Re: [PATCH 6/7] block: Implement bdrv_{pread, pwrite, pwrite_zeroes}() using generated_co_wrapper

[Paolo Bonzini]

On 5/13/22 01:51, Alberto Faria wrote:
> Signed-off-by: Alberto Faria <afaria@redhat.com>
> ---
>   block/io.c               | 41 ----------------------------------------
>   include/block/block-io.h | 15 +++++++++------
>   2 files changed, 9 insertions(+), 47 deletions(-)
>
> diff --git a/block/io.c b/block/io.c
> index 78a289192e..ecd1c2a53c 100644
> --- a/block/io.c
> +++ b/block/io.c
> @@ -1061,14 +1061,6 @@ static int bdrv_check_request32(int64_t offset, int64_t 
> bytes,
>       return 0;
>   }
>   
> -int bdrv_pwrite_zeroes(BdrvChild *child, int64_t offset,
> -                       int64_t bytes, BdrvRequestFlags flags)
> -{
> -    IO_CODE();
> -    return bdrv_pwritev(child, offset, bytes, NULL,
> -                        BDRV_REQ_ZERO_WRITE | flags);
> -}

This is different from bdrv_co_pwrite_zeroes in that it does not clear 
BDRV_REQ_MAY_UNMAP; but that's a bugfix really.

It also doesn't call trace_bdrv_co_pwrite_zeroes, which is another bugfix.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>

>   /*
>    * Completely zero out a block device with the help of bdrv_pwrite_zeroes.
>    * The operation is sped up by checking the block status and only writing
> @@ -1111,39 +1103,6 @@ int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags 
> flags)
>       }
>   }
>   
> -/* See bdrv_pwrite() for the return codes */
> -int bdrv_pread(BdrvChild *child, int64_t offset, int64_t bytes, void *buf,
> -               BdrvRequestFlags flags)
> -{
> -    QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes);
> -    IO_CODE();
> -
> -    if (bytes < 0) {
> -        return -EINVAL;
> -    }
> -
> -    return bdrv_preadv(child, offset, bytes, &qiov, flags);
> -}
> -
> -/* Return no. of bytes on success or < 0 on error. Important errors are:
> -  -EIO         generic I/O error (may happen for all errors)
> -  -ENOMEDIUM   No media inserted.
> -  -EINVAL      Invalid offset or number of bytes
> -  -EACCES      Trying to write a read-only device
> -*/
> -int bdrv_pwrite(BdrvChild *child, int64_t offset, int64_t bytes,
> -                const void *buf, BdrvRequestFlags flags)
> -{
> -    QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, bytes);
> -    IO_CODE();
> -
> -    if (bytes < 0) {
> -        return -EINVAL;
> -    }
> -
> -    return bdrv_pwritev(child, offset, bytes, &qiov, flags);
> -}
> -
>   /*
>    * Writes to the file and ensures that no writes are reordered across this
>    * request (acts as a barrier)
> diff --git a/include/block/block-io.h b/include/block/block-io.h
> index 879221cebe..c81739ad16 100644
> --- a/include/block/block-io.h
> +++ b/include/block/block-io.h
> @@ -39,13 +39,16 @@
>    * to catch when they are accidentally called by the wrong API.
>    */
>   
> -int bdrv_pwrite_zeroes(BdrvChild *child, int64_t offset,
> -                       int64_t bytes, BdrvRequestFlags flags);
> +int generated_co_wrapper bdrv_pwrite_zeroes(BdrvChild *child, int64_t offset,
> +                                            int64_t bytes,
> +                                            BdrvRequestFlags flags);
>   int bdrv_make_zero(BdrvChild *child, BdrvRequestFlags flags);
> -int bdrv_pread(BdrvChild *child, int64_t offset, int64_t bytes, void *buf,
> -               BdrvRequestFlags flags);
> -int bdrv_pwrite(BdrvChild *child, int64_t offset, int64_t bytes,
> -                const void *buf, BdrvRequestFlags flags);
> +int generated_co_wrapper bdrv_pread(BdrvChild *child, int64_t offset,
> +                                    int64_t bytes, void *buf,
> +                                    BdrvRequestFlags flags);
> +int generated_co_wrapper bdrv_pwrite(BdrvChild *child, int64_t offset,
> +                                     int64_t bytes, const void *buf,
> +                                     BdrvRequestFlags flags);
>   int bdrv_pwrite_sync(BdrvChild *child, int64_t offset, int64_t bytes,
>                        const void *buf, BdrvRequestFlags flags);
>   /*