[PATCH v7 1/4] PCI: Introduce pcim_alloc_irq_vectors()

Dejin Zheng
2021-06-07T15:39:29Z

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.

When CONFIG_PCI=n, there is no stub for pci_is_managed(), but
pcim_alloc_irq_vectors() will use it, so add one like other similar stubs.
Otherwise there can be build errors, as here by kernel test robot
reported:
include/linux/pci.h: In function 'pcim_alloc_irq_vectors':
>> include/linux/pci.h:1847:7: error: implicit declaration of function 'pci_is_managed' [-Werror=implicit-function-declaration]
1847 | if (!pci_is_managed(dev))
| ^~~~~~~~~~~~~~

Reported-by: kernel test robot <lkp@intel.com>
Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Robert Richter <rric@kernel.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Dejin Zheng <zhengdejin5@gmail.com>
---
v6 -> v7:
- rebase to PCI next branch
- add a stub for pci_is_managed() when disable PCI for
fix build error in sparc architecture.
v5 -> v6:
- rebase to 5.13-rc4
v4 -> v5:
- Remove the check of enable device in pcim_alloc_irq_vectors()
and make it as a static line function.
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 | 5 +----
include/linux/pci.h | 25 +++++++++++++++++++++++++
2 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 452351025a09..e3b3fc59bd35 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1989,10 +1989,7 @@ 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))
diff --git a/include/linux/pci.h b/include/linux/pci.h
index c20211e59a57..5783262c4643 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1730,6 +1730,7 @@ static inline struct pci_dev *pci_get_class(unsigned int class,

static inline void pci_set_master(struct pci_dev *dev) { }
static inline int pci_enable_device(struct pci_dev *dev) { return -EIO; }
+static inline int pci_is_managed(struct pci_dev *pdev) { return 0; }
static inline void pci_disable_device(struct pci_dev *dev) { }
static inline int pcim_enable_device(struct pci_dev *pdev) { return -EIO; }
static inline int pci_assign_resource(struct pci_dev *dev, int i)
@@ -1825,6 +1826,30 @@ pci_alloc_irq_vectors(struct pci_dev *dev, unsigned int min_vecs,
NULL);
}

+/**
+ * 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.
+ */
+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))
+ return -EINVAL;
+ return pci_alloc_irq_vectors(dev, min_vecs, max_vecs, flags);
+}
+
/* Include architecture-dependent settings and functions */

#include <asm/pci.h>
--
2.30.1