From: Anna Schumaker <[email protected]>
This patch adds the ability to "read a hole" into a set of XDR data
pages by taking the following steps:
1) Shift all data after the current xdr->p to the right, possibly into
the tail,
2) Zero the specified range, and
3) Update xdr->p to point beyond the hole.
Signed-off-by: Anna Schumaker <[email protected]>
---
include/linux/sunrpc/xdr.h | 1 +
net/sunrpc/xdr.c | 73 ++++++++++++++++++++++++++++++++++++++
2 files changed, 74 insertions(+)
diff --git a/include/linux/sunrpc/xdr.h b/include/linux/sunrpc/xdr.h
index 026edbd041d5..36a81c29542e 100644
--- a/include/linux/sunrpc/xdr.h
+++ b/include/linux/sunrpc/xdr.h
@@ -252,6 +252,7 @@ extern __be32 *xdr_inline_decode(struct xdr_stream *xdr, size_t nbytes);
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 uint64_t xdr_expand_hole(struct xdr_stream *, uint64_t, uint64_t);
/**
* xdr_stream_remaining - Return the number of bytes remaining in the stream
diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
index d8c9555c6f2b..24baf052e6e6 100644
--- a/net/sunrpc/xdr.c
+++ b/net/sunrpc/xdr.c
@@ -390,6 +390,42 @@ _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);
+
+ pgbase += zero;
+ if (pgbase == PAGE_SIZE) {
+ flush_dcache_page(*page);
+ pgbase = 0;
+ page++;
+ }
+
+ } while ((len -= zero) != 0);
+ flush_dcache_page(*page);
+}
+
/**
* xdr_shrink_bufhead
* @buf: xdr_buf
@@ -1141,6 +1177,43 @@ unsigned int xdr_read_pages(struct xdr_stream *xdr, unsigned int len)
}
EXPORT_SYMBOL_GPL(xdr_read_pages);
+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
--
2.28.0
On Mon, 2020-09-28 at 13:09 -0400, [email protected] wrote:
> From: Anna Schumaker <[email protected]>
>
> This patch adds the ability to "read a hole" into a set of XDR data
> pages by taking the following steps:
>
> 1) Shift all data after the current xdr->p to the right, possibly
> into
> the tail,
> 2) Zero the specified range, and
> 3) Update xdr->p to point beyond the hole.
>
> Signed-off-by: Anna Schumaker <[email protected]>
> ---
> include/linux/sunrpc/xdr.h | 1 +
> net/sunrpc/xdr.c | 73
> ++++++++++++++++++++++++++++++++++++++
> 2 files changed, 74 insertions(+)
>
> diff --git a/include/linux/sunrpc/xdr.h b/include/linux/sunrpc/xdr.h
> index 026edbd041d5..36a81c29542e 100644
> --- a/include/linux/sunrpc/xdr.h
> +++ b/include/linux/sunrpc/xdr.h
> @@ -252,6 +252,7 @@ extern __be32 *xdr_inline_decode(struct
> xdr_stream *xdr, size_t nbytes);
> 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 uint64_t xdr_expand_hole(struct xdr_stream *, uint64_t,
> uint64_t);
>
> /**
> * xdr_stream_remaining - Return the number of bytes remaining in
> the stream
> diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
> index d8c9555c6f2b..24baf052e6e6 100644
> --- a/net/sunrpc/xdr.c
> +++ b/net/sunrpc/xdr.c
> @@ -390,6 +390,42 @@ _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);
> +
> + pgbase += zero;
> + if (pgbase == PAGE_SIZE) {
Hmm.... Do we need to make this conditional? After all, if pgbase !=
PAGE_SIZE in this case, then zero == len, in which case we still want
to flush_dcache_page(*page) and then exit.
> + flush_dcache_page(*page);
> + pgbase = 0;
> + page++;
> + }
> +
> + } while ((len -= zero) != 0);
> + flush_dcache_page(*page);
> +}
> +
> /**
> * xdr_shrink_bufhead
> * @buf: xdr_buf
> @@ -1141,6 +1177,43 @@ unsigned int xdr_read_pages(struct xdr_stream
> *xdr, unsigned int len)
> }
> EXPORT_SYMBOL_GPL(xdr_read_pages);
>
> +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;
Hmm... Won't this mean that we also include the padding at the end of
the read buffer in 'bytes'?
> +
> + 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
--
Trond Myklebust
Linux NFS client maintainer, Hammerspace
[email protected]
Hi Trond,
On Thu, Oct 1, 2020 at 1:39 PM Trond Myklebust <[email protected]> wrote:
>
> On Mon, 2020-09-28 at 13:09 -0400, [email protected] wrote:
> > From: Anna Schumaker <[email protected]>
> >
> > This patch adds the ability to "read a hole" into a set of XDR data
> > pages by taking the following steps:
> >
> > 1) Shift all data after the current xdr->p to the right, possibly
> > into
> > the tail,
> > 2) Zero the specified range, and
> > 3) Update xdr->p to point beyond the hole.
> >
> > Signed-off-by: Anna Schumaker <[email protected]>
> > ---
> > include/linux/sunrpc/xdr.h | 1 +
> > net/sunrpc/xdr.c | 73
> > ++++++++++++++++++++++++++++++++++++++
> > 2 files changed, 74 insertions(+)
> >
> > diff --git a/include/linux/sunrpc/xdr.h b/include/linux/sunrpc/xdr.h
> > index 026edbd041d5..36a81c29542e 100644
> > --- a/include/linux/sunrpc/xdr.h
> > +++ b/include/linux/sunrpc/xdr.h
> > @@ -252,6 +252,7 @@ extern __be32 *xdr_inline_decode(struct
> > xdr_stream *xdr, size_t nbytes);
> > 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 uint64_t xdr_expand_hole(struct xdr_stream *, uint64_t,
> > uint64_t);
> >
> > /**
> > * xdr_stream_remaining - Return the number of bytes remaining in
> > the stream
> > diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
> > index d8c9555c6f2b..24baf052e6e6 100644
> > --- a/net/sunrpc/xdr.c
> > +++ b/net/sunrpc/xdr.c
> > @@ -390,6 +390,42 @@ _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);
> > +
> > + pgbase += zero;
> > + if (pgbase == PAGE_SIZE) {
>
> Hmm.... Do we need to make this conditional? After all, if pgbase !=
> PAGE_SIZE in this case, then zero == len, in which case we still want
> to flush_dcache_page(*page) and then exit.
I removed the condition, and everything works just the same. So I
guess it's not necessary. Good catch!
>
> > + flush_dcache_page(*page);
> > + pgbase = 0;
> > + page++;
> > + }
> > +
> > + } while ((len -= zero) != 0);
> > + flush_dcache_page(*page);
> > +}
> > +
> > /**
> > * xdr_shrink_bufhead
> > * @buf: xdr_buf
> > @@ -1141,6 +1177,43 @@ unsigned int xdr_read_pages(struct xdr_stream
> > *xdr, unsigned int len)
> > }
> > EXPORT_SYMBOL_GPL(xdr_read_pages);
> >
> > +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;
>
> Hmm... Won't this mean that we also include the padding at the end of
> the read buffer in 'bytes'?
I guess it would, assuming the server adds padding to the end of the
buffer. Should the server be adding padding here? Because it doesn't
the way I have it coded now (and RFC 7862 doesn't say anything about
padding at the end of a READ_PLUS reply).
Anna
>
> > +
> > + 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
> --
> Trond Myklebust
> Linux NFS client maintainer, Hammerspace
> [email protected]
>
>