On Sat, Jun 22, 2013 at 09:59:17AM +0200, Roger Pau Monne wrote:
> With the introduction of indirect segments we can receive requests
> with a number of segments bigger than the maximum number of allowed
> iovecs in a bios, so make sure that blkback doesn't try to allocate a
> bios with more iovecs than BIO_MAX_PAGES
Shouldn't we just gate the feature-indirect-descriptor value to
take this into account?
What happens if the nseg is > BIO_MAX_PAGES? Do we "lose" the request
for the remaining segments?
>
> Signed-off-by: Roger Pau Monné <roger....@citrix.com>
> Cc: Konrad Rzeszutek Wilk <konrad.w...@oracle.com>
> ---
> drivers/block/xen-blkback/blkback.c | 3 ++-
> 1 files changed, 2 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/block/xen-blkback/blkback.c
> b/drivers/block/xen-blkback/blkback.c
> index d622d86..b3897f5d 100644
> --- a/drivers/block/xen-blkback/blkback.c
> +++ b/drivers/block/xen-blkback/blkback.c
> @@ -1236,7 +1236,8 @@ static int dispatch_rw_block_io(struct xen_blkif *blkif,
> seg[i].nsec << 9,
> seg[i].offset) == 0)) {
>
> - bio = bio_alloc(GFP_KERNEL, nseg-i);
> + int nr_iovecs = min_t(int, (nseg-i), BIO_MAX_PAGES);
> + bio = bio_alloc(GFP_KERNEL, nr_iovecs);
> if (unlikely(bio == NULL))
> goto fail_put_bio;
>
> --
> 1.7.7.5 (Apple Git-26)
>
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