From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: "Reddy\, Sreekanth" <Sreekanth.Reddy@avagotech.com>
Cc: <jejb@kernel.org>, <JBottomley@Parallels.com>,
<linux-scsi@vger.kernel.org>, <Sathya.Prakash@avagotech.com>,
<Nagalakshmi.Nandigama@avagotech.com>,
<linux-kernel@vger.kernel.org>, <hch@infradead.org>,
<martin.petersen@oracle.com>
Subject: Re: [RESEND][PATCH 09/10][SCSI]mpt2sas: Added module parameter 'unblock_io' to unblock IO's during disk addition
Date: Thu, 21 Aug 2014 17:06:15 -0400 [thread overview]
Message-ID: <yq1oavdr1rs.fsf@sermon.lab.mkp.net> (raw)
In-Reply-To: <20140625103615.GA12959@avagotech.com> (Sreekanth Reddy's message of "Wed, 25 Jun 2014 16:06:15 +0530")
>>>>> "Sreekanth" == Reddy, Sreekanth <Sreekanth.Reddy@avagotech.com> writes:
Sreekanth> This is because, when driver receives DELAY_NOT_RESPONDING
Sreekanth> for a disk when it is undergoing addition in the SCSI Mid
Sreekanth> layer, the driver would block the I/O to that disk resulting
Sreekanth> in a deadlock. i.e the disk addition work couldn't be
Sreekanth> completed as it can't send any I/O to the disk as I/Os are
Sreekanth> blocked. Any device removal (TARGET_NOT_RESPONDING) or link
Sreekanth> update(RC_PHY_CHANGED) couldn't be processed as they are in
Sreekanth> the queue to get processed after disk addition.
Sreekanth> An module parameter 'unblock_io' is introduced which needs to
Sreekanth> be set to have this functionality enabled. By default this
Sreekanth> functionality is disabled.
This really sounds like a scenario you should be able to handle in
general (without special "don't-be-broken" module parameters).
Also, shouldn't your internal task management be able to deal with this?
Why does the sdev's state during probe affect your ability to make
forward progress?
--
Martin K. Petersen Oracle Linux Engineering
next prev parent reply other threads:[~2014-08-21 21:06 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-25 10:36 [RESEND][PATCH 09/10][SCSI]mpt2sas: Added module parameter 'unblock_io' to unblock IO's during disk addition Reddy, Sreekanth
2014-08-21 21:06 ` Martin K. Petersen [this message]
-- strict thread matches above, loose matches on Subject: below --
2014-08-25 19:35 Praveen Krishnamoorthy
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