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Re: [PATCH 1/3] block: eliminate BDRV_REQ_NO_SERIALISING
From: |
Kevin Wolf |
Subject: |
Re: [PATCH 1/3] block: eliminate BDRV_REQ_NO_SERIALISING |
Date: |
Wed, 18 Dec 2019 17:37:54 +0100 |
User-agent: |
Mutt/1.12.1 (2019-06-15) |
[ Fixing the qemu-block address ]
Am 18.12.2019 um 14:17 hat Paolo Bonzini geschrieben:
> It is unused since commit 00e30f0 ("block/backup: use backup-top instead
> of write notifiers", 2019-10-01), drop it to simplify the code.
>
> While at it, drop redundant assertions on flags.
>
> Signed-off-by: Paolo Bonzini <address@hidden>
> ---
> block/io.c | 18 ++++--------------
> include/block/block.h | 12 ------------
> 2 files changed, 4 insertions(+), 26 deletions(-)
>
> diff --git a/block/io.c b/block/io.c
> index f75777f..b3a67fe 100644
> --- a/block/io.c
> +++ b/block/io.c
> @@ -1445,8 +1445,7 @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild
> *child,
> * potential fallback support, if we ever implement any read flags
> * to pass through to drivers. For now, there aren't any
> * passthrough flags. */
> - assert(!(flags & ~(BDRV_REQ_NO_SERIALISING | BDRV_REQ_COPY_ON_READ |
> - BDRV_REQ_PREFETCH)));
> + assert(!(flags & ~(BDRV_REQ_COPY_ON_READ | BDRV_REQ_PREFETCH)));
>
> /* Handle Copy on Read and associated serialisation */
> if (flags & BDRV_REQ_COPY_ON_READ) {
> @@ -1458,12 +1457,7 @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild
> *child,
> bdrv_mark_request_serialising(req, bdrv_get_cluster_size(bs));
> }
>
> - /* BDRV_REQ_SERIALISING is only for write operation */
> - assert(!(flags & BDRV_REQ_SERIALISING));
I think we shoud still keep this assertion as long as read requests
don't mark themselves as serialising when BDRV_REQ_SERIALISING is given.
Otherwise, someone might add the flag to a read request and will later
be surprised that it didn't work.
> - if (!(flags & BDRV_REQ_NO_SERIALISING)) {
> - bdrv_wait_serialising_requests(req);
> - }
> + bdrv_wait_serialising_requests(req);
>
> if (flags & BDRV_REQ_COPY_ON_READ) {
> int64_t pnum;
> @@ -1711,7 +1705,7 @@ int coroutine_fn bdrv_co_preadv_part(BdrvChild *child,
> bdrv_inc_in_flight(bs);
>
> /* Don't do copy-on-read if we read data before write operation */
> - if (atomic_read(&bs->copy_on_read) && !(flags &
> BDRV_REQ_NO_SERIALISING)) {
> + if (atomic_read(&bs->copy_on_read)) {
The comment wants an update, too (or maybe a removal).
> flags |= BDRV_REQ_COPY_ON_READ;
> }
>
> @@ -1852,8 +1846,6 @@ bdrv_co_write_req_prepare(BdrvChild *child, int64_t
> offset, uint64_t bytes,
> return -EPERM;
> }
>
> - /* BDRV_REQ_NO_SERIALISING is only for read operation */
> - assert(!(flags & BDRV_REQ_NO_SERIALISING));
> assert(!(bs->open_flags & BDRV_O_INACTIVE));
> assert((bs->open_flags & BDRV_O_NO_IO) == 0);
> assert(!(flags & ~BDRV_REQ_MASK));
> @@ -3222,9 +3214,7 @@ static int coroutine_fn bdrv_co_copy_range_internal(
>
> /* BDRV_REQ_SERIALISING is only for write operation */
> assert(!(read_flags & BDRV_REQ_SERIALISING));
Here you kept the assertion, so apart from making sense anyway, it would
also be more consistent to keep it above, too. :-)
> - if (!(read_flags & BDRV_REQ_NO_SERIALISING)) {
> - bdrv_wait_serialising_requests(&req);
> - }
> + bdrv_wait_serialising_requests(&req);
>
> ret = src->bs->drv->bdrv_co_copy_range_from(src->bs,
Kevin