Message ID | cover.1619223249.git.asutoshd@codeaurora.org |
---|---|
Headers | show |
Series | Enable power management for ufs wlun | expand |
On 24/04/21 3:20 am, Asutosh Das wrote: > During runtime-suspend of ufs host, the scsi devices are > already suspended and so are the queues associated with them. > But the ufs host sends SSU (START_STOP_UNIT) to wlun > during its runtime-suspend. > During the process blk_queue_enter checks if the queue is not in > suspended state. If so, it waits for the queue to resume, and never > comes out of it. > The commit > (d55d15a33: scsi: block: Do not accept any requests while suspended) > adds the check if the queue is in suspended state in blk_queue_enter(). > > Call trace: > __switch_to+0x174/0x2c4 > __schedule+0x478/0x764 > schedule+0x9c/0xe0 > blk_queue_enter+0x158/0x228 > blk_mq_alloc_request+0x40/0xa4 > blk_get_request+0x2c/0x70 > __scsi_execute+0x60/0x1c4 > ufshcd_set_dev_pwr_mode+0x124/0x1e4 > ufshcd_suspend+0x208/0x83c > ufshcd_runtime_suspend+0x40/0x154 > ufshcd_pltfrm_runtime_suspend+0x14/0x20 > pm_generic_runtime_suspend+0x28/0x3c > __rpm_callback+0x80/0x2a4 > rpm_suspend+0x308/0x614 > rpm_idle+0x158/0x228 > pm_runtime_work+0x84/0xac > process_one_work+0x1f0/0x470 > worker_thread+0x26c/0x4c8 > kthread+0x13c/0x320 > ret_from_fork+0x10/0x18 > > Fix this by registering ufs device wlun as a scsi driver and > registering it for block runtime-pm. Also make this as a > supplier for all other luns. That way, this device wlun > suspends after all the consumers and resumes after > hba resumes. This also registers a new scsi driver for rpmb wlun. > This new driver is mostly used to clear rpmb uac. > > Fixed smatch warnings: > Reported-by: kernel test robot <lkp@intel.com> > Reported-by: Dan Carpenter <dan.carpenter@oracle.com> > > Co-developed-by: Can Guo <cang@codeaurora.org> > Signed-off-by: Can Guo <cang@codeaurora.org> > Signed-off-by: Asutosh Das <asutoshd@codeaurora.org> Note we don't use regulators, clocks, clock scaling or gating. Although those things do look OK. Notwithstanding that: Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>
Asutosh,
> This patch attempts to fix a deadlock in ufs while sending SSU.
Applied to 5.14/scsi-staging, thanks!
--
Martin K. Petersen Oracle Linux Engineering
> Asutosh, In several places there is now a reference: "Also check the description of __ufshcd_wl_suspend()" But no such description is to found. Might want to add it in a supplementary patch? Thanks, Avri > > > This patch attempts to fix a deadlock in ufs while sending SSU. > > Applied to 5.14/scsi-staging, thanks! > > -- > Martin K. Petersen Oracle Linux Engineering
On Fri, 23 Apr 2021 17:20:15 -0700, Asutosh Das wrote: > This patch attempts to fix a deadlock in ufs while sending SSU. > Recently, blk_queue_enter() added a check to not process requests if the > queue is suspended. That leads to a resume of the associated device which > is suspended. In ufs, that device is ufs device wlun and it's parent is > ufs_hba. This resume tries to resume ufs device wlun which in turn tries > to resume ufs_hba, which is already in the process of suspending, thus > causing a deadlock. > > [...] Applied to 5.14/scsi-queue, thanks! [1/2] scsi: ufs: Enable power management for wlun https://git.kernel.org/mkp/scsi/c/b294ff3e3449 [2/2] ufs: sysfs: Resume the proper scsi device https://git.kernel.org/mkp/scsi/c/aef80fd1da32 -- Martin K. Petersen Oracle Linux Engineering