| Message ID | 1c92a979dce897db920d9b9a625923d64cba2266.1519120988.git.asutoshd@codeaurora.org (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
On Wed, Feb 21, 2018 at 5:56 AM, Asutosh Das <asutoshd@codeaurora.org> 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__RECLAIM flag enabled.Such a workqueue will have WQ_MEM_RECLAIM here. Also space after dot. > 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 | 10 +++++++++- > drivers/scsi/ufs/ufshcd.h | 1 + > 2 files changed, 10 insertions(+), 1 deletion(-) > > diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c > index 6541e1d..bb3382a 100644 > --- a/drivers/scsi/ufs/ufshcd.c > +++ b/drivers/scsi/ufs/ufshcd.c > @@ -1503,7 +1503,8 @@ 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. > @@ -1689,6 +1690,8 @@ 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; > > @@ -1696,6 +1699,10 @@ 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 = create_singlethread_workqueue(wq_name); Shouldn't this be alloc_ordered_workqueue() with WQ_MEM_RECLAIM then? (create_singlethread_workqueue() and friends are deprecated). Cheers, Miguel > + > hba->clk_gating.is_enabled = true; > > hba->clk_gating.delay_attr.show = ufshcd_clkgate_delay_show; > @@ -1723,6 +1730,7 @@ 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 4385741..570c33e 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 { > -- > Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc. > Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project. >
On 2/24/2018 5:27 AM, Miguel Ojeda wrote: > On Wed, Feb 21, 2018 at 5:56 AM, Asutosh Das <asutoshd@codeaurora.org> 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__RECLAIM flag enabled.Such a workqueue will have > > WQ_MEM_RECLAIM here. Also space after dot. > >> 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 | 10 +++++++++- >> drivers/scsi/ufs/ufshcd.h | 1 + >> 2 files changed, 10 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c >> index 6541e1d..bb3382a 100644 >> --- a/drivers/scsi/ufs/ufshcd.c >> +++ b/drivers/scsi/ufs/ufshcd.c >> @@ -1503,7 +1503,8 @@ 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. >> @@ -1689,6 +1690,8 @@ 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; >> >> @@ -1696,6 +1699,10 @@ 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 = create_singlethread_workqueue(wq_name); > > Shouldn't this be alloc_ordered_workqueue() with WQ_MEM_RECLAIM then? > (create_singlethread_workqueue() and friends are deprecated). > > Cheers, > Miguel > >> + >> hba->clk_gating.is_enabled = true; >> >> hba->clk_gating.delay_attr.show = ufshcd_clkgate_delay_show; >> @@ -1723,6 +1730,7 @@ 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 4385741..570c33e 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 { >> -- >> Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center, Inc. >> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project. >> Hi Miguel Thanks for the review. I'll check this and put up the changes in v2. -asd
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c index 6541e1d..bb3382a 100644 --- a/drivers/scsi/ufs/ufshcd.c +++ b/drivers/scsi/ufs/ufshcd.c @@ -1503,7 +1503,8 @@ 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. @@ -1689,6 +1690,8 @@ 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; @@ -1696,6 +1699,10 @@ 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 = create_singlethread_workqueue(wq_name); + hba->clk_gating.is_enabled = true; hba->clk_gating.delay_attr.show = ufshcd_clkgate_delay_show; @@ -1723,6 +1730,7 @@ 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 4385741..570c33e 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 {