On 11/20/2013 01:07 AM, Christoph Hellwig wrote:
>> Just stumbled on that too. You need one more, btw, for the sg failure
>> case:
>>
>>
>> diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
>> index 588479d58f52..6a680d4de7f1 100644
>> --- a/drivers/block/virtio_blk.c
>> +++ b/drivers/block/virtio_blk.c
>> @@ -199,15 +199,16 @@ static int virtio_queue_rq(struct blk_mq_hw_ctx *hctx,
>> struct request *req)
>>
>> spin_lock_irqsave(&vblk->vq_lock, flags);
>> if (__virtblk_add_req(vblk->vq, vbr, vbr->sg, num) < 0) {
>> + virtqueue_kick(vblk->vq);
>> spin_unlock_irqrestore(&vblk->vq_lock, flags);
>> blk_mq_stop_hw_queue(hctx);
>> - virtqueue_kick(vblk->vq);
>> return BLK_MQ_RQ_QUEUE_BUSY;
>> }
>> - spin_unlock_irqrestore(&vblk->vq_lock, flags);
>>
>> if (last)
>> virtqueue_kick(vblk->vq);
>> +
>> + spin_unlock_irqrestore(&vblk->vq_lock, flags);
>
> Note that virtqueue_kick can be split into a virtqueue_prepare_split
> that needs the lock, and a virtqueue_notify that doesn't, but it might
> not be nessecary to do that optimization right now.
Right, that would be easily doable. Seems it's in the realm of micro
optimizations, but worth doing next time it's touched.
> Btw, how much do I need to bribe you to send mails where I don't have
> step over 500 lines of dead quotes to find the actual patch?
Sorry, the next one was trimmed :-)
--
Jens Axboe
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