Re: [patch 27/39] PCI/MSI: Move pci_disable_msix() to api.c

[Thomas Gleixner]

On Wed, Nov 16 2022 at 10:26, Bjorn Helgaas wrote:
>>  /**
>> + * pci_disable_msix() - Disable MSI-X interrupt mode on device
>> + * @dev: the PCI device to operate on
>> + *
>> + * Legacy device driver API to disable MSI-X interrupt mode on device,
>> + * free earlier-allocated interrupt vectors, and restore INTx emulation.
>
> Isn't INTx *emulation* a PCIe implementation detail?  Doesn't seem
> relevant to callers that it's emulated.

Don't know how the emulation ended up there. It restores INTx which is
obvioulsy not a wire on PCIe... But yes, it's uninteresting.

Re: [patch 27/39] PCI/MSI: Move pci_disable_msix() to api.c

[Bjorn Helgaas]

On Fri, Nov 11, 2022 at 02:54:58PM +0100, Thomas Gleixner wrote:
> From: Ahmed S. Darwish 
> 
> To distangle the maze in msi.c, all exported device-driver MSI APIs are
> now to be grouped in one file, api.c.
> 
> Move pci_disable_msix() and make its kernel-doc comprehensive.
> 
> Signed-off-by: Ahmed S. Darwish 
> Signed-off-by: Thomas Gleixner 

Acked-by: Bjorn Helgaas 

Trivial question below.

> ---
>  drivers/pci/msi/api.c | 24 
>  drivers/pci/msi/msi.c | 14 +-
>  drivers/pci/msi/msi.h |  1 +
>  3 files changed, 26 insertions(+), 13 deletions(-)
> ---
> diff --git a/drivers/pci/msi/api.c b/drivers/pci/msi/api.c
> index 83ea38ffa116..653a61868ae6 100644
> --- a/drivers/pci/msi/api.c
> +++ b/drivers/pci/msi/api.c
> @@ -112,6 +112,30 @@ int pci_enable_msix_range(struct pci_dev *dev, struct 
> msix_entry *entries,
>  EXPORT_SYMBOL(pci_enable_msix_range);
>  
>  /**
> + * pci_disable_msix() - Disable MSI-X interrupt mode on device
> + * @dev: the PCI device to operate on
> + *
> + * Legacy device driver API to disable MSI-X interrupt mode on device,
> + * free earlier-allocated interrupt vectors, and restore INTx emulation.

Isn't INTx *emulation* a PCIe implementation detail?  Doesn't seem
relevant to callers that it's emulated.

> + * The PCI device Linux IRQ (@dev->irq) is restored to its default pin
> + * assertion IRQ. This is the cleanup pair of pci_enable_msix_range().
> + *
> + * NOTE: The newer pci_alloc_irq_vectors() / pci_free_irq_vectors() API
> + * pair should, in general, be used instead.
> + */
> +void pci_disable_msix(struct pci_dev *dev)
> +{
> + if (!pci_msi_enabled() || !dev || !dev->msix_enabled)
> + return;
> +
> + msi_lock_descs(>dev);
> + pci_msix_shutdown(dev);
> + pci_free_msi_irqs(dev);
> + msi_unlock_descs(>dev);
> +}
> +EXPORT_SYMBOL(pci_disable_msix);
> +
> +/**
>   * pci_alloc_irq_vectors() - Allocate multiple device interrupt vectors
>   * @dev:  the PCI device to operate on
>   * @min_vecs: minimum required number of vectors (must be >= 1)
> diff --git a/drivers/pci/msi/msi.c b/drivers/pci/msi/msi.c
> index 1226d66da992..6fa90d07d2e4 100644
> --- a/drivers/pci/msi/msi.c
> +++ b/drivers/pci/msi/msi.c
> @@ -736,7 +736,7 @@ static int __pci_enable_msix(struct pci_dev *dev, struct 
> msix_entry *entries,
>   return msix_capability_init(dev, entries, nvec, affd);
>  }
>  
> -static void pci_msix_shutdown(struct pci_dev *dev)
> +void pci_msix_shutdown(struct pci_dev *dev)
>  {
>   struct msi_desc *desc;
>  
> @@ -758,18 +758,6 @@ static void pci_msix_shutdown(struct pci_dev *dev)
>   pcibios_alloc_irq(dev);
>  }
>  
> -void pci_disable_msix(struct pci_dev *dev)
> -{
> - if (!pci_msi_enable || !dev || !dev->msix_enabled)
> - return;
> -
> - msi_lock_descs(>dev);
> - pci_msix_shutdown(dev);
> - pci_free_msi_irqs(dev);
> - msi_unlock_descs(>dev);
> -}
> -EXPORT_SYMBOL(pci_disable_msix);
> -
>  int __pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec,
>  struct irq_affinity *affd)
>  {
> diff --git a/drivers/pci/msi/msi.h b/drivers/pci/msi/msi.h
> index 8c4a5289432d..77e2587f7e4f 100644
> --- a/drivers/pci/msi/msi.h
> +++ b/drivers/pci/msi/msi.h
> @@ -86,6 +86,7 @@ static inline __attribute_const__ u32 msi_multi_mask(struct 
> msi_desc *desc)
>  
>  /* MSI internal functions invoked from the public APIs */
>  void pci_msi_shutdown(struct pci_dev *dev);
> +void pci_msix_shutdown(struct pci_dev *dev);
>  void pci_free_msi_irqs(struct pci_dev *dev);
>  int __pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec, 
> struct irq_affinity *affd);
>  int __pci_enable_msix_range(struct pci_dev *dev, struct msix_entry *entries, 
> int minvec,
> 

[patch 27/39] PCI/MSI: Move pci_disable_msix() to api.c

[Thomas Gleixner]

From: Ahmed S. Darwish 

To distangle the maze in msi.c, all exported device-driver MSI APIs are
now to be grouped in one file, api.c.

Move pci_disable_msix() and make its kernel-doc comprehensive.

Signed-off-by: Ahmed S. Darwish 
Signed-off-by: Thomas Gleixner 

---
 drivers/pci/msi/api.c | 24 
 drivers/pci/msi/msi.c | 14 +-
 drivers/pci/msi/msi.h |  1 +
 3 files changed, 26 insertions(+), 13 deletions(-)
---
diff --git a/drivers/pci/msi/api.c b/drivers/pci/msi/api.c
index 83ea38ffa116..653a61868ae6 100644
--- a/drivers/pci/msi/api.c
+++ b/drivers/pci/msi/api.c
@@ -112,6 +112,30 @@ int pci_enable_msix_range(struct pci_dev *dev, struct 
msix_entry *entries,
 EXPORT_SYMBOL(pci_enable_msix_range);
 
 /**
+ * pci_disable_msix() - Disable MSI-X interrupt mode on device
+ * @dev: the PCI device to operate on
+ *
+ * Legacy device driver API to disable MSI-X interrupt mode on device,
+ * free earlier-allocated interrupt vectors, and restore INTx emulation.
+ * The PCI device Linux IRQ (@dev->irq) is restored to its default pin
+ * assertion IRQ. This is the cleanup pair of pci_enable_msix_range().
+ *
+ * NOTE: The newer pci_alloc_irq_vectors() / pci_free_irq_vectors() API
+ * pair should, in general, be used instead.
+ */
+void pci_disable_msix(struct pci_dev *dev)
+{
+   if (!pci_msi_enabled() || !dev || !dev->msix_enabled)
+   return;
+
+   msi_lock_descs(>dev);
+   pci_msix_shutdown(dev);
+   pci_free_msi_irqs(dev);
+   msi_unlock_descs(>dev);
+}
+EXPORT_SYMBOL(pci_disable_msix);
+
+/**
  * pci_alloc_irq_vectors() - Allocate multiple device interrupt vectors
  * @dev:  the PCI device to operate on
  * @min_vecs: minimum required number of vectors (must be >= 1)
diff --git a/drivers/pci/msi/msi.c b/drivers/pci/msi/msi.c
index 1226d66da992..6fa90d07d2e4 100644
--- a/drivers/pci/msi/msi.c
+++ b/drivers/pci/msi/msi.c
@@ -736,7 +736,7 @@ static int __pci_enable_msix(struct pci_dev *dev, struct 
msix_entry *entries,
return msix_capability_init(dev, entries, nvec, affd);
 }
 
-static void pci_msix_shutdown(struct pci_dev *dev)
+void pci_msix_shutdown(struct pci_dev *dev)
 {
struct msi_desc *desc;
 
@@ -758,18 +758,6 @@ static void pci_msix_shutdown(struct pci_dev *dev)
pcibios_alloc_irq(dev);
 }
 
-void pci_disable_msix(struct pci_dev *dev)
-{
-   if (!pci_msi_enable || !dev || !dev->msix_enabled)
-   return;
-
-   msi_lock_descs(>dev);
-   pci_msix_shutdown(dev);
-   pci_free_msi_irqs(dev);
-   msi_unlock_descs(>dev);
-}
-EXPORT_SYMBOL(pci_disable_msix);
-
 int __pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec,
   struct irq_affinity *affd)
 {
diff --git a/drivers/pci/msi/msi.h b/drivers/pci/msi/msi.h
index 8c4a5289432d..77e2587f7e4f 100644
--- a/drivers/pci/msi/msi.h
+++ b/drivers/pci/msi/msi.h
@@ -86,6 +86,7 @@ static inline __attribute_const__ u32 msi_multi_mask(struct 
msi_desc *desc)
 
 /* MSI internal functions invoked from the public APIs */
 void pci_msi_shutdown(struct pci_dev *dev);
+void pci_msix_shutdown(struct pci_dev *dev);
 void pci_free_msi_irqs(struct pci_dev *dev);
 int __pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec, struct 
irq_affinity *affd);
 int __pci_enable_msix_range(struct pci_dev *dev, struct msix_entry *entries, 
int minvec,