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From: "Matthew R. Ochs" <mrochs@linux.vnet.ibm.com>
To: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Cc: linux-scsi@vger.kernel.org,
	James Bottomley <jejb@linux.vnet.ibm.com>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	"Manoj N. Kumar" <manoj@linux.vnet.ibm.com>,
	Brian King <brking@linux.vnet.ibm.com>,
	linuxppc-dev@lists.ozlabs.org, Ian Munsie <imunsie@au1.ibm.com>,
	Andrew Donnellan <andrew.donnellan@au1.ibm.com>,
	Frederic Barrat <fbarrat@linux.vnet.ibm.com>,
	Christophe Lombard <clombard@linux.vnet.ibm.com>
Subject: Re: [PATCH 2/6] cxlflash: Remove the device cleanly in the system shutdown path
Date: Wed, 7 Sep 2016 18:46:35 -0500	[thread overview]
Message-ID: <64F2AAD6-ADF0-4940-A4F1-7541177639EC@linux.vnet.ibm.com> (raw)
In-Reply-To: <1472848756-64998-1-git-send-email-ukrishn@linux.vnet.ibm.com>

> On Sep 2, 2016, at 3:39 PM, Uma Krishnan <ukrishn@linux.vnet.ibm.com> wrote:
> 
> Commit 704c4b0ddc03 ("cxlflash: Shutdown notify support for CXL Flash
> cards") was recently introduced to notify the AFU when a system is going
> down. Due to the position of the cxlflash driver in the device stack,
> cxlflash devices are _always_ removed during a reboot/shutdown. This can
> lead to a crash if the cxlflash shutdown hook is invoked _after_ the
> shutdown hook for the owning virtual PHB. Furthermore, the current
> implementation of shutdown/remove hooks for cxlflash are not tolerant to
> being invoked when the device is not enabled. This can also lead to a
> crash in situations where the remove hook is invoked after the device has
> been removed via the vPHBs shutdown hook. An example of this scenario
> would be an EEH reset failure while a reboot/shutdown is in progress.
> 
> To solve both problems, the shutdown hook for cxlflash is updated to
> simply remove the device. This path already includes the AFU notification
> and thus this solution will continue to perform the original intent. At
> the same time, the remove hook is updated to protect against being
> called when the device is not enabled.
> 
> Fixes: 704c4b0ddc03 ("cxlflash: Shutdown notify support for CXL Flash
> cards")
> Signed-off-by: Uma Krishna <ukrishn@linux.vnet.ibm.com>

Acked-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>


WARNING: multiple messages have this Message-ID (diff)
From: "Matthew R. Ochs" <mrochs@linux.vnet.ibm.com>
To: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Cc: linux-scsi@vger.kernel.org,
	James Bottomley <jejb@linux.vnet.ibm.com>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	"Manoj N. Kumar" <manoj@linux.vnet.ibm.com>,
	Brian King <brking@linux.vnet.ibm.com>,
	linuxppc-dev@lists.ozlabs.org, Ian Munsie <imunsie@au1.ibm.com>,
	Andrew Donnellan <andrew.donnellan@au1.ibm.com>,
	Frederic Barrat <fbarrat@linux.vnet.ibm.com>,
	Christophe Lombard <clombard@linux.vnet.ibm.com>
Subject: Re: [PATCH 2/6] cxlflash: Remove the device cleanly in the system shutdown path
Date: Wed, 7 Sep 2016 18:46:35 -0500	[thread overview]
Message-ID: <64F2AAD6-ADF0-4940-A4F1-7541177639EC@linux.vnet.ibm.com> (raw)
In-Reply-To: <1472848756-64998-1-git-send-email-ukrishn@linux.vnet.ibm.com>

> On Sep 2, 2016, at 3:39 PM, Uma Krishnan <ukrishn@linux.vnet.ibm.com> =
wrote:
>=20
> Commit 704c4b0ddc03 ("cxlflash: Shutdown notify support for CXL Flash
> cards") was recently introduced to notify the AFU when a system is =
going
> down. Due to the position of the cxlflash driver in the device stack,
> cxlflash devices are _always_ removed during a reboot/shutdown. This =
can
> lead to a crash if the cxlflash shutdown hook is invoked _after_ the
> shutdown hook for the owning virtual PHB. Furthermore, the current
> implementation of shutdown/remove hooks for cxlflash are not tolerant =
to
> being invoked when the device is not enabled. This can also lead to a
> crash in situations where the remove hook is invoked after the device =
has
> been removed via the vPHBs shutdown hook. An example of this scenario
> would be an EEH reset failure while a reboot/shutdown is in progress.
>=20
> To solve both problems, the shutdown hook for cxlflash is updated to
> simply remove the device. This path already includes the AFU =
notification
> and thus this solution will continue to perform the original intent. =
At
> the same time, the remove hook is updated to protect against being
> called when the device is not enabled.
>=20
> Fixes: 704c4b0ddc03 ("cxlflash: Shutdown notify support for CXL Flash
> cards")
> Signed-off-by: Uma Krishna <ukrishn@linux.vnet.ibm.com>

Acked-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>

  parent reply	other threads:[~2016-09-07 23:46 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-02 20:36 [PATCH 0/6] cxlflash: Miscellaneous fixes Uma Krishnan
2016-09-02 20:36 ` Uma Krishnan
2016-09-02 20:38 ` [PATCH 1/6] cxlflash: Scan host only after the port is ready for I/O Uma Krishnan
2016-09-07 23:46   ` Matthew R. Ochs
2016-09-07 23:46     ` Matthew R. Ochs
2016-09-02 20:39 ` [PATCH 2/6] cxlflash: Remove the device cleanly in the system shutdown path Uma Krishnan
2016-09-05  7:12   ` Andrew Donnellan
2016-09-06 20:06     ` Uma Krishnan
2016-09-07 23:46   ` Matthew R. Ochs [this message]
2016-09-07 23:46     ` Matthew R. Ochs
2016-09-02 20:39 ` [PATCH 3/6] cxlflash: Fix to avoid EEH and host reset collisions Uma Krishnan
2016-09-09 22:13   ` Uma Krishnan
2016-09-14 16:48   ` Martin K. Petersen
2016-09-02 20:40 ` [PATCH 4/6] cxlflash: Improve EEH recovery time Uma Krishnan
2016-09-09 22:14   ` Uma Krishnan
2016-09-02 20:40 ` [PATCH 5/6] cxlflash: Refactor WWPN setup Uma Krishnan
2016-09-09 22:14   ` Uma Krishnan
2016-09-02 20:40 ` [PATCH 6/6] cxlflash: Fix context reference tracking on detach Uma Krishnan
2016-09-09 22:14   ` Uma Krishnan
2016-09-09 11:35 ` [PATCH 0/6] cxlflash: Miscellaneous fixes Martin K. Petersen

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