[Qemu-devel] [PATCH] block: Simplify BDRV_BLOCK_RAW recursion

[Qemu-devel] [PATCH] block: Simplify BDRV_BLOCK_RAW recursion

[Eric Blake]

Since we are already in coroutine context during the body of
bdrv_co_get_block_status(), we can shave off a few layers of
wrappers when recursing to query the protocol when a format driver
returned BDRV_BLOCK_RAW.

Note that we are already using the correct recursion later on in
the same function, when probing whether the protocol layer is sparse
in order to find out if we can add BDRV_BLOCK_ZERO to an existing
BDRV_BLOCK_DATA|BDRV_BLOCK_OFFSET_VALID.

Signed-off-by: Eric Blake <eblake@redhat.com>
---
 block/io.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/block/io.c b/block/io.c
index 40bd94f..fdd7485 100644
--- a/block/io.c
+++ b/block/io.c
@@ -1784,8 +1784,8 @@ static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs,

     if (ret & BDRV_BLOCK_RAW) {
         assert(ret & BDRV_BLOCK_OFFSET_VALID);
-        ret = bdrv_get_block_status(*file, ret >> BDRV_SECTOR_BITS,
-                                    *pnum, pnum, file);
+        ret = bdrv_co_get_block_status(*file, ret >> BDRV_SECTOR_BITS,
+                                       *pnum, pnum, file);
         goto out;
     }

-- 
2.9.3

Re: [Qemu-devel] [PATCH] block: Simplify BDRV_BLOCK_RAW recursion

[Max Reitz]

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On 04.05.2017 19:37, Eric Blake wrote:
> Since we are already in coroutine context during the body of
> bdrv_co_get_block_status(), we can shave off a few layers of
> wrappers when recursing to query the protocol when a format driver
> returned BDRV_BLOCK_RAW.
> 
> Note that we are already using the correct recursion later on in
> the same function, when probing whether the protocol layer is sparse
> in order to find out if we can add BDRV_BLOCK_ZERO to an existing
> BDRV_BLOCK_DATA|BDRV_BLOCK_OFFSET_VALID.
> 
> Signed-off-by: Eric Blake <eblake@redhat.com>
> ---
>  block/io.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

Reviewed-by: Max Reitz <mreitz@redhat.com>


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Re: [Qemu-devel] [PATCH] block: Simplify BDRV_BLOCK_RAW recursion

[Fam Zheng]

On Thu, 05/04 12:37, Eric Blake wrote:
> Since we are already in coroutine context during the body of
> bdrv_co_get_block_status(), we can shave off a few layers of
> wrappers when recursing to query the protocol when a format driver
> returned BDRV_BLOCK_RAW.
> 
> Note that we are already using the correct recursion later on in
> the same function, when probing whether the protocol layer is sparse
> in order to find out if we can add BDRV_BLOCK_ZERO to an existing
> BDRV_BLOCK_DATA|BDRV_BLOCK_OFFSET_VALID.
> 
> Signed-off-by: Eric Blake <eblake@redhat.com>
> ---
>  block/io.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/block/io.c b/block/io.c
> index 40bd94f..fdd7485 100644
> --- a/block/io.c
> +++ b/block/io.c
> @@ -1784,8 +1784,8 @@ static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs,
> 
>      if (ret & BDRV_BLOCK_RAW) {
>          assert(ret & BDRV_BLOCK_OFFSET_VALID);
> -        ret = bdrv_get_block_status(*file, ret >> BDRV_SECTOR_BITS,
> -                                    *pnum, pnum, file);
> +        ret = bdrv_co_get_block_status(*file, ret >> BDRV_SECTOR_BITS,
> +                                       *pnum, pnum, file);
>          goto out;
>      }
> 
> -- 
> 2.9.3
> 
> 

Reviewed-by: Fam Zheng <famz@redhat.com>

Re: [Qemu-devel] [PATCH] block: Simplify BDRV_BLOCK_RAW recursion

[Stefan Hajnoczi]

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On Thu, May 04, 2017 at 12:37:45PM -0500, Eric Blake wrote:
> Since we are already in coroutine context during the body of
> bdrv_co_get_block_status(), we can shave off a few layers of
> wrappers when recursing to query the protocol when a format driver
> returned BDRV_BLOCK_RAW.
> 
> Note that we are already using the correct recursion later on in
> the same function, when probing whether the protocol layer is sparse
> in order to find out if we can add BDRV_BLOCK_ZERO to an existing
> BDRV_BLOCK_DATA|BDRV_BLOCK_OFFSET_VALID.
> 
> Signed-off-by: Eric Blake <eblake@redhat.com>
> ---
>  block/io.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

Thanks, applied to my block tree:
https://github.com/stefanha/qemu/commits/block

Stefan

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