[1/2] PCI: Make pci_msi_setup_pci_dev() non-static for use by arch code

Commit Message

Michael Ellerman Aug. 24, 2015, 12:42 p.m. UTC

From: "Guilherme G. Piccoli" <[e-mail]>

Commit 1851617cd2da ("PCI/MSI: Disable MSI at enumeration even if kernel
doesn't support MSI") changed the location of the code that initialises
dev->msi_cap/msix_cap and then disables MSI/MSI-X interrupts at PCI
probe time in devices that have this flag set. It moved the code from
pci_msi_init_pci_dev() to a new function named pci_msi_setup_pci_dev(),
called by pci_setup_device().

The pseries PCI probing code does not call pci_setup_device(), so since
the aforementioned commit the function pci_msi_setup_pci_dev() is not
called and MSI/MSI-X interrupts are left enabled. Additionally because
dev->msi_cap/msix_cap are not initialised no driver can ever enable
MSI/MSI-X.

To fix this, the pseries PCI probe should manually call
pci_msi_setup_pci_dev(), so this patch makes it non-static.

Fixes: 1851617cd2da ("PCI/MSI: Disable MSI at enumeration even if kernel doesn't support MSI")
[mpe: Update change log to mention dev->msi_cap/msix_cap]
Signed-off-by: Guilherme G. Piccoli <[e-mail]>
Signed-off-by: Michael Ellerman <[e-mail]>
---
 drivers/pci/probe.c | 2 +-
 include/linux/pci.h | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)


Bjorn, I plan to put this series in my fixes branch and ask Linus to pull it
before the 4.2 release. Unless you want to take it.

Comments

Michael Ellerman Aug. 26, 2015, 12:23 p.m. UTC | #1

On Mon, 2015-24-08 at 12:42:46 UTC, Michael Ellerman wrote:
> From: "Guilherme G. Piccoli" <[e-mail]>
> 
> Commit 1851617cd2da ("PCI/MSI: Disable MSI at enumeration even if kernel
> doesn't support MSI") changed the location of the code that initialises
> dev->msi_cap/msix_cap and then disables MSI/MSI-X interrupts at PCI
> probe time in devices that have this flag set. It moved the code from
> pci_msi_init_pci_dev() to a new function named pci_msi_setup_pci_dev(),
> called by pci_setup_device().
> 
> The pseries PCI probing code does not call pci_setup_device(), so since
> the aforementioned commit the function pci_msi_setup_pci_dev() is not
> called and MSI/MSI-X interrupts are left enabled. Additionally because
> dev->msi_cap/msix_cap are not initialised no driver can ever enable
> MSI/MSI-X.
> 
> To fix this, the pseries PCI probe should manually call
> pci_msi_setup_pci_dev(), so this patch makes it non-static.
> 
> Fixes: 1851617cd2da ("PCI/MSI: Disable MSI at enumeration even if kernel doesn't support MSI")
> [mpe: Update change log to mention dev->msi_cap/msix_cap]
> Signed-off-by: Guilherme G. Piccoli <[e-mail]>
> Signed-off-by: Michael Ellerman <[e-mail]>

Applied to powerpc fixes.

https://git.kernel.org/powerpc/c/22b6839b914bbe5d94de11bb

cheers
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Patch

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index b978bbfe044c..f6ae0d0052eb 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1108,7 +1108,7 @@  int pci_cfg_space_size(struct pci_dev *dev)
 
 #define LEGACY_IO_RESOURCE	(IORESOURCE_IO | IORESOURCE_PCI_FIXED)
 
-static void pci_msi_setup_pci_dev(struct pci_dev *dev)
+void pci_msi_setup_pci_dev(struct pci_dev *dev)
 {
 	/*
 	 * Disable the MSI hardware to avoid screaming interrupts
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 8a0321a8fb59..860c751810fc 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1202,6 +1202,7 @@  struct msix_entry {
 	u16	entry;	/* driver uses to specify entry, OS writes */
 };
 
+void pci_msi_setup_pci_dev(struct pci_dev *dev);
 
 #ifdef CONFIG_PCI_MSI
 int pci_msi_vec_count(struct pci_dev *dev);