* Disabling interrupts before block device request call
@ 2001-05-25 23:20 Alexandr Andreev
2001-05-25 22:01 ` Jens Axboe
0 siblings, 1 reply; 3+ messages in thread
From: Alexandr Andreev @ 2001-05-25 23:20 UTC (permalink / raw)
To: linux-kernel
Hi, list
In ll_rw_block.c, before calling block device specific request function
( i mean do_hd_request, do_ftl_request, ... ) the io_request_lock is
locking, and all interrupts are disabling. I know, that request handler
routine have to be atomic, but when we read data from a flash device (
for example ) we use a timeouts. Where do we have to enable timer
interrupts, or should we disable all interrupts?
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Disabling interrupts before block device request call
2001-05-25 23:20 Disabling interrupts before block device request call Alexandr Andreev
@ 2001-05-25 22:01 ` Jens Axboe
2001-05-28 19:24 ` Alexandr Andreev
0 siblings, 1 reply; 3+ messages in thread
From: Jens Axboe @ 2001-05-25 22:01 UTC (permalink / raw)
To: Alexandr Andreev; +Cc: linux-kernel
On Fri, May 25 2001, Alexandr Andreev wrote:
> Hi, list
> In ll_rw_block.c, before calling block device specific request function
> ( i mean do_hd_request, do_ftl_request, ... ) the io_request_lock is
> locking, and all interrupts are disabling. I know, that request handler
> routine have to be atomic, but when we read data from a flash device (
> for example ) we use a timeouts. Where do we have to enable timer
> interrupts, or should we disable all interrupts?
Even with dropping io_request_lock, it's not recommended to sleep inside
the request_fn. WIth plugging, you are basically preventing the other
plugged queues from being run until you return.
You could use a timer or similar to call you on a specified timeout
instead.
--
Jens Axboe
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Disabling interrupts before block device request call
2001-05-25 22:01 ` Jens Axboe
@ 2001-05-28 19:24 ` Alexandr Andreev
0 siblings, 0 replies; 3+ messages in thread
From: Alexandr Andreev @ 2001-05-28 19:24 UTC (permalink / raw)
To: Jens Axboe; +Cc: linux-kernel@vger.kernel.org
Jens Axboe wrote
>
>Even with dropping io_request_lock, it's not recommended to sleep inside
>the request_fn. WIth plugging, you are basically preventing the other
>plugged queues from being run until you return.
>
>You could use a timer or similar to call you on a specified timeout
>instead.
>
Does it mean, that if i need timer interrupts in my block device driver,
i need to do sti() instead of unlock io_request_lock? Is there any
common rule for device drivers in such case?
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2001-05-28 11:29 UTC | newest]
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2001-05-25 23:20 Disabling interrupts before block device request call Alexandr Andreev
2001-05-25 22:01 ` Jens Axboe
2001-05-28 19:24 ` Alexandr Andreev
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