[4.2.y-ckt stable] Patch "PCI: host: Mark PCIe/PCI (MSI) IRQ cascade handlers as IRQF_NO_THREAD" has been added to the 4.2.y-ckt tree
Kamal Mostafa
kamal at canonical.com
Wed Jan 27 00:11:09 UTC 2016
This is a note to let you know that I have just added a patch titled
PCI: host: Mark PCIe/PCI (MSI) IRQ cascade handlers as IRQF_NO_THREAD
to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree
which can be found at:
http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-4.2.y-queue
This patch is scheduled to be released in version 4.2.8-ckt3.
If you, or anyone else, feels it should not be added to this tree, please
reply to this email.
For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
Thanks.
-Kamal
---8<------------------------------------------------------------
>From 6e835dbb5b2d6bc757382e9aa0222f86a0c47885 Mon Sep 17 00:00:00 2001
From: Grygorii Strashko <grygorii.strashko at ti.com>
Date: Thu, 10 Dec 2015 21:18:20 +0200
Subject: PCI: host: Mark PCIe/PCI (MSI) IRQ cascade handlers as IRQF_NO_THREAD
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
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commit 8ff0ef996ca00028519c70e8d51d32bd37eb51dc upstream.
On -RT and if kernel is booting with "threadirqs" cmd line parameter,
PCIe/PCI (MSI) IRQ cascade handlers (like dra7xx_pcie_msi_irq_handler())
will be forced threaded and, as result, will generate warnings like this:
WARNING: CPU: 1 PID: 82 at kernel/irq/handle.c:150 handle_irq_event_percpu+0x14c/0x174()
irq 460 handler irq_default_primary_handler+0x0/0x14 enabled interrupts
Backtrace:
(warn_slowpath_common) from (warn_slowpath_fmt+0x38/0x40)
(warn_slowpath_fmt) from (handle_irq_event_percpu+0x14c/0x174)
(handle_irq_event_percpu) from (handle_irq_event+0x84/0xb8)
(handle_irq_event) from (handle_simple_irq+0x90/0x118)
(handle_simple_irq) from (generic_handle_irq+0x30/0x44)
(generic_handle_irq) from (dra7xx_pcie_msi_irq_handler+0x7c/0x8c)
(dra7xx_pcie_msi_irq_handler) from (irq_forced_thread_fn+0x28/0x5c)
(irq_forced_thread_fn) from (irq_thread+0x128/0x204)
This happens because all of them invoke generic_handle_irq() from the
requested handler. generic_handle_irq() grabs raw_locks and thus needs to
run in raw-IRQ context.
This issue was originally reproduced on TI dra7-evem, but, as was
identified during discussion [1], other hosts can also suffer from this
issue. Fix all them at once by marking PCIe/PCI (MSI) IRQ cascade handlers
IRQF_NO_THREAD explicitly.
[1] http://lkml.kernel.org/r/1448027966-21610-1-git-send-email-grygorii.strashko@ti.com
[bhelgaas: add stable tag, fix typos]
Signed-off-by: Grygorii Strashko <grygorii.strashko at ti.com>
Signed-off-by: Bjorn Helgaas <bhelgaas at google.com>
Acked-by: Lucas Stach <l.stach at pengutronix.de> (for imx6)
CC: Kishon Vijay Abraham I <kishon at ti.com>
CC: Jingoo Han <jingoohan1 at gmail.com>
CC: Kukjin Kim <kgene at kernel.org>
CC: Krzysztof Kozlowski <k.kozlowski at samsung.com>
CC: Richard Zhu <Richard.Zhu at freescale.com>
CC: Thierry Reding <thierry.reding at gmail.com>
CC: Stephen Warren <swarren at wwwdotorg.org>
CC: Alexandre Courbot <gnurou at gmail.com>
CC: Simon Horman <horms at verge.net.au>
CC: Pratyush Anand <pratyush.anand at gmail.com>
CC: Michal Simek <michal.simek at xilinx.com>
CC: "Sören Brinkmann" <soren.brinkmann at xilinx.com>
CC: Sebastian Andrzej Siewior <bigeasy at linutronix.de>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
drivers/pci/host/pci-dra7xx.c | 3 ++-
drivers/pci/host/pci-exynos.c | 3 ++-
drivers/pci/host/pci-imx6.c | 3 ++-
drivers/pci/host/pci-tegra.c | 2 +-
drivers/pci/host/pcie-rcar.c | 6 ++++--
drivers/pci/host/pcie-spear13xx.c | 3 ++-
drivers/pci/host/pcie-xilinx.c | 3 ++-
7 files changed, 15 insertions(+), 8 deletions(-)
diff --git a/drivers/pci/host/pci-dra7xx.c b/drivers/pci/host/pci-dra7xx.c
index 80db09e..66aa928 100644
--- a/drivers/pci/host/pci-dra7xx.c
+++ b/drivers/pci/host/pci-dra7xx.c
@@ -284,7 +284,8 @@ static int __init dra7xx_add_pcie_port(struct dra7xx_pcie *dra7xx,
}
ret = devm_request_irq(&pdev->dev, pp->irq,
- dra7xx_pcie_msi_irq_handler, IRQF_SHARED,
+ dra7xx_pcie_msi_irq_handler,
+ IRQF_SHARED | IRQF_NO_THREAD,
"dra7-pcie-msi", pp);
if (ret) {
dev_err(&pdev->dev, "failed to request irq\n");
diff --git a/drivers/pci/host/pci-exynos.c b/drivers/pci/host/pci-exynos.c
index f9f468d..7b6be77 100644
--- a/drivers/pci/host/pci-exynos.c
+++ b/drivers/pci/host/pci-exynos.c
@@ -523,7 +523,8 @@ static int __init exynos_add_pcie_port(struct pcie_port *pp,
ret = devm_request_irq(&pdev->dev, pp->msi_irq,
exynos_pcie_msi_irq_handler,
- IRQF_SHARED, "exynos-pcie", pp);
+ IRQF_SHARED | IRQF_NO_THREAD,
+ "exynos-pcie", pp);
if (ret) {
dev_err(&pdev->dev, "failed to request msi irq\n");
return ret;
diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c
index 233a196..fd5eb2e 100644
--- a/drivers/pci/host/pci-imx6.c
+++ b/drivers/pci/host/pci-imx6.c
@@ -544,7 +544,8 @@ static int __init imx6_add_pcie_port(struct pcie_port *pp,
ret = devm_request_irq(&pdev->dev, pp->msi_irq,
imx6_pcie_msi_handler,
- IRQF_SHARED, "mx6-pcie-msi", pp);
+ IRQF_SHARED | IRQF_NO_THREAD,
+ "mx6-pcie-msi", pp);
if (ret) {
dev_err(&pdev->dev, "failed to request MSI irq\n");
return -ENODEV;
diff --git a/drivers/pci/host/pci-tegra.c b/drivers/pci/host/pci-tegra.c
index 10c0571..60e3c46 100644
--- a/drivers/pci/host/pci-tegra.c
+++ b/drivers/pci/host/pci-tegra.c
@@ -1289,7 +1289,7 @@ static int tegra_pcie_enable_msi(struct tegra_pcie *pcie)
msi->irq = err;
- err = request_irq(msi->irq, tegra_pcie_msi_irq, 0,
+ err = request_irq(msi->irq, tegra_pcie_msi_irq, IRQF_NO_THREAD,
tegra_msi_irq_chip.name, pcie);
if (err < 0) {
dev_err(&pdev->dev, "failed to request IRQ: %d\n", err);
diff --git a/drivers/pci/host/pcie-rcar.c b/drivers/pci/host/pcie-rcar.c
index c086210..56ce564 100644
--- a/drivers/pci/host/pcie-rcar.c
+++ b/drivers/pci/host/pcie-rcar.c
@@ -695,14 +695,16 @@ static int rcar_pcie_enable_msi(struct rcar_pcie *pcie)
/* Two irqs are for MSI, but they are also used for non-MSI irqs */
err = devm_request_irq(&pdev->dev, msi->irq1, rcar_pcie_msi_irq,
- IRQF_SHARED, rcar_msi_irq_chip.name, pcie);
+ IRQF_SHARED | IRQF_NO_THREAD,
+ rcar_msi_irq_chip.name, pcie);
if (err < 0) {
dev_err(&pdev->dev, "failed to request IRQ: %d\n", err);
goto err;
}
err = devm_request_irq(&pdev->dev, msi->irq2, rcar_pcie_msi_irq,
- IRQF_SHARED, rcar_msi_irq_chip.name, pcie);
+ IRQF_SHARED | IRQF_NO_THREAD,
+ rcar_msi_irq_chip.name, pcie);
if (err < 0) {
dev_err(&pdev->dev, "failed to request IRQ: %d\n", err);
goto err;
diff --git a/drivers/pci/host/pcie-spear13xx.c b/drivers/pci/host/pcie-spear13xx.c
index 4086268..d877c3b 100644
--- a/drivers/pci/host/pcie-spear13xx.c
+++ b/drivers/pci/host/pcie-spear13xx.c
@@ -282,7 +282,8 @@ static int spear13xx_add_pcie_port(struct pcie_port *pp,
return -ENODEV;
}
ret = devm_request_irq(dev, pp->irq, spear13xx_pcie_irq_handler,
- IRQF_SHARED, "spear1340-pcie", pp);
+ IRQF_SHARED | IRQF_NO_THREAD,
+ "spear1340-pcie", pp);
if (ret) {
dev_err(dev, "failed to request irq %d\n", pp->irq);
return ret;
diff --git a/drivers/pci/host/pcie-xilinx.c b/drivers/pci/host/pcie-xilinx.c
index f1a06a0..577fe5b 100644
--- a/drivers/pci/host/pcie-xilinx.c
+++ b/drivers/pci/host/pcie-xilinx.c
@@ -776,7 +776,8 @@ static int xilinx_pcie_parse_dt(struct xilinx_pcie_port *port)
port->irq = irq_of_parse_and_map(node, 0);
err = devm_request_irq(dev, port->irq, xilinx_pcie_intr_handler,
- IRQF_SHARED, "xilinx-pcie", port);
+ IRQF_SHARED | IRQF_NO_THREAD,
+ "xilinx-pcie", port);
if (err) {
dev_err(dev, "unable to request irq %d\n", port->irq);
return err;
--
1.9.1
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