diff options
| -rw-r--r-- | include/linux/sunrpc/xdr.h | 1 | ||||
| -rw-r--r-- | net/sunrpc/xdr.c | 121 |
2 files changed, 122 insertions, 0 deletions
diff --git a/include/linux/sunrpc/xdr.h b/include/linux/sunrpc/xdr.h index f9636d2a6d54..fe7ff7f5b584 100644 --- a/include/linux/sunrpc/xdr.h +++ b/include/linux/sunrpc/xdr.h @@ -250,6 +250,7 @@ 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_align_data(struct xdr_stream *, uint64_t, uint32_t); extern uint64_t xdr_expand_hole(struct xdr_stream *, uint64_t, uint64_t); /** diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c index 1052ccdb4e99..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 @@ -1128,6 +1213,42 @@ 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; |