[PATCH v2 1/4] PCI: Introduce pcim_alloc_irq_vectors()

Dejin Zheng
2021-02-16T14:19:15Z

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.

Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Dejin Zheng <zhengdejin5@gmail.com>
---
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);
+
/*
* 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);
+
/* Include architecture-dependent settings and functions */

#include <asm/pci.h>
--
2.25.0