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authorThomas Gleixner <tglx@linutronix.de>2021-07-30 00:51:47 +0300
committerThomas Gleixner <tglx@linutronix.de>2021-08-10 11:59:20 +0300
commit77e89afc25f30abd56e76a809ee2884d7c1b63ce (patch)
tree326a03295c46c3b298db459f8a86441f3a8b0de8 /include/linux/msi.h
parentd28d4ad2a1aef27458b3383725bb179beb8d015c (diff)
downloadlinux-77e89afc25f30abd56e76a809ee2884d7c1b63ce.tar.xz
PCI/MSI: Protect msi_desc::masked for multi-MSI
Multi-MSI uses a single MSI descriptor and there is a single mask register when the device supports per vector masking. To avoid reading back the mask register the value is cached in the MSI descriptor and updates are done by clearing and setting bits in the cache and writing it to the device. But nothing protects msi_desc::masked and the mask register from being modified concurrently on two different CPUs for two different Linux interrupts which belong to the same multi-MSI descriptor. Add a lock to struct device and protect any operation on the mask and the mask register with it. This makes the update of msi_desc::masked unconditional, but there is no place which requires a modification of the hardware register without updating the masked cache. msi_mask_irq() is now an empty wrapper which will be cleaned up in follow up changes. The problem goes way back to the initial support of multi-MSI, but picking the commit which introduced the mask cache is a valid cut off point (2.6.30). Fixes: f2440d9acbe8 ("PCI MSI: Refactor interrupt masking code") Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Marc Zyngier <maz@kernel.org> Reviewed-by: Marc Zyngier <maz@kernel.org> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20210729222542.726833414@linutronix.de
Diffstat (limited to 'include/linux/msi.h')
-rw-r--r--include/linux/msi.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/msi.h b/include/linux/msi.h
index 6aff469e511d..e8bdcb83172b 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -233,7 +233,7 @@ void __pci_read_msi_msg(struct msi_desc *entry, struct msi_msg *msg);
void __pci_write_msi_msg(struct msi_desc *entry, struct msi_msg *msg);
u32 __pci_msix_desc_mask_irq(struct msi_desc *desc, u32 flag);
-u32 __pci_msi_desc_mask_irq(struct msi_desc *desc, u32 mask, u32 flag);
+void __pci_msi_desc_mask_irq(struct msi_desc *desc, u32 mask, u32 flag);
void pci_msi_mask_irq(struct irq_data *data);
void pci_msi_unmask_irq(struct irq_data *data);