Messages in this thread | | | Date | Wed, 12 Apr 2023 23:08:31 -0700 | Subject | Re: [PATCH v1 1/5] ufs: mcq: Add supporting functions for mcq abort | From | "Bao D. Nguyen" <> |
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On 4/11/2023 6:14 AM, Powen Kao (高伯文) wrote: > Hi Bao D., > > We have done some test based on your RFC v3 patches and an issue is > reported.
Hi Powen,
Thank you very much for catching this issue. It seems that I cannot use read_poll_timeout() because it sleeps while holding the spin_lock().
I will make the change to poll the registers in a tight loop with udelay(20) polling interval in the next revision.
Thanks, Bao
> > kworker/u16:4: BUG: scheduling while atomic: > kworker/u16:4/5736/0x00000002 > kworker/u16:4: [name:core&]Preemption disabled at: > kworker/u16:4: [<ffffffef97e33024>] ufshcd_mcq_sq_cleanup+0x9c/0x27c > kworker/u16:4: CPU: 2 PID: 5736 Comm: kworker/u16:4 Tainted: G > S W OE > kworker/u16:4: Workqueue: ufs_eh_wq_0 ufshcd_err_handler > kworker/u16:4: Call trace: > kworker/u16:4: dump_backtrace+0x108/0x15c > kworker/u16:4: show_stack+0x20/0x30 > kworker/u16:4: dump_stack_lvl+0x6c/0x8c > kworker/u16:4: dump_stack+0x20/0x44 > kworker/u16:4: __schedule_bug+0xd4/0x100 > kworker/u16:4: __schedule+0x660/0xa5c > kworker/u16:4: schedule+0x80/0xec > kworker/u16:4: schedule_hrtimeout_range_clock+0xa0/0x140 > kworker/u16:4: schedule_hrtimeout_range+0x1c/0x30 > kworker/u16:4: usleep_range_state+0x88/0xd8 > kworker/u16:4: ufshcd_mcq_sq_cleanup+0x170/0x27c > kworker/u16:4: ufshcd_clear_cmds+0x78/0x184 > kworker/u16:4: ufshcd_wait_for_dev_cmd+0x234/0x348 > kworker/u16:4: ufshcd_exec_dev_cmd+0x220/0x298 > kworker/u16:4: ufshcd_verify_dev_init+0x68/0x124 > kworker/u16:4: ufshcd_probe_hba+0x390/0x9bc > kworker/u16:4: ufshcd_host_reset_and_restore+0x74/0x158 > kworker/u16:4: ufshcd_reset_and_restore+0x70/0x31c > kworker/u16:4: ufshcd_err_handler+0xad4/0xe58 > kworker/u16:4: process_one_work+0x214/0x5b8 > kworker/u16:4: worker_thread+0x2d4/0x448 > kworker/u16:4: kthread+0x110/0x1e0 > kworker/u16:4: ret_from_fork+0x10/0x20 > kworker/u16:4: ------------[ cut here ]------------ > > > On Wed, 2023-03-29 at 03:01 -0700, Bao D. Nguyen wrote: > >> +/** >> + * ufshcd_mcq_sq_cleanup - Clean up Submission Queue resources >> + * associated with the pending command. >> + * @hba - per adapter instance. >> + * @task_tag - The command's task tag. >> + * @result - Result of the Clean up operation. >> + * >> + * Returns 0 and result on completion. Returns error code if >> + * the operation fails. >> + */ >> +int ufshcd_mcq_sq_cleanup(struct ufs_hba *hba, int task_tag, int >> *result) >> +{ >> + struct ufshcd_lrb *lrbp = &hba->lrb[task_tag]; >> + struct scsi_cmnd *cmd = lrbp->cmd; >> + struct ufs_hw_queue *hwq; >> + void __iomem *reg, *opr_sqd_base; >> + u32 nexus, i, val; >> + int err; >> + >> + if (task_tag != hba->nutrs - UFSHCD_NUM_RESERVED) { >> + if (!cmd) >> + return FAILED; >> + hwq = ufshcd_mcq_req_to_hwq(hba, >> scsi_cmd_to_rq(cmd)); >> + } else { >> + hwq = hba->dev_cmd_queue; >> + } >> + >> + i = hwq->id; >> + >> + spin_lock(&hwq->sq_lock); > As spin_lock() disable preemption > >> + >> + /* stop the SQ fetching before working on it */ >> + err = ufshcd_mcq_sq_stop(hba, hwq); >> + if (err) >> + goto unlock; >> + >> + /* SQCTI = EXT_IID, IID, LUN, Task Tag */ >> + nexus = lrbp->lun << 8 | task_tag; >> + opr_sqd_base = mcq_opr_base(hba, OPR_SQD, i); >> + writel(nexus, opr_sqd_base + REG_SQCTI); >> + >> + /* SQRTCy.ICU = 1 */ >> + writel(SQ_ICU, opr_sqd_base + REG_SQRTC); >> + >> + /* Poll SQRTSy.CUS = 1. Return result from SQRTSy.RTC */ >> + reg = opr_sqd_base + REG_SQRTS; >> + err = read_poll_timeout(readl, val, val & SQ_CUS, 20, >> + MCQ_POLL_US, false, reg); > read_poll_timeout() was ufshcd_mcq_poll_register() in last patch, > right? ufshcd_mcq_poll_register() calls usleep_range() causing KE as > reported above. Same issue seems to still exist as read_poll_timeout() > sleeps. > > Skipping ufshcd_mcq_sq_cleanup() by returning FAILED directly to > trigger reset in ufshcd error handler successfully recover host. > > BTW, is there maybe a change list between RFC v3 and this v1 patch? :) > Thanks > > Po-Wen > >
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