[PATCH]:drivers/md/raid10.c: r10buf_pool_alloc(): Set bi_vcnt for the new bio.

[PATCH]:drivers/md/raid10.c: r10buf_pool_alloc(): Set bi_vcnt for the new bio.

[Muthu Kumar]

Hi Neil,
raid10.c: r10buf_pool_alloc() - doesn't set the bi_vcnt for the newly
allocated bio. Setting it to RESYNC_PAGES for successful case.

BTW, why are we not using bio_add_page() here to add the page to bio?

Signed-off-by: Muthukumar R <muthur@gmail.com>

------
 drivers/md/raid10.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
------
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index 6e84668..8504c5b 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -129,6 +129,7 @@ static void * r10buf_pool_alloc(gfp_t gfp_flags, void *data)

                        bio->bi_io_vec[i].bv_page = page;
                }
+               bio->bi_vcnt = RESYNC_PAGES;
        }

        return r10_bio;

Re: [PATCH]:drivers/md/raid10.c: r10buf_pool_alloc(): Set bi_vcnt for the new bio.

[NeilBrown]

On Tue, 12 Jul 2011 17:50:32 -0700 Muthu Kumar <muthu.lkml@gmail.com> wrote:

> Hi Neil,
> raid10.c: r10buf_pool_alloc() - doesn't set the bi_vcnt for the newly
> allocated bio. Setting it to RESYNC_PAGES for successful case.

What would be the point of doing that?  When an r10buf allocated in
sync_request(), one of the first things done to it is to initialise it
including setting bi_vcnt to 0.

> 
> BTW, why are we not using bio_add_page() here to add the page to bio?

How would that be useful?  We don't know what the underlying device is at
this point, and the point of bio_add_page is to make sure the device can
handle the extra page.

We do call bio_add_page at the appropriate time in sync_request().

So - not applied.

Thanks,
NeilBrown


> 
> Signed-off-by: Muthukumar R <muthur@gmail.com>
> 
> ------
>  drivers/md/raid10.c |    1 +
>  1 files changed, 1 insertions(+), 0 deletions(-)
> ------
> diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
> index 6e84668..8504c5b 100644
> --- a/drivers/md/raid10.c
> +++ b/drivers/md/raid10.c
> @@ -129,6 +129,7 @@ static void * r10buf_pool_alloc(gfp_t gfp_flags, void *data)
> 
>                         bio->bi_io_vec[i].bv_page = page;
>                 }
> +               bio->bi_vcnt = RESYNC_PAGES;
>         }
> 
>         return r10_bio;
> --
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Re: [PATCH]:drivers/md/raid10.c: r10buf_pool_alloc(): Set bi_vcnt for the new bio.

[Muthu Kumar]

Hi Neil,

>>
>> BTW, why are we not using bio_add_page() here to add the page to bio?
>
> How would that be useful?  We don't know what the underlying device is at
> this point, and the point of bio_add_page is to make sure the device can
> handle the extra page.
>
> We do call bio_add_page at the appropriate time in sync_request().

Yes. Thanks for the explanation.

Regards,
Muthu

>
> So - not applied.
>
> Thanks,
> NeilBrown
>
>
>>
>> Signed-off-by: Muthukumar R <muthur@gmail.com>
>>
>> ------
>>  drivers/md/raid10.c |    1 +
>>  1 files changed, 1 insertions(+), 0 deletions(-)
>> ------
>> diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
>> index 6e84668..8504c5b 100644
>> --- a/drivers/md/raid10.c
>> +++ b/drivers/md/raid10.c
>> @@ -129,6 +129,7 @@ static void * r10buf_pool_alloc(gfp_t gfp_flags, void *data)
>>
>>                         bio->bi_io_vec[i].bv_page = page;
>>                 }
>> +               bio->bi_vcnt = RESYNC_PAGES;
>>         }
>>
>>         return r10_bio;
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>> Please read the FAQ at  http://www.tux.org/lkml/
>
>