From: Asutosh Das <asutoshd@codeaurora.org>
To: subhashj@codeaurora.org, cang@codeaurora.org,
vivek.gautam@codeaurora.org, rnayak@codeaurora.org,
vinholikatti@gmail.com, jejb@linux.vnet.ibm.com,
martin.petersen@oracle.com
Cc: linux-scsi@vger.kernel.org,
Vijay Viswanath <vviswana@codeaurora.org>,
Asutosh Das <asutoshd@codeaurora.org>,
linux-kernel@vger.kernel.org (open list)
Subject: [PATCH 9/9] scsi: ufs: Add clock ungating to a separate workqueue
Date: Wed, 21 Feb 2018 10:26:40 +0530 [thread overview]
Message-ID: <1c92a979dce897db920d9b9a625923d64cba2266.1519120988.git.asutoshd@codeaurora.org> (raw)
In-Reply-To: <cover.1519120988.git.asutoshd@codeaurora.org>
In-Reply-To: <cover.1519120988.git.asutoshd@codeaurora.org>
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
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);
+
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.
next prev parent reply other threads:[~2018-02-21 5:03 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <cover.1519120988.git.asutoshd@codeaurora.org>
2018-02-21 4:56 ` [PATCH 1/9] scsi: ufs: Allowing power mode change Asutosh Das
2018-02-23 5:10 ` Kyuho Choi
2018-02-23 7:03 ` Asutosh Das (asd)
2018-02-21 4:56 ` [PATCH 2/9] scsi: ufs: Add LCC quirk for host and device Asutosh Das
2018-02-21 4:56 ` [PATCH 3/9] scsi: ufs: fix exception event handling Asutosh Das
2018-02-21 4:56 ` [PATCH 4/9] scsi: ufshcd: fix possible unclocked register access Asutosh Das
2018-02-21 4:56 ` [PATCH 5/9] scsi: ufs: add reference counting for scsi block requests Asutosh Das
2018-02-21 13:18 ` Stanislav Nijnikov
2018-02-23 2:31 ` Asutosh Das (asd)
2018-02-21 4:56 ` [PATCH 6/9] scsi: ufs-qcom: remove broken hci version quirk Asutosh Das
2018-02-21 4:56 ` [PATCH 7/9] scsi: ufs: make sure all interrupts are processed Asutosh Das
2018-02-21 4:56 ` [PATCH 8/9] scsi: ufs: fix irq return code Asutosh Das
2018-02-21 4:56 ` Asutosh Das [this message]
2018-02-23 23:57 ` [PATCH 9/9] scsi: ufs: Add clock ungating to a separate workqueue Miguel Ojeda
2018-02-26 3:55 ` Asutosh Das (asd)
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