Am 24.04.2018 um 19:06 hat Eric Blake geschrieben: > On 04/24/2018 10:40 AM, Kevin Wolf wrote: > > Am 15.02.2018 um 20:28 hat Eric Blake geschrieben: > >> We are gradually moving away from sector-based interfaces, towards > >> byte-based. Add new sector-based aio callbacks for read and write, > >> to match the fact that bdrv_aio_pdiscard is already byte-based. > >> > >> Ideally, drivers should be converted to use coroutine callbacks > >> rather than aio; but that is not quite as trivial (if we do that > >> conversion, the null-aio driver will disappear), so for the > >> short term, converting the signature but keeping things with aio > >> is easier. Once all drivers are converted, the sector-based aio > >> callbacks will be removed. > >> > >> Signed-off-by: Eric Blake <[email protected]> > >> --- > >> include/block/block_int.h | 6 ++++++ > >> block/io.c | 37 +++++++++++++++++++++++++++---------- > >> 2 files changed, 33 insertions(+), 10 deletions(-) > >> > > >> +++ b/block/io.c > >> @@ -934,9 +934,11 @@ static int coroutine_fn > >> bdrv_driver_preadv(BlockDriverState *bs, > >> sector_num = offset >> BDRV_SECTOR_BITS; > >> nb_sectors = bytes >> BDRV_SECTOR_BITS; > >> > >> - assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0); > >> - assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0); > >> - assert((bytes >> BDRV_SECTOR_BITS) <= BDRV_REQUEST_MAX_SECTORS); > >> + if (!drv->bdrv_aio_preadv) { > >> + assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0); > >> + assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0); > >> + assert((bytes >> BDRV_SECTOR_BITS) <= BDRV_REQUEST_MAX_SECTORS); > >> + } > > > > Hm, this is kind of ugly. Previously, we handled everything byte-aligned > > in the first section, now we mix both in the second section. > > > > I can see that you do this so you don't have to duplicate the acb and > > coroutine yielding code below, but can we move things into the right > > place in the final patch at least? That is, calculate sector_num and > > nb_sectors only if all the byte-based interfaces weren't available. > > Yeah, that's easy enough to squash into patch 6: > > diff --git i/block/io.c w/block/io.c > index ba767612931..49fabe8eeb1 100644 > --- i/block/io.c > +++ w/block/io.c > @@ -924,16 +924,13 @@ static int coroutine_fn > bdrv_driver_preadv(BlockDriverState *bs, > return drv->bdrv_co_preadv(bs, offset, bytes, qiov, flags); > } > > - sector_num = offset >> BDRV_SECTOR_BITS; > - nb_sectors = bytes >> BDRV_SECTOR_BITS; > - > - if (!drv->bdrv_aio_preadv) { > - assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0); > - assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0); > - assert((bytes >> BDRV_SECTOR_BITS) <= BDRV_REQUEST_MAX_SECTORS); > - } > - > if (drv->bdrv_co_readv) { > + sector_num = offset >> BDRV_SECTOR_BITS; > + nb_sectors = bytes >> BDRV_SECTOR_BITS; > + > + assert((offset & (BDRV_SECTOR_SIZE - 1)) == 0); > + assert((bytes & (BDRV_SECTOR_SIZE - 1)) == 0); > + assert((bytes >> BDRV_SECTOR_BITS) <= BDRV_REQUEST_MAX_SECTORS); > return drv->bdrv_co_readv(bs, sector_num, nb_sectors, qiov); > } else { > BlockAIOCB *acb;
Ah, yes. I thought of moving the code in the else block, but this works, too. Maybe it's even a bit nicer. Kevin
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