[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH v8 19/21] vpc: Switch to .bdrv_co_block_status()
From: |
Kevin Wolf |
Subject: |
Re: [Qemu-devel] [PATCH v8 19/21] vpc: Switch to .bdrv_co_block_status() |
Date: |
Wed, 14 Feb 2018 14:08:48 +0100 |
User-agent: |
Mutt/1.9.1 (2017-09-22) |
Am 13.02.2018 um 21:26 hat Eric Blake geschrieben:
> We are gradually moving away from sector-based interfaces, towards
> byte-based. Update the vpc driver accordingly.
>
> Signed-off-by: Eric Blake <address@hidden>
> Reviewed-by: Vladimir Sementsov-Ogievskiy <address@hidden>
> Reviewed-by: Fam Zheng <address@hidden>
>
> ---
> v7: tweak commit message and type of 'n' [Fam]
> v6: no change
> v5: fix incorrect rounding in 'map' and bad loop condition [Vladimir]
> v4: rebase to interface tweak
> v3: rebase to master
> v2: drop get_sector_offset() [Kevin], rebase to mapping flag
> ---
> block/vpc.c | 45 +++++++++++++++++++++++----------------------
> 1 file changed, 23 insertions(+), 22 deletions(-)
>
> diff --git a/block/vpc.c b/block/vpc.c
> index cfa5144e867..fba4492fd7b 100644
> --- a/block/vpc.c
> +++ b/block/vpc.c
> @@ -706,53 +706,54 @@ fail:
> return ret;
> }
>
> -static int64_t coroutine_fn vpc_co_get_block_status(BlockDriverState *bs,
> - int64_t sector_num, int nb_sectors, int *pnum, BlockDriverState
> **file)
> +static int coroutine_fn vpc_co_block_status(BlockDriverState *bs,
> + bool want_zero,
> + int64_t offset, int64_t bytes,
> + int64_t *pnum, int64_t *map,
> + BlockDriverState **file)
> {
> BDRVVPCState *s = bs->opaque;
> VHDFooter *footer = (VHDFooter*) s->footer_buf;
> - int64_t start, offset;
> + int64_t image_offset;
> bool allocated;
> - int64_t ret;
> - int n;
> + int ret;
> + int64_t n;
>
> if (be32_to_cpu(footer->type) == VHD_FIXED) {
> - *pnum = nb_sectors;
> + *pnum = bytes;
> + *map = offset;
> *file = bs->file->bs;
> - return BDRV_BLOCK_RAW | BDRV_BLOCK_OFFSET_VALID |
> - (sector_num << BDRV_SECTOR_BITS);
> + return BDRV_BLOCK_RAW | BDRV_BLOCK_OFFSET_VALID;
> }
>
> qemu_co_mutex_lock(&s->lock);
>
> - offset = get_image_offset(bs, sector_num << BDRV_SECTOR_BITS, false,
> NULL);
> - start = offset;
> - allocated = (offset != -1);
> + image_offset = get_image_offset(bs, offset, false, NULL);
> + allocated = (image_offset != -1);
> *pnum = 0;
> ret = 0;
>
> do {
> /* All sectors in a block are contiguous (without using the bitmap)
> */
> - n = ROUND_UP(sector_num + 1, s->block_size / BDRV_SECTOR_SIZE)
> - - sector_num;
> - n = MIN(n, nb_sectors);
> + n = ROUND_UP(offset + 1, s->block_size) - offset;
> + n = MIN(n, bytes);
>
> *pnum += n;
> - sector_num += n;
> - nb_sectors -= n;
> + offset += n;
> + bytes -= n;
> /* *pnum can't be greater than one block for allocated
> * sectors since there is always a bitmap in between. */
> if (allocated) {
> *file = bs->file->bs;
> - ret = BDRV_BLOCK_DATA | BDRV_BLOCK_OFFSET_VALID | start;
> + *map = image_offset;
This does work, but only because the loop isn't actually looping for
allocated == true. In the old code, it was obvious that start was
assigned only once and never changed during the loop, but image_offset
changes in each loop iteration.
It would probably be cleaner and more obviously correct to move the
assignment of *map to before the loop.
Kevin
- [Qemu-devel] [PATCH v8 03/21] block: Switch passthrough drivers to .bdrv_co_block_status(), (continued)
- [Qemu-devel] [PATCH v8 03/21] block: Switch passthrough drivers to .bdrv_co_block_status(), Eric Blake, 2018/02/13
- [Qemu-devel] [PATCH v8 12/21] qcow2: Switch to .bdrv_co_block_status(), Eric Blake, 2018/02/13
- [Qemu-devel] [PATCH v8 13/21] qed: Switch to .bdrv_co_block_status(), Eric Blake, 2018/02/13
- [Qemu-devel] [PATCH v8 15/21] sheepdog: Switch to .bdrv_co_block_status(), Eric Blake, 2018/02/13
- [Qemu-devel] [PATCH v8 17/21] vdi: Switch to .bdrv_co_block_status(), Eric Blake, 2018/02/13
- [Qemu-devel] [PATCH v8 20/21] vvfat: Switch to .bdrv_co_block_status(), Eric Blake, 2018/02/13
- [Qemu-devel] [PATCH v8 19/21] vpc: Switch to .bdrv_co_block_status(), Eric Blake, 2018/02/13
- Re: [Qemu-devel] [PATCH v8 19/21] vpc: Switch to .bdrv_co_block_status(),
Kevin Wolf <=
- [Qemu-devel] [PATCH v8 21/21] block: Drop unused .bdrv_co_get_block_status(), Eric Blake, 2018/02/13
- [Qemu-devel] [PATCH v8 16/21] vdi: Avoid bitrot of debugging code, Eric Blake, 2018/02/13
- [Qemu-devel] [PATCH v8 18/21] vmdk: Switch to .bdrv_co_block_status(), Eric Blake, 2018/02/13
- Re: [Qemu-devel] [PATCH v8 00/21] add byte-based block_status driver callbacks, Kevin Wolf, 2018/02/14