[patch V4 08/14] PCI/MSI: Switch msi_capability_init() to guard(msi_desc_lock)

Thomas Gleixner
2025-03-19T10:56:54Z

Split the lock protected functionality of msi_capability_init() out into a
helper function and use guard(msi_desc_lock) to replace the lock/unlock
pair.

No functional change intended.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
V4: Split out from the previous combo patch
---
drivers/pci/msi/msi.c | 68 ++++++++++++++++++++++++++------------------------
1 file changed, 36 insertions(+), 32 deletions(-)

--- a/drivers/pci/msi/msi.c
+++ b/drivers/pci/msi/msi.c
@@ -336,38 +336,13 @@ static int msi_verify_entries(struct pci
return !entry ? 0 : -EIO;
}

-/**
- * msi_capability_init - configure device's MSI capability structure
- * @dev: pointer to the pci_dev data structure of MSI device function
- * @nvec: number of interrupts to allocate
- * @affd: description of automatic IRQ affinity assignments (may be %NULL)
- *
- * Setup the MSI capability structure of the device with the requested
- * number of interrupts. A return value of zero indicates the successful
- * setup of an entry with the new MSI IRQ. A negative return value indicates
- * an error, and a positive return value indicates the number of interrupts
- * which could have been allocated.
- */
-static int msi_capability_init(struct pci_dev *dev, int nvec,
- struct irq_affinity *affd)
+static int __msi_capability_init(struct pci_dev *dev, int nvec, struct irq_affinity_desc *masks)
{
+ int ret = msi_setup_msi_desc(dev, nvec, masks);
struct msi_desc *entry, desc;
- int ret;
-
- /* Reject multi-MSI early on irq domain enabled architectures */
- if (nvec > 1 && !pci_msi_domain_supports(dev, MSI_FLAG_MULTI_PCI_MSI, ALLOW_LEGACY))
- return 1;
-
- /* Disable MSI during setup in the hardware to erase stale state */
- pci_msi_set_enable(dev, 0);

- struct irq_affinity_desc *masks __free(kfree) =
- affd ? irq_create_affinity_masks(nvec, affd) : NULL;
-
- msi_lock_descs(&dev->dev);
- ret = msi_setup_msi_desc(dev, nvec, masks);
if (ret)
- goto unlock;
+ return ret;

/* All MSIs are unmasked by default; mask them all */
entry = msi_first_desc(&dev->dev, MSI_DESC_ALL);
@@ -395,16 +370,45 @@ static int msi_capability_init(struct pc

pcibios_free_irq(dev);
dev->irq = entry->irq;
- goto unlock;
-
+ return 0;
err:
pci_msi_unmask(&desc, msi_multi_mask(&desc));
pci_free_msi_irqs(dev);
-unlock:
- msi_unlock_descs(&dev->dev);
return ret;
}

+/**
+ * msi_capability_init - configure device's MSI capability structure
+ * @dev: pointer to the pci_dev data structure of MSI device function
+ * @nvec: number of interrupts to allocate
+ * @affd: description of automatic IRQ affinity assignments (may be %NULL)
+ *
+ * Setup the MSI capability structure of the device with the requested
+ * number of interrupts. A return value of zero indicates the successful
+ * setup of an entry with the new MSI IRQ. A negative return value indicates
+ * an error, and a positive return value indicates the number of interrupts
+ * which could have been allocated.
+ */
+static int msi_capability_init(struct pci_dev *dev, int nvec,
+ struct irq_affinity *affd)
+{
+ /* Reject multi-MSI early on irq domain enabled architectures */
+ if (nvec > 1 && !pci_msi_domain_supports(dev, MSI_FLAG_MULTI_PCI_MSI, ALLOW_LEGACY))
+ return 1;
+
+ /*
+ * Disable MSI during setup in the hardware, but mark it enabled
+ * so that setup code can evaluate it.
+ */
+ pci_msi_set_enable(dev, 0);
+
+ struct irq_affinity_desc *masks __free(kfree) =
+ affd ? irq_create_affinity_masks(nvec, affd) : NULL;
+
+ guard(msi_descs_lock)(&dev->dev);
+ return __msi_capability_init(dev, nvec, masks);
+}
+
int __pci_enable_msi_range(struct pci_dev *dev, int minvec, int maxvec,
struct irq_affinity *affd)
{