| Message ID | 0bfae28dbfb4cf86e80435639b92c7f4023041dc.1525343531.git.asutoshd@codeaurora.org (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Delegated to: | Andy Gross |
| Headers | show |
On 2018-05-03 04:07, Asutosh Das wrote: > From: Vijay Viswanath <vviswana@codeaurora.org> > > UFS driver can receive a request during memory reclaim by kswapd. > So when ufs driver puts the ungate work in queue, and if there are no > idle workers, kthreadd is invoked to create a new kworker. Since > kswapd task holds a mutex which kthreadd also needs, this can cause > a deadlock situation. So ungate work must be done in a separate > work queue with WQ_MEM_RECLAIM flag enabled. > Such a workqueue will have a rescue thread which will be called > when the above deadlock condition is possible. > > Signed-off-by: Vijay Viswanath <vviswana@codeaurora.org> > Signed-off-by: Can Guo <cang@codeaurora.org> > Signed-off-by: Asutosh Das <asutoshd@codeaurora.org> > --- > drivers/scsi/ufs/ufshcd.c | 11 ++++++++++- > drivers/scsi/ufs/ufshcd.h | 1 + > 2 files changed, 11 insertions(+), 1 deletion(-) > > diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c > index 557d538..3be61b7 100644 > --- a/drivers/scsi/ufs/ufshcd.c > +++ b/drivers/scsi/ufs/ufshcd.c > @@ -1483,7 +1483,8 @@ int ufshcd_hold(struct ufs_hba *hba, bool async) > hba->clk_gating.state = REQ_CLKS_ON; > trace_ufshcd_clk_gating(dev_name(hba->dev), > hba->clk_gating.state); > - schedule_work(&hba->clk_gating.ungate_work); > + queue_work(hba->clk_gating.clk_gating_workq, > + &hba->clk_gating.ungate_work); > /* > * fall through to check if we should wait for this > * work to be done or not. > @@ -1669,6 +1670,8 @@ static ssize_t > ufshcd_clkgate_enable_store(struct device *dev, > > static void ufshcd_init_clk_gating(struct ufs_hba *hba) > { > + char wq_name[sizeof("ufs_clk_gating_00")]; > + > if (!ufshcd_is_clkgating_allowed(hba)) > return; > > @@ -1676,6 +1679,11 @@ static void ufshcd_init_clk_gating(struct > ufs_hba *hba) > INIT_DELAYED_WORK(&hba->clk_gating.gate_work, ufshcd_gate_work); > INIT_WORK(&hba->clk_gating.ungate_work, ufshcd_ungate_work); > > + snprintf(wq_name, ARRAY_SIZE(wq_name), "ufs_clk_gating_%d", > + hba->host->host_no); > + hba->clk_gating.clk_gating_workq = alloc_ordered_workqueue(wq_name, > + WQ_MEM_RECLAIM); > + > hba->clk_gating.is_enabled = true; > > hba->clk_gating.delay_attr.show = ufshcd_clkgate_delay_show; > @@ -1703,6 +1711,7 @@ static void ufshcd_exit_clk_gating(struct ufs_hba > *hba) > device_remove_file(hba->dev, &hba->clk_gating.enable_attr); > cancel_work_sync(&hba->clk_gating.ungate_work); > cancel_delayed_work_sync(&hba->clk_gating.gate_work); > + destroy_workqueue(hba->clk_gating.clk_gating_workq); > } > > /* Must be called with host lock acquired */ > diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h > index 76c31d5..2e6bdc0 100644 > --- a/drivers/scsi/ufs/ufshcd.h > +++ b/drivers/scsi/ufs/ufshcd.h > @@ -361,6 +361,7 @@ struct ufs_clk_gating { > struct device_attribute enable_attr; > bool is_enabled; > int active_reqs; > + struct workqueue_struct *clk_gating_workq; > }; > > struct ufs_saved_pwr_info { Looks good to me. Reviewed-by: Subhash Jadavani <subhashj@codeaurora.org>
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c index 557d538..3be61b7 100644 --- a/drivers/scsi/ufs/ufshcd.c +++ b/drivers/scsi/ufs/ufshcd.c @@ -1483,7 +1483,8 @@ int ufshcd_hold(struct ufs_hba *hba, bool async) hba->clk_gating.state = REQ_CLKS_ON; trace_ufshcd_clk_gating(dev_name(hba->dev), hba->clk_gating.state); - schedule_work(&hba->clk_gating.ungate_work); + queue_work(hba->clk_gating.clk_gating_workq, + &hba->clk_gating.ungate_work); /* * fall through to check if we should wait for this * work to be done or not. @@ -1669,6 +1670,8 @@ static ssize_t ufshcd_clkgate_enable_store(struct device *dev, static void ufshcd_init_clk_gating(struct ufs_hba *hba) { + char wq_name[sizeof("ufs_clk_gating_00")]; + if (!ufshcd_is_clkgating_allowed(hba)) return; @@ -1676,6 +1679,11 @@ static void ufshcd_init_clk_gating(struct ufs_hba *hba) INIT_DELAYED_WORK(&hba->clk_gating.gate_work, ufshcd_gate_work); INIT_WORK(&hba->clk_gating.ungate_work, ufshcd_ungate_work); + snprintf(wq_name, ARRAY_SIZE(wq_name), "ufs_clk_gating_%d", + hba->host->host_no); + hba->clk_gating.clk_gating_workq = alloc_ordered_workqueue(wq_name, + WQ_MEM_RECLAIM); + hba->clk_gating.is_enabled = true; hba->clk_gating.delay_attr.show = ufshcd_clkgate_delay_show; @@ -1703,6 +1711,7 @@ static void ufshcd_exit_clk_gating(struct ufs_hba *hba) device_remove_file(hba->dev, &hba->clk_gating.enable_attr); cancel_work_sync(&hba->clk_gating.ungate_work); cancel_delayed_work_sync(&hba->clk_gating.gate_work); + destroy_workqueue(hba->clk_gating.clk_gating_workq); } /* Must be called with host lock acquired */ diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h index 76c31d5..2e6bdc0 100644 --- a/drivers/scsi/ufs/ufshcd.h +++ b/drivers/scsi/ufs/ufshcd.h @@ -361,6 +361,7 @@ struct ufs_clk_gating { struct device_attribute enable_attr; bool is_enabled; int active_reqs; + struct workqueue_struct *clk_gating_workq; }; struct ufs_saved_pwr_info {