Re: [Qemu-devel] [PATCH V3 5/6] ide: enable buffered requests for ATAPI devices

[Peter Lieven <pl@kamp.de>]

Am 12.11.2015 um 12:25 schrieb Fam Zheng:
> On Fri, 11/06 09:42, Peter Lieven wrote:
>> Signed-off-by: Peter Lieven <pl@kamp.de>
>> ---
>>   hw/ide/atapi.c | 10 +++++-----
>>   1 file changed, 5 insertions(+), 5 deletions(-)
>>
>> diff --git a/hw/ide/atapi.c b/hw/ide/atapi.c
>> index 29fd131..2f6d018 100644
>> --- a/hw/ide/atapi.c
>> +++ b/hw/ide/atapi.c
>> @@ -190,8 +190,8 @@ static int cd_read_sector(IDEState *s, void *buf)
>>       block_acct_start(blk_get_stats(s->blk), &s->acct,
>>                        4 * BDRV_SECTOR_SIZE, BLOCK_ACCT_READ);
>>   
>> -    blk_aio_readv(s->blk, (int64_t)s->lba << 2, &s->qiov, 4,
>> -                  cd_read_sector_cb, s);
>> +    ide_buffered_readv(s, (int64_t)s->lba << 2, &s->qiov, 4,
>> +                       cd_read_sector_cb, s);
>>   
>>       s->status |= BUSY_STAT;
>>       return 0;
>> @@ -424,9 +424,9 @@ static void ide_atapi_cmd_read_dma_cb(void *opaque, int ret)
>>       s->bus->dma->iov.iov_len = n * 4 * 512;
>>       qemu_iovec_init_external(&s->bus->dma->qiov, &s->bus->dma->iov, 1);
>>   
>> -    s->bus->dma->aiocb = blk_aio_readv(s->blk, (int64_t)s->lba << 2,
>> -                                       &s->bus->dma->qiov, n * 4,
>> -                                       ide_atapi_cmd_read_dma_cb, s);
>> +    s->bus->dma->aiocb = ide_buffered_readv(s, (int64_t)s->lba << 2,
>> +                                            &s->bus->dma->qiov, n * 4,
>> +                                            ide_atapi_cmd_read_dma_cb, s);
> IIRC the dma aiocb are still going to be drained in bmdma_cmd_writeb, so why do
> we need the bounce buffer?

They dont ;-)

If s->bus->dma->aiocb is a buffered Request, it will be set to NULL in this
call:

req->original_cb(req->original_opaque, -ECANCELED);

Peter