Re: block io buffers (bio)

["Bahadir Balban" <bahadir.balban@xxxxxxxxx>]

On 5/3/07, Bahadir Balban <bahadir.balban@xxxxxxxxx> wrote:
> Hi,
>
> In bio_endio() I want to access the buffer whose transfer has been
> completed. How do I do safely do this?

Hi,

In fs/bio.c bio_endio() I have done:

/* Get buffer address */
void *buf = __bio_kmap_atomic(bio, bio->bi_idx, KM_USER0);
/* My action on the buffer */
flush_icache_range((unsigned long)buf, (unsigned long)(buf + bytes_done));
/* Give back buffer address */
__bio_kunmap_atomic(bio, KM_USER0);

in order to get access to the buffer. It seemed like
__bio_kmap_atomic() did what I want, but I am getting a kernel panic
with faulty virtual address 0xd0000000.

What am I missing? Would bio->bi_idx point me at the currently
completed buffer for example? Is it ok to do kmap_atomic in
bio_endio()?

Thanks,
Bahadir

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