On Tue, Jul 24 2001, Peter T. Breuer wrote:
> What's the semaphore field in requests for? Are driver writers supposed
> to be using it?
Drivers can use it if they want completion to be signalled for a request
(see end_that_request_last). However, see 2.4.7 where it's not ->waiting
and the interface changed.
> The block driver is largely in userspace. All the kernel half does
> is transfer requests to a local queue (with the io lock still held, of
> course). The userspace daemon cycles continously doing ioctls that
> copy the requests (bh by bh) into userspace, where its treated via
> some networking calls, then return an ack via another ioctl.
>
> The drivers local queue is protected by a semaphore. The thing that
> puzzles me is that the bug shows only when copying to a disk device,
> not to /dev/null, through userspace! Is it that the lifetime of a
> request is much longer than expected?
Well all the explanations in the world doesn't help much -- show the
code.
-- Jens Axboe- 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/
This archive was generated by hypermail 2b29 : Tue Jul 31 2001 - 21:00:15 EST