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* [Qemu-devel] [PATCH] mirror: correct buf_size
@ 2015-05-14 10:07 Wen Congyang
  2015-05-14 10:20 ` Paolo Bonzini
  0 siblings, 1 reply; 2+ messages in thread
From: Wen Congyang @ 2015-05-14 10:07 UTC (permalink / raw)
  To: qemu-devl, Kevin Wolf, Jeff Cody, Fam Zheng

If buf_size % granularity is not 0, mirror_free_init() will
do dangerous things.

Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
---
 block/mirror.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/block/mirror.c b/block/mirror.c
index 58f391a..bb6bc27 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -686,6 +686,10 @@ static void mirror_start_job(BlockDriverState *bs, BlockDriverState *target,
     s->granularity = granularity;
     s->buf_size = MAX(buf_size, granularity);
 
+    if (s->buf_size % granularity != 0) {
+        s->buf_size = ROUND_UP(s->buf_size, granularity);
+    }
+
     s->dirty_bitmap = bdrv_create_dirty_bitmap(bs, granularity, NULL, errp);
     if (!s->dirty_bitmap) {
         return;
-- 
2.1.0

^ permalink raw reply related	[flat|nested] 2+ messages in thread

* Re: [Qemu-devel] [PATCH] mirror: correct buf_size
  2015-05-14 10:07 [Qemu-devel] [PATCH] mirror: correct buf_size Wen Congyang
@ 2015-05-14 10:20 ` Paolo Bonzini
  0 siblings, 0 replies; 2+ messages in thread
From: Paolo Bonzini @ 2015-05-14 10:20 UTC (permalink / raw)
  To: Wen Congyang, qemu-devl, Kevin Wolf, Jeff Cody, Fam Zheng



On 14/05/2015 12:07, Wen Congyang wrote:
> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
> ---
>  block/mirror.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/block/mirror.c b/block/mirror.c
> index 58f391a..bb6bc27 100644
> --- a/block/mirror.c
> +++ b/block/mirror.c
> @@ -686,6 +686,10 @@ static void mirror_start_job(BlockDriverState *bs, BlockDriverState *target,
>      s->granularity = granularity;
>      s->buf_size = MAX(buf_size, granularity);
>  
> +    if (s->buf_size % granularity != 0) {
> +        s->buf_size = ROUND_UP(s->buf_size, granularity);
> +    }
> +

Good catch!  But I think the "if" is not needed, and also this removes
the need for the s->buf_size assignment before.

The ROUND_UP is really the only thing that is needed.

Paolo

^ permalink raw reply	[flat|nested] 2+ messages in thread

end of thread, other threads:[~2015-05-14 10:21 UTC | newest]

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2015-05-14 10:07 [Qemu-devel] [PATCH] mirror: correct buf_size Wen Congyang
2015-05-14 10:20 ` Paolo Bonzini

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