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Re: [Qemu-devel] [PATCH 3/9] block: Track discard requests
From: |
Kevin Wolf |
Subject: |
Re: [Qemu-devel] [PATCH 3/9] block: Track discard requests |
Date: |
Wed, 28 Oct 2015 10:54:21 +0100 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
Am 26.10.2015 um 07:24 hat Fam Zheng geschrieben:
> Both bdrv_discard and bdrv_aio_discard will call into bdrv_co_discard,
> so add tracked_request_begin/end calls around the loop.
>
> Signed-off-by: Fam Zheng <address@hidden>
> ---
> block/io.c | 14 ++++++++++----
> 1 file changed, 10 insertions(+), 4 deletions(-)
>
> diff --git a/block/io.c b/block/io.c
> index 223c4e9..abb3aaa 100644
> --- a/block/io.c
> +++ b/block/io.c
> @@ -2415,7 +2415,8 @@ static void coroutine_fn bdrv_discard_co_entry(void
> *opaque)
> int coroutine_fn bdrv_co_discard(BlockDriverState *bs, int64_t sector_num,
> int nb_sectors)
> {
> - int max_discard, ret;
> + BdrvTrackedRequest req;
> + int max_discard, ret = 0;
>
> if (!bs->drv) {
> return -ENOMEDIUM;
> @@ -2437,6 +2438,8 @@ int coroutine_fn bdrv_co_discard(BlockDriverState *bs,
> int64_t sector_num,
> return 0;
> }
>
> + tracked_request_begin(&req, bs, sector_num, nb_sectors,
> + BDRV_TRACKED_DISCARD);
> bdrv_set_dirty(bs, sector_num, nb_sectors);
>
> max_discard = MIN_NON_ZERO(bs->bl.max_discard, BDRV_REQUEST_MAX_SECTORS);
> @@ -2470,20 +2473,23 @@ int coroutine_fn bdrv_co_discard(BlockDriverState
> *bs, int64_t sector_num,
> acb = bs->drv->bdrv_aio_discard(bs, sector_num, nb_sectors,
> bdrv_co_io_em_complete, &co);
> if (acb == NULL) {
> - return -EIO;
> + ret = -EIO;
> + goto out;
> } else {
> qemu_coroutine_yield();
> ret = co.ret;
> }
> }
> if (ret && ret != -ENOTSUP) {
> - return ret;
> + goto out;
> }
>
> sector_num += num;
> nb_sectors -= num;
> }
> - return 0;
> +out:
> + tracked_request_end(&req);
> + return ret;
> }
I would prefer an explicit ret = 0 before the out label because
otherwise you're relying on the previous value that has been set
somewhere in the loop. As far as I can tell, it's still correct, but it
makes it needlessly hard to tell whether success is 0 or >= 0.
Kevin
- [Qemu-devel] [PATCH 0/9] block: Fixes for bdrv_drain, Fam Zheng, 2015/10/26
- [Qemu-devel] [PATCH 1/9] block: Add more types for tracked request, Fam Zheng, 2015/10/26
- [Qemu-devel] [PATCH 2/9] block: Track flush requests, Fam Zheng, 2015/10/26
- [Qemu-devel] [PATCH 3/9] block: Track discard requests, Fam Zheng, 2015/10/26
- Re: [Qemu-devel] [PATCH 3/9] block: Track discard requests,
Kevin Wolf <=
- [Qemu-devel] [PATCH 4/9] iscsi: Emulate commands in iscsi_aio_ioctl as iscsi_ioctl, Fam Zheng, 2015/10/26
- [Qemu-devel] [PATCH 5/9] block: Add ioctl parameter fields to BlockRequest, Fam Zheng, 2015/10/26
- [Qemu-devel] [PATCH 6/9] block: Emulate bdrv_ioctl with bdrv_aio_ioctl and track both, Fam Zheng, 2015/10/26
- [Qemu-devel] [PATCH 7/9] block: Drop BlockDriver.bdrv_ioctl, Fam Zheng, 2015/10/26
- [Qemu-devel] [PATCH 8/9] block: Introduce BlockDriver.bdrv_drain callback, Fam Zheng, 2015/10/26