On Thu, 2009-12-24 at 12:03 +0100, Christoph Hellwig wrote:
> On Wed, Dec 23, 2009 at 03:22:25PM -0600, James Bottomley wrote:
> > xfs_buf.c includes what is essentially a hand rolled version of
> > blk_rq_map_kern(). In order to work properly with the vmalloc buffers
> > that xfs uses, this hand rolled routine must also implement the flushing
> > API for vmap/vmalloc areas.
> >
> > Signed-off-by: James Bottomley <James.Bottomley@xxxxxxx>
>
> Looks good except some minor style issues. Fix in the version below
> which also adds a helper to calculate the length of the vmap area
> instead of calculating it twice.
Sure ... I nearly did that ... but then there's a lot of stuff like that
repeated in the code.
I'll also add the optimisation that the invalidation is unnecessary in
the write case.
James
> ---
>
> From: James Bottomley <James.Bottomley@xxxxxxx>
> Subject: [PATCHv2 5/5] xfs: fix xfs to work with Virtually Indexed architectures
>
> xfs_buf.c includes what is essentially a hand rolled version of
> blk_rq_map_kern(). In order to work properly with the vmalloc buffers
> that xfs uses, this hand rolled routine must also implement the flushing
> API for vmap/vmalloc areas.
>
> Signed-off-by: James Bottomley <James.Bottomley@xxxxxxx>
>
> Index: linux-2.6/fs/xfs/linux-2.6/xfs_buf.c
> ===================================================================
> --- linux-2.6.orig/fs/xfs/linux-2.6/xfs_buf.c 2009-12-17 08:05:53.962275389 +0100
> +++ linux-2.6/fs/xfs/linux-2.6/xfs_buf.c 2009-12-24 11:59:02.031073134 +0100
> @@ -76,6 +76,27 @@ struct workqueue_struct *xfsconvertd_wor
> #define xfs_buf_deallocate(bp) \
> kmem_zone_free(xfs_buf_zone, (bp));
>
> +static inline int
> +xfs_buf_is_vmapped(
> + struct xfs_buf *bp)
> +{
> + /*
> + * Return true if the buffer is vmapped.
> + *
> + * The XBF_MAPPED flag is set if the buffer should be mapped, but the
> + * code is clever enough to know it doesn't have to map a single page,
> + * so the check has to be both for XBF_MAPPED and bp->b_page_count > 1.
> + */
> + return (bp->b_flags & XBF_MAPPED) && bp->b_page_count > 1;
> +}
> +
> +static inline int
> +xfs_buf_vmap_len(
> + struct xfs_buf *bp)
> +{
> + return (bp->b_page_count * PAGE_SIZE) - bp->b_offset;
> +}
> +
> /*
> * Page Region interfaces.
> *
> @@ -314,7 +335,7 @@ xfs_buf_free(
> if (bp->b_flags & (_XBF_PAGE_CACHE|_XBF_PAGES)) {
> uint i;
>
> - if ((bp->b_flags & XBF_MAPPED) && (bp->b_page_count > 1))
> + if (xfs_buf_is_vmapped(bp))
> free_address(bp->b_addr - bp->b_offset);
>
> for (i = 0; i < bp->b_page_count; i++) {
> @@ -1107,6 +1128,9 @@ xfs_buf_bio_end_io(
>
> xfs_buf_ioerror(bp, -error);
>
> + if (!error && xfs_buf_is_vmapped(bp))
> + invalidate_kernel_vmap_range(bp->b_addr, xfs_buf_vmap_len(bp));
> +
> do {
> struct page *page = bvec->bv_page;
>
> @@ -1216,6 +1240,10 @@ next_chunk:
>
> submit_io:
> if (likely(bio->bi_size)) {
> + if (xfs_buf_is_vmapped(bp)) {
> + flush_kernel_vmap_range(bp->b_addr,
> + xfs_buf_vmap_len(bp));
> + }
> submit_bio(rw, bio);
> if (size)
> goto next_chunk;
> --
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