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Re: [PATCH] block: use the request length for iov alignment
From: |
Keith Busch |
Subject: |
Re: [PATCH] block: use the request length for iov alignment |
Date: |
Tue, 13 Sep 2022 15:12:26 +0100 |
On Thu, Sep 08, 2022 at 09:45:26AM -0700, Keith Busch wrote:
> From: Keith Busch <kbusch@kernel.org>
>
> An iov length needs to be aligned to the logical block size, which may
> be larger than the memory alignment.
[cc'ing some other interested folks]
Any thoughts on this patch? It is fixing an observed IO error when running
virtio-blk with the default 512b logical block size backed by a drive formatted
with 4k logical block.
> ---
> block/io.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/block/io.c b/block/io.c
> index 0a8cbefe86..296d4b49a7 100644
> --- a/block/io.c
> +++ b/block/io.c
> @@ -3243,13 +3243,14 @@ bool bdrv_qiov_is_aligned(BlockDriverState *bs,
> QEMUIOVector *qiov)
> {
> int i;
> size_t alignment = bdrv_min_mem_align(bs);
> + size_t len = bs->bl.request_alignment;
> IO_CODE();
>
> for (i = 0; i < qiov->niov; i++) {
> if ((uintptr_t) qiov->iov[i].iov_base % alignment) {
> return false;
> }
> - if (qiov->iov[i].iov_len % alignment) {
> + if (qiov->iov[i].iov_len % len) {
> return false;
> }
> }
> --
> 2.30.2
>