[PATCH] PCI: tegra: Convert struct tegra_msi mask_lock into raw spinlock

[PATCH] PCI: tegra: Convert struct tegra_msi mask_lock into raw spinlock

[Marek Vasut]

The tegra_msi_irq_unmask() function may be called from a PCI driver
request_threaded_irq() function. This triggers kernel/irq/manage.c
__setup_irq() which locks raw spinlock &desc->lock descriptor lock
and with that descriptor lock held, calls tegra_msi_irq_unmask().

Since the &desc->lock descriptor lock is a raw spinlock , and the
tegra_msi .mask_lock is not a raw spinlock, this setup triggers
'BUG: Invalid wait context' with CONFIG_PROVE_RAW_LOCK_NESTING=y .

Use scoped_guard() to simplify the locking.

Fixes: 2c99e55f7955 ("PCI: tegra: Convert to MSI domains")
Cc: stable@vger.kernel.org
Reported-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
---
Cc: "Krzysztof Wilczyński" <kwilczynski@kernel.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: Lorenzo Pieralisi <lpieralisi@kernel.org>
Cc: Manivannan Sadhasivam <mani@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Cc: linux-tegra@vger.kernel.org
---
NOTE: I don't have tegra hardware to test, this is based on input from Geert
      https://patchwork.kernel.org/project/linux-pci/patch/20250909162707.13927-2-marek.vasut+renesas@mailbox.org/#26574451
---
 drivers/pci/controller/pci-tegra.c | 27 +++++++++++++--------------
 1 file changed, 13 insertions(+), 14 deletions(-)

diff --git a/drivers/pci/controller/pci-tegra.c b/drivers/pci/controller/pci-tegra.c
index bb88767a37979..942ddfca3bf6b 100644
--- a/drivers/pci/controller/pci-tegra.c
+++ b/drivers/pci/controller/pci-tegra.c
@@ -14,6 +14,7 @@
  */
 
 #include <linux/clk.h>
+#include <linux/cleanup.h>
 #include <linux/debugfs.h>
 #include <linux/delay.h>
 #include <linux/export.h>
@@ -270,7 +271,7 @@ struct tegra_msi {
 	DECLARE_BITMAP(used, INT_PCI_MSI_NR);
 	struct irq_domain *domain;
 	struct mutex map_lock;
-	spinlock_t mask_lock;
+	raw_spinlock_t mask_lock;
 	void *virt;
 	dma_addr_t phys;
 	int irq;
@@ -1581,14 +1582,13 @@ static void tegra_msi_irq_mask(struct irq_data *d)
 	struct tegra_msi *msi = irq_data_get_irq_chip_data(d);
 	struct tegra_pcie *pcie = msi_to_pcie(msi);
 	unsigned int index = d->hwirq / 32;
-	unsigned long flags;
 	u32 value;
 
-	spin_lock_irqsave(&msi->mask_lock, flags);
-	value = afi_readl(pcie, AFI_MSI_EN_VEC(index));
-	value &= ~BIT(d->hwirq % 32);
-	afi_writel(pcie, value, AFI_MSI_EN_VEC(index));
-	spin_unlock_irqrestore(&msi->mask_lock, flags);
+	scoped_guard(raw_spinlock_irqsave, &msi->mask_lock) {
+		value = afi_readl(pcie, AFI_MSI_EN_VEC(index));
+		value &= ~BIT(d->hwirq % 32);
+		afi_writel(pcie, value, AFI_MSI_EN_VEC(index));
+	}
 }
 
 static void tegra_msi_irq_unmask(struct irq_data *d)
@@ -1596,14 +1596,13 @@ static void tegra_msi_irq_unmask(struct irq_data *d)
 	struct tegra_msi *msi = irq_data_get_irq_chip_data(d);
 	struct tegra_pcie *pcie = msi_to_pcie(msi);
 	unsigned int index = d->hwirq / 32;
-	unsigned long flags;
 	u32 value;
 
-	spin_lock_irqsave(&msi->mask_lock, flags);
-	value = afi_readl(pcie, AFI_MSI_EN_VEC(index));
-	value |= BIT(d->hwirq % 32);
-	afi_writel(pcie, value, AFI_MSI_EN_VEC(index));
-	spin_unlock_irqrestore(&msi->mask_lock, flags);
+	scoped_guard(raw_spinlock_irqsave, &msi->mask_lock) {
+		value = afi_readl(pcie, AFI_MSI_EN_VEC(index));
+		value |= BIT(d->hwirq % 32);
+		afi_writel(pcie, value, AFI_MSI_EN_VEC(index));
+	}
 }
 
 static void tegra_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
@@ -1711,7 +1710,7 @@ static int tegra_pcie_msi_setup(struct tegra_pcie *pcie)
 	int err;
 
 	mutex_init(&msi->map_lock);
-	spin_lock_init(&msi->mask_lock);
+	raw_spin_lock_init(&msi->mask_lock);
 
 	if (IS_ENABLED(CONFIG_PCI_MSI)) {
 		err = tegra_allocate_domains(msi);
-- 
2.51.0

Re: [PATCH] PCI: tegra: Convert struct tegra_msi mask_lock into raw spinlock

[Manivannan Sadhasivam]

On Mon, 22 Sep 2025 17:07:48 +0200, Marek Vasut wrote:
> The tegra_msi_irq_unmask() function may be called from a PCI driver
> request_threaded_irq() function. This triggers kernel/irq/manage.c
> __setup_irq() which locks raw spinlock &desc->lock descriptor lock
> and with that descriptor lock held, calls tegra_msi_irq_unmask().
> 
> Since the &desc->lock descriptor lock is a raw spinlock , and the
> tegra_msi .mask_lock is not a raw spinlock, this setup triggers
> 'BUG: Invalid wait context' with CONFIG_PROVE_RAW_LOCK_NESTING=y .
> 
> [...]

Applied, thanks!

[1/1] PCI: tegra: Convert struct tegra_msi mask_lock into raw spinlock
      commit: 39ec28d01d565030aa28d87a212d201c252c072e

Best regards,
-- 
Manivannan Sadhasivam <mani@kernel.org>