 0, zero);
+		kunmap_atomic(vpage);
+
+		flush_dcache_page(*page);
+		pgbase = 0;
+		page++;
+
+	} while ((len -= zero) != 0);
+}
+
+/**
  * xdr_shrink_bufhead
  * @buf: xdr_buf
  * @len: bytes to remove from buf->head[0]
@@ -446,39 +603,13 @@ xdr_shrink_bufhead(struct xdr_buf *buf, size_t len)
 static unsigned int
 xdr_shrink_pagelen(struct xdr_buf *buf, size_t len)
 {
-	struct kvec *tail;
-	size_t copy;
 	unsigned int pglen = buf->page_len;
-	unsigned int tailbuf_len;
 	unsigned int result;
 
-	result = 0;
-	tail = buf->tail;
 	if (len > buf->page_len)
 		len = buf-> page_len;
-	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;
-		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 - len);
-			result += tail->iov_len - len;
-		} 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 + pglen - len,
-				copy);
-		result += copy;
-	}
+	result = _shift_data_right_tail(buf, pglen - len, len);
 	buf->page_len -= len;
 	buf->buflen -= len;
 	/* Have we truncated the message? */
@@ -506,6 +637,19 @@ unsigned int xdr_stream_pos(const struct xdr_stream *xdr)
 EXPORT_SYMBOL_GPL(xdr_stream_pos);
 
 /**
+ * xdr_page_pos - Return the current offset from the start of the xdr pages
+ * @xdr: pointer to struct xdr_stream
+ */
+unsigned int xdr_page_pos(const struct xdr_stream *xdr)
+{
+	unsigned int pos = xdr_stream_pos(xdr);
+
+	WARN_ON(pos < xdr->buf->head[0].iov_len);
+	return pos - xdr->buf->head[0].iov_len;
+}
+EXPORT_SYMBOL_GPL(xdr_page_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
@@ -825,6 +969,13 @@ static int xdr_set_page_base(struct xdr_stream *xdr,
 	return 0;
 }
 
+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);
+}
+
 static void xdr_set_next_page(struct xdr_stream *xdr)
 {
 	unsigned int newbase;
@@ -832,8 +983,7 @@ static void xdr_set_next_page(struct xdr_stream *xdr)
 	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->nwords << 2);
+	xdr_set_page(xdr, newbase, PAGE_SIZE);
 }
 
 static bool xdr_set_next_buffer(struct xdr_stream *xdr)
@@ -841,8 +991,7 @@ 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->nwords << 2);
+		xdr_set_page(xdr, 0, PAGE_SIZE);
 	}
 	return xdr->p != xdr->end;
 }
@@ -979,26 +1128,33 @@ out_overflow:
 }
 EXPORT_SYMBOL_GPL(xdr_inline_decode);
 
-static unsigned int xdr_align_pages(struct xdr_stream *xdr, unsigned int len)
+static void xdr_realign_pages(struct xdr_stream *xdr)
 {
 	struct xdr_buf *buf = xdr->buf;
-	struct kvec *iov;
-	unsigned int nwords = XDR_QUADLEN(len);
+	struct kvec *iov = buf->head;
 	unsigned int cur = xdr_stream_pos(xdr);
 	unsigned int copied, offset;
 
-	if (xdr->nwords == 0)
-		return 0;
-
 	/* Realign pages to current pointer position */
-	iov = buf->head;
 	if (iov->iov_len > cur) {
 		offset = iov->iov_len - cur;
 		copied = xdr_shrink_bufhead(buf, offset);
 		trace_rpc_xdr_alignment(xdr, offset, copied);
 		xdr->nwords = XDR_QUADLEN(buf->len - cur);
 	}
+}
 
+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;
+
+	if (xdr->nwords == 0)
+		return 0;
+
+	xdr_realign_pages(xdr);
 	if (nwords > xdr->nwords) {
 		nwords = xdr->nwords;
 		len = nwords << 2;
@@ -1057,6 +1213,79 @@ unsigned int xdr_read_pages(struct xdr_stream *xdr, unsigned int len)
 }
 EXPORT_SYMBOL_GPL(xdr_read_pages);
 
+uint64_t xdr_align_data(struct xdr_stream *xdr, uint64_t offset, uint32_t length)
+{
+	struct xdr_buf *buf = xdr->buf;
+	unsigned int from, bytes;
+	unsigned int shift = 0;
+
+	if ((offset + length) < offset ||
+	    (offset + length) > buf->page_len)
+		length = buf->page_len - offset;
+
+	xdr_realign_pages(xdr);
+	from = xdr_page_pos(xdr);
+	bytes = xdr->nwords << 2;
+	if (length < bytes)
+		bytes = length;
+
+	/* Move page data to the left */
+	if (from > offset) {
+		shift = min_t(unsigned int, bytes, buf->page_len - from);
+		_shift_data_left_pages(buf->pages,
+				       buf->page_base + offset,
+				       buf->page_base + from,
+				       shift);
+		bytes -= shift;
+
+		/* Move tail data into the pages, if necessary */
+		if (bytes > 0)
+			_shift_data_left_tail(buf, offset + shift, bytes);
+	}
+
+	xdr->nwords -= XDR_QUADLEN(length);
+	xdr_set_page(xdr, from + length, PAGE_SIZE);
+	return length;
+}
+EXPORT_SYMBOL_GPL(xdr_align_data);
+
+uint64_t xdr_expand_hole(struct xdr_stream *xdr, uint64_t offset, uint64_t 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;
+
+	xdr_realign_pages(xdr);
+	from = xdr_page_pos(xdr);
+	bytes = xdr->nwords << 2;
+
+	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;
+	}
+
+	/* 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, PAGE_SIZE);
+	return length;
+}
+EXPORT_SYMBOL_GPL(xdr_expand_hole);
+
 /**
  * xdr_enter_page - decode data from the XDR page
  * @xdr: pointer to xdr_stream struct