On 02/03/2017 02:31 PM, Christoph Hellwig wrote:
>> -            if (sg_res_in_use(sfp)) {
>> +            mutex_lock(&sfp->f_mutex);
>> +            if (sfp->res_in_use) {
>> +                    mutex_unlock(&sfp->f_mutex);
>>                      sg_remove_request(sfp, srp);
>>                      return -EBUSY;  /* reserve buffer already being used */
>>              }
>> +            mutex_unlock(&sfp->f_mutex);
> 
> Holding a mutex over a the check of a single scalar doesn't make sense.
> 
It's adds a synchronisation point, doesn't it?

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Teamlead Storage & Networking
h...@suse.de                                   +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
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