On Fri, Feb 19, 2021 at 03:40:05PM +0100, Robert Richter wrote:

On 18.02.21 23:04:55, Dejin Zheng wrote:

quoted

Introduce pcim_alloc_irq_vectors(), a device-managed version of
pci_alloc_irq_vectors(). Introducing this function can simplify
the error handling path in many drivers.

And use pci_free_irq_vectors() to replace some code in pcim_release(),
they are equivalent, and no functional change. It is more explicit
that pcim_alloc_irq_vectors() is a device-managed function.

Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Dejin Zheng <redacted>
---
v3 -> v4:
	- No change
v2 -> v3:
	- Add some commit comments for replace some codes in
	  pcim_release() by pci_free_irq_vectors().
v1 -> v2:
	- Use pci_free_irq_vectors() to replace some code in
	  pcim_release().
	- Modify some commit messages.

 drivers/pci/pci.c   | 33 +++++++++++++++++++++++++++++----
 include/linux/pci.h |  3 +++
 2 files changed, 32 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index b67c4327d307..db799d089c85 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c

@@ -1969,10 +1969,7 @@ static void pcim_release(struct device *gendev, void *res)
 	struct pci_devres *this = res;
 	int i;
 
-	if (dev->msi_enabled)
-		pci_disable_msi(dev);
-	if (dev->msix_enabled)
-		pci_disable_msix(dev);
+	pci_free_irq_vectors(dev);
 
 	for (i = 0; i < DEVICE_COUNT_RESOURCE; i++)
 		if (this->region_mask & (1 << i))

@@ -2054,6 +2051,34 @@ void pcim_pin_device(struct pci_dev *pdev)
 }
 EXPORT_SYMBOL(pcim_pin_device);
 
+/**
+ * pcim_alloc_irq_vectors - a device-managed pci_alloc_irq_vectors()
+ * @dev:		PCI device to operate on
+ * @min_vecs:		minimum number of vectors required (must be >= 1)
+ * @max_vecs:		maximum (desired) number of vectors
+ * @flags:		flags or quirks for the allocation
+ *
+ * Return the number of vectors allocated, (which might be smaller than
+ * @max_vecs) if successful, or a negative error code on error. If less
+ * than @min_vecs interrupt vectors are available for @dev the function
+ * will fail with -ENOSPC.
+ *
+ * It depends on calling pcim_enable_device() to make IRQ resources
+ * manageable.
+ */
+int pcim_alloc_irq_vectors(struct pci_dev *dev, unsigned int min_vecs,
+				unsigned int max_vecs, unsigned int flags)
+{
+	struct pci_devres *dr;
+
+	dr = find_pci_dr(dev);
+	if (!dr || !dr->enabled)
+		return -EINVAL;
+
+	return pci_alloc_irq_vectors(dev, min_vecs, max_vecs, flags);
+}
+EXPORT_SYMBOL(pcim_alloc_irq_vectors);

If it is just about having a pcim-* counterpart why not just an inline
function like the one below.

Robert and Andy,

First of all, thank you very much for your suggestions and help.
I think this is not just a pcim-* counterpart, I may not explain this
place clearly. In addition to calling pci_alloc_irq_vectors(), the
pcim_alloc_irq_vectors() function also checks whether the pci device is
enabled and whether the pci device resource has been managed. If any one
is wrong, it will return failure. Therefore, I think it should be used
as a function. For novices, maybe I understand it incorrectly, so I look
forward to your suggestions.

quoted

+	dr = find_pci_dr(dev);

static struct pci_devres *find_pci_dr(struct pci_dev *pdev)
{
        if (pci_is_managed(pdev))
                return devres_find(&pdev->dev, pcim_release, NULL, NULL);                                                         
        return NULL;
}
here checks whether the pci device resource has been managed.

quoted

+	if (!dr || !dr->enabled)

here checks whether the pci device is enabled.

int pcim_enable_device(struct pci_dev *pdev)
{
        struct pci_devres *dr;
        int rc;

        dr = get_pci_dr(pdev);
        if (unlikely(!dr))
                return -ENOMEM;
        if (dr->enabled)
                return 0;

        rc = pci_enable_device(pdev);
        if (!rc) {
                pdev->is_managed = 1;
                dr->enabled = 1;
        }
        return rc;
}

BR,
Dejin

quoted

+
 /*
  * pcibios_add_device - provide arch specific hooks when adding device dev
  * @dev: the PCI device being added

diff --git a/include/linux/pci.h b/include/linux/pci.h
index 86c799c97b77..d75ba85ddfc5 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h

@@ -1818,6 +1818,9 @@ pci_alloc_irq_vectors(struct pci_dev *dev, unsigned int min_vecs,
 					      NULL);
 }
 
+int pcim_alloc_irq_vectors(struct pci_dev *dev, unsigned int min_vecs,
+				unsigned int max_vecs, unsigned int flags);
+

static inline int pcim_alloc_irq_vectors(struct pci_dev *dev,
	unsigned int min_vecs, unsigned int max_vecs, unsigned int flags)
{
	if (!pci_is_managed(dev, min_vecs, max_vecs, flags))
		return -EINVAL;

	return pci_alloc_irq_vectors(dev, min_vecs, max_vecs, flags);
}

All those stub functions with EXPORT_SYMBOLS etc. could be dropped
then.

With some macro magic added a list of functions could easily being
created that are already managed but just need a pcim* counterpart.

-Robert

quoted

 /* Include architecture-dependent settings and functions */
 
 #include <asm/pci.h>
-- 
2.25.0