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From: Adrian Hunter <adrian.hunter@intel.com>
To: Bart Van Assche <bvanassche@acm.org>,
	"Martin K . Petersen" <martin.petersen@oracle.com>
Cc: linux-scsi@vger.kernel.org, Jaegeuk Kim <jaegeuk@kernel.org>,
	Stanley Chu <stanley.chu@mediatek.com>,
	Can Guo <cang@codeaurora.org>,
	Asutosh Das <asutoshd@codeaurora.org>,
	Avri Altman <avri.altman@wdc.com>,
	"James E.J. Bottomley" <jejb@linux.ibm.com>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	Bean Huo <beanhuo@micron.com>,
	Kiwoong Kim <kwmad.kim@samsung.com>,
	Keoseong Park <keosung.park@samsung.com>
Subject: Re: [PATCH v3 16/18] scsi: ufs: Synchronize SCSI and UFS error handling
Date: Sat, 28 Aug 2021 12:47:20 +0300	[thread overview]
Message-ID: <88e0dc4c-34ff-6d87-fa9f-2fc924f50369@intel.com> (raw)
In-Reply-To: <20210722033439.26550-17-bvanassche@acm.org>

On 22/07/21 6:34 am, Bart Van Assche wrote:
> Use the SCSI error handler instead of a custom error handling strategy.
> This change reduces the number of potential races in the UFS drivers since
> the UFS error handler and the SCSI error handler no longer run concurrently.
> 
> Cc: Adrian Hunter <adrian.hunter@intel.com>
> Cc: Stanley Chu <stanley.chu@mediatek.com>
> Cc: Can Guo <cang@codeaurora.org>
> Cc: Asutosh Das <asutoshd@codeaurora.org>
> Cc: Avri Altman <avri.altman@wdc.com>
> Signed-off-by: Bart Van Assche <bvanassche@acm.org>
> ---

Hi

There is a deadlock that seems to be related to this patch, because now
requests are blocked while the error handler waits on the host_sem.


Example:

ufshcd_err_handler() races with ufshcd_wl_suspend() for host_sem.
ufshcd_wl_suspend() wins the race but now PM requests deadlock:

because:
 scsi_queue_rq() -> scsi_host_queue_ready() -> scsi_host_in_recovery() is FALSE

because:
 scsi_schedule_eh() has done:
	    scsi_host_set_state(shost, SHOST_RECOVERY) == 0 ||
	    scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY) == 0)


Some questions for thought:

Won't any holder of host_sem deadlock if it tries to do SCSI requests
and the error handler is waiting on host_sem?

Won't runtime resume deadlock if it is initiated by the error handler?


Regards
Adrian

  parent reply	other threads:[~2021-08-28  9:46 UTC|newest]

Thread overview: 67+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-22  3:34 [PATCH v3 00/18] UFS patches for kernel v5.15 Bart Van Assche
2021-07-22  3:34 ` [PATCH v3 01/18] scsi: ufs: Fix memory corruption by ufshcd_read_desc_param() Bart Van Assche
2021-07-25 12:40   ` Avri Altman
2021-07-22  3:34 ` [PATCH v3 02/18] scsi: ufs: Reduce power management code duplication Bart Van Assche
2021-07-31 14:44   ` Stanley Chu
2021-07-22  3:34 ` [PATCH v3 03/18] scsi: ufs: Only include power management code if necessary Bart Van Assche
2021-07-22  3:34 ` [PATCH v3 04/18] scsi: ufs: Rename the second ufshcd_probe_hba() argument Bart Van Assche
2021-08-02  8:17   ` Stanley Chu
2021-07-22  3:34 ` [PATCH v3 05/18] scsi: ufs: Use DECLARE_COMPLETION_ONSTACK() where appropriate Bart Van Assche
2021-07-22  3:34 ` [PATCH v3 06/18] scsi: ufs: Remove ufshcd_valid_tag() Bart Van Assche
2021-07-22  3:34 ` [PATCH v3 07/18] scsi: ufs: Verify UIC locking requirements at runtime Bart Van Assche
2021-07-22  3:34 ` [PATCH v3 08/18] scsi: ufs: Improve static type checking for the host controller state Bart Van Assche
2021-07-22  3:34 ` [PATCH v3 09/18] scsi: ufs: Remove several wmb() calls Bart Van Assche
2021-07-25 13:20   ` Avri Altman
2021-07-22  3:34 ` [PATCH v3 10/18] scsi: ufs: Inline ufshcd_outstanding_req_clear() Bart Van Assche
2021-07-29  7:42   ` Bean Huo
2021-07-22  3:34 ` [PATCH v3 11/18] scsi: ufs: Revert "Utilize Transfer Request List Completion Notification Register" Bart Van Assche
2021-07-29  8:03   ` Bean Huo
2021-07-29 16:10     ` Bart Van Assche
2021-07-29 16:13       ` Bart Van Assche
2021-07-29 21:14         ` Bean Huo
2021-08-02 15:24   ` Bean Huo
2021-08-03 18:49     ` Bart Van Assche
2021-07-22  3:34 ` [PATCH v3 12/18] scsi: ufs: Optimize serialization of setup_xfer_req() calls Bart Van Assche
2021-07-29  8:07   ` Bean Huo
2021-07-22  3:34 ` [PATCH v3 13/18] scsi: ufs: Optimize SCSI command processing Bart Van Assche
2021-07-29  9:12   ` Bean Huo
2021-07-29 16:11     ` Bart Van Assche
2021-08-02 12:11   ` Bean Huo
2021-07-22  3:34 ` [PATCH v3 14/18] scsi: ufs: Fix the SCSI abort handler Bart Van Assche
2021-08-02 13:15   ` Bean Huo
2021-07-22  3:34 ` [PATCH v3 15/18] scsi: ufs: Request sense data asynchronously Bart Van Assche
2021-08-02 13:16   ` Bean Huo
2021-07-22  3:34 ` [PATCH v3 16/18] scsi: ufs: Synchronize SCSI and UFS error handling Bart Van Assche
2021-08-02 14:24   ` Bean Huo
2021-08-28  9:47   ` Adrian Hunter [this message]
2021-08-29  7:17     ` Avri Altman
2021-08-29 21:33       ` Bart Van Assche
2021-08-29  9:57     ` Adrian Hunter
2021-08-29 22:18     ` Bart Van Assche
2021-08-31  7:24       ` Adrian Hunter
2021-08-31 10:04         ` Adrian Hunter
2021-08-31 17:18         ` Bart Van Assche
2021-09-01  7:42           ` Adrian Hunter
2021-09-01 20:46             ` Bart Van Assche
2021-09-02  6:02               ` Adrian Hunter
2021-07-22  3:34 ` [PATCH v3 17/18] scsi: ufs: Retry aborted SCSI commands instead of completing these successfully Bart Van Assche
2021-08-02 15:03   ` Bean Huo
2021-07-22  3:34 ` [PATCH v3 18/18] scsi: ufs: Add fault injection support Bart Van Assche
2021-08-02 15:03   ` Bean Huo
     [not found] ` <CGME20210722033524epcas2p31e41c1db6883aaa644edf23bbe8a1ca2@epcms2p4>
2021-07-28  6:48   ` [PATCH v3 06/18] scsi: ufs: Remove ufshcd_valid_tag() Daejun Park
2021-07-28 22:48     ` Bart Van Assche
     [not found]     ` <CGME20210722033524epcas2p31e41c1db6883aaa644edf23bbe8a1ca2@epcms2p7>
2021-07-29  0:26       ` Daejun Park
     [not found] ` <CGME20210722033530epcas2p4c76293e5fc5163fed3995acdd02678ce@epcms2p1>
2021-07-28  7:56   ` [PATCH v3 08/18] scsi: ufs: Improve static type checking for the host controller state Keoseong Park
     [not found] ` <CGME20210722033504epcas2p1cc3c6f61e81814004c36b89c7c9e3dd5@epcms2p5>
2021-07-29  0:56   ` [PATCH v3 01/18] scsi: ufs: Fix memory corruption by ufshcd_read_desc_param() Daejun Park
     [not found] ` <CGME20210722033510epcas2p410be4f2f387e98babeefc754a9fc1414@epcms2p2>
2021-07-29  0:56   ` [PATCH v3 02/18] scsi: ufs: Reduce power management code duplication Daejun Park
     [not found] ` <CGME20210722033513epcas2p22e4c2e6ea644992ede2739ebe381d53f@epcms2p8>
2021-07-29  0:56   ` [PATCH v3 03/18] scsi: ufs: Only include power management code if necessary Daejun Park
2021-07-31 14:48     ` Stanley Chu
     [not found] ` <CGME20210722033520epcas2p31c6f801eda7f100491c85e3f9c7d6600@epcms2p6>
2021-07-29  0:56   ` [PATCH v3 04/18] scsi: ufs: Rename the second ufshcd_probe_hba() argument Daejun Park
     [not found] ` <CGME20210722033523epcas2p22ea9a4afaeb46870638ff4429010a3c1@epcms2p7>
2021-07-29  0:57   ` [PATCH v3 05/18] scsi: ufs: Use DECLARE_COMPLETION_ONSTACK() where appropriate Daejun Park
     [not found] ` <CGME20210722033527epcas2p384eefb77dff85f5d8d59beede98b6bdc@epcms2p4>
2021-07-29  0:57   ` [PATCH v3 07/18] scsi: ufs: Verify UIC locking requirements at runtime Daejun Park
     [not found] ` <CGME20210722033531epcas2p4a4a975689ad7966d3db56dd81a7a255f@epcms2p1>
2021-07-29  0:57   ` [PATCH v3 08/18] scsi: ufs: Improve static type checking for the host controller state Daejun Park
     [not found] ` <CGME20210722033536epcas2p133eef1f5e2e5a1022ccef23e9c1035aa@epcms2p5>
2021-07-29  1:24   ` [PATCH v3 09/18] scsi: ufs: Remove several wmb() calls Daejun Park
     [not found] ` <CGME20210722033552epcas2p39f68ea806091ffa9755a25b778d70101@epcms2p2>
2021-07-29  1:25   ` [PATCH v3 12/18] scsi: ufs: Optimize serialization of setup_xfer_req() calls Daejun Park
     [not found] ` <CGME20210722033553epcas2p2818d9c1f046e8514415a72a4ddddc3db@epcms2p1>
2021-07-29  1:25   ` [PATCH v3 13/18] scsi: ufs: Optimize SCSI command processing Daejun Park
2021-08-03  2:13 ` [PATCH v3 00/18] UFS patches for kernel v5.15 Martin K. Petersen
2021-08-10  5:20 ` Martin K. Petersen

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