Re: [BUG] staging: android: ashmem: Deadlock during ashmem_shrink

[Robert Love]

On Mon, Apr 22, 2013 at 10:22 AM, Dan Carpenter
<dan.carpenter@xxxxxxxxxx> wrote:
> Read Al's email again:  https://lkml.org/lkml/2013/3/20/458
>
> I don't know much about VFS locking, but the ashmem locking seems
> pretty bogus to me.  Why can't multiple threads read() at the same
> time?

ashmem originally did not support read or write operations, just mmap,
which is all 99% of users want. The original concurrency model with
per-mapping ashmem_mutex's works fine there. It is only with the later
addition of read and write that locking becomes a cluster. If there
isn't an obvious way to refactor the locking, I'd suggest removing
read and write.

       Robert
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/