Re: blkdev_issue_discard() hangs forever if the underlying storagedevice is removed

From: Lin Ming
Date: Mon Aug 29 2011 - 11:11:14 EST


On Mon, Aug 29, 2011 at 10:42 PM, Lukas Czerner <lczerner@xxxxxxxxxx> wrote:
> On Mon, 29 Aug 2011, Lin Ming wrote:
>
>> On Mon, Aug 29, 2011 at 7:56 PM, Lukas Czerner <lczerner@xxxxxxxxxx> wrote:
>> >
>> > Regarding the atomic operations I do not think that implicit memory
>> > barriers are needed here as atomic_dec_and_test() implies memory
>>
>> Which implicit memory barrier you are talking about?
>
> smp_mb() at both side of the operation as documented here in
> Documentation/memory-barriers.txt

Thanks for the info.

But I don't follow you ... why that implicit memory barriers are NOT needed?
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