}
EXPORT_SYMBOL_GPL(xdr_write_pages);
+static void xdr_set_iov(struct xdr_stream *xdr, struct kvec *iov,
+ __be32 *p, unsigned int len)
+{
+ if (len > iov->iov_len)
+ len = iov->iov_len;
+ if (p == NULL)
+ p = (__be32*)iov->iov_base;
+ xdr->p = p;
+ 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, NULL, 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, NULL, xdr->buf->len);
+ }
+ return xdr->p != xdr->end;
+}
+
/**
* xdr_init_decode - Initialize an xdr_stream for decoding data.
* @xdr: pointer to xdr_stream struct
*/
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;
+ if (buf->head[0].iov_len != 0)
+ xdr_set_iov(xdr, buf->head, p, buf->len);
+ else if (buf->page_len != 0)
+ xdr_set_page_base(xdr, 0, buf->len);
}
EXPORT_SYMBOL_GPL(xdr_init_decode);
-/**
- * xdr_inline_peek - Allow read-ahead in the XDR data stream
- * @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.
- */
-__be32 * xdr_inline_peek(struct xdr_stream *xdr, size_t nbytes)
+static __be32 * __xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes)
{
__be32 *p = xdr->p;
__be32 *q = p + XDR_QUADLEN(nbytes);
if (unlikely(q > xdr->end || q < p))
return NULL;
+ xdr->p = q;
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
*
*/
__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);
*/
void xdr_enter_page(struct xdr_stream *xdr, unsigned int len)
{
- char * kaddr = page_address(xdr->buf->pages[0]);
xdr_read_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);
+ xdr_set_page_base(xdr, 0, len);
}
EXPORT_SYMBOL_GPL(xdr_enter_page);
projects / mv-sheeva.git / blobdiff