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Re: [Qemu-devel] [PULL 10/11] block: Fix bdrv_co_flush early return
From: |
Peter Maydell |
Subject: |
Re: [Qemu-devel] [PULL 10/11] block: Fix bdrv_co_flush early return |
Date: |
Tue, 25 Apr 2017 16:00:33 +0100 |
On 11 April 2017 at 13:26, Fam Zheng <address@hidden> wrote:
> bdrv_inc_in_flight and bdrv_dec_in_flight are mandatory for
> BDRV_POLL_WHILE to work, even for the shortcut case where flush is
> unnecessary. Move the if block to below bdrv_dec_in_flight, and BTW fix
> the variable declaration position.
>
> Signed-off-by: Fam Zheng <address@hidden>
> Acked-by: Stefan Hajnoczi <address@hidden>
> Reviewed-by: Kevin Wolf <address@hidden>
> Reviewed-by: Paolo Bonzini <address@hidden>
> ---
> block/io.c | 16 +++++++++-------
> 1 file changed, 9 insertions(+), 7 deletions(-)
>
> diff --git a/block/io.c b/block/io.c
> index 00e45ca..bae6947 100644
> --- a/block/io.c
> +++ b/block/io.c
> @@ -2278,16 +2278,17 @@ static void coroutine_fn bdrv_flush_co_entry(void
> *opaque)
>
> int coroutine_fn bdrv_co_flush(BlockDriverState *bs)
> {
> - int ret;
> -
> - if (!bs || !bdrv_is_inserted(bs) || bdrv_is_read_only(bs) ||
> - bdrv_is_sg(bs)) {
> - return 0;
> - }
> + int current_gen;
> + int ret = 0;
>
> bdrv_inc_in_flight(bs);
>
> - int current_gen = bs->write_gen;
> + if (!bs || !bdrv_is_inserted(bs) || bdrv_is_read_only(bs) ||
> + bdrv_is_sg(bs)) {
> + goto early_exit;
> + }
Coverity points out that there's a problem here -- we call
bdrv_inc_in_flight(bs), which assumes bs is not NULL, before
we do the test for whether bs is NULL.
Presumably the NULL check needs to be pulled up earlier in
the function?
thanks
-- PMM
- [Qemu-devel] [PULL 02/11] block: Quiesce old aio context during bdrv_set_aio_context, (continued)
- [Qemu-devel] [PULL 02/11] block: Quiesce old aio context during bdrv_set_aio_context, Fam Zheng, 2017/04/11
- [Qemu-devel] [PULL 03/11] tests/block-job-txn: Don't start block job before adding to txn, Fam Zheng, 2017/04/11
- [Qemu-devel] [PULL 04/11] coroutine: Extract qemu_aio_coroutine_enter, Fam Zheng, 2017/04/11
- [Qemu-devel] [PULL 05/11] async: Introduce aio_co_enter, Fam Zheng, 2017/04/11
- [Qemu-devel] [PULL 06/11] block: Introduce bdrv_coroutine_enter, Fam Zheng, 2017/04/11
- [Qemu-devel] [PULL 07/11] blockjob: Use bdrv_coroutine_enter to start coroutine, Fam Zheng, 2017/04/11
- [Qemu-devel] [PULL 08/11] qemu-io-cmds: Use bdrv_coroutine_enter, Fam Zheng, 2017/04/11
- [Qemu-devel] [PULL 09/11] block: Use bdrv_coroutine_enter to start I/O coroutines, Fam Zheng, 2017/04/11
- [Qemu-devel] [PULL 11/11] sheepdog: Use bdrv_coroutine_enter before BDRV_POLL_WHILE, Fam Zheng, 2017/04/11
- [Qemu-devel] [PULL 10/11] block: Fix bdrv_co_flush early return, Fam Zheng, 2017/04/11
- Re: [Qemu-devel] [PULL 10/11] block: Fix bdrv_co_flush early return,
Peter Maydell <=
- Re: [Qemu-devel] [PULL 00/11] Block patches for 2.9-rc4, Peter Maydell, 2017/04/11