lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Fri, 25 Jul 2014 15:08:46 -0400
From:	"Martin K. Petersen" <martin.petersen@...cle.com>
To:	Christoph Hellwig <hch@....de>
Cc:	James Bottomley <James.Bottomley@...senPartnership.com>,
	linux-scsi@...r.kernel.org, Jens Axboe <axboe@...nel.dk>,
	Bart Van Assche <bvanassche@...ionio.com>,
	Mike Christie <michaelc@...wisc.edu>,
	"Martin K. Petersen" <martin.petersen@...cle.com>,
	Robert Elliott <Elliott@...com>, Webb Scales <webbnh@...com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 09/14] scsi: fix the {host,target,device}_blocked counter mess

>>>>> "Christoph" == Christoph Hellwig <hch@....de> writes:

Christoph> Seems like these counters are missing any sort of
Christoph> synchronization for updates, as a over 10 year old comment
Christoph> from me noted.  Fix this by using atomic counters, and while
Christoph> we're at it also make sure they are in the same cacheline as
Christoph> the _busy counters and not needlessly stored to in every I/O
Christoph> completion.

Christoph> With the new model the _busy counters can temporarily go
Christoph> negative, so all the readers are updated to check for > 0
Christoph> values.  Longer term every successful I/O completion will
Christoph> reset the counters to zero, so the temporarily negative
Christoph> values will not cause any harm.

Reviewed-by: Martin K. Petersen <martin.petersen@...cle.com>

-- 
Martin K. Petersen	Oracle Linux Engineering
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists