On Tue, Mar 11 2025 at 18:10, Jonathan Cameron wrote:
> On Sun, 9 Mar 2025 09:41:49 +0100 (CET)
> Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
>
> This one runs into some of the stuff that the docs say
> to not do. I don't there there are bugs in here as such
> but it gets harder to reason about and fragile in the long
> run. Easy enough to avoid though - see inline.
Right. Updated variant below.
Thanks,
tglx
---
--- a/drivers/pci/msi/api.c
+++ b/drivers/pci/msi/api.c
@@ -53,10 +53,9 @@ void pci_disable_msi(struct pci_dev *dev
if (!pci_msi_enabled() || !dev || !dev->msi_enabled)
return;
- msi_lock_descs(&dev->dev);
+ guard(msi_descs_lock)(&dev->dev);
pci_msi_shutdown(dev);
pci_free_msi_irqs(dev);
- msi_unlock_descs(&dev->dev);
}
EXPORT_SYMBOL(pci_disable_msi);
@@ -196,10 +195,9 @@ void pci_disable_msix(struct pci_dev *de
if (!pci_msi_enabled() || !dev || !dev->msix_enabled)
return;
- msi_lock_descs(&dev->dev);
+ guard(msi_descs_lock)(&dev->dev);
pci_msix_shutdown(dev);
pci_free_msi_irqs(dev);
- msi_unlock_descs(&dev->dev);
}
EXPORT_SYMBOL(pci_disable_msix);
--- a/drivers/pci/msi/msi.c
+++ b/drivers/pci/msi/msi.c
@@ -336,41 +336,11 @@ 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)
{
- struct irq_affinity_desc *masks = NULL;
+ 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, but mark it enabled
- * so that setup code can evaluate it.
- */
- pci_msi_set_enable(dev, 0);
- dev->msi_enabled = 1;
-
- if (affd)
- masks = irq_create_affinity_masks(nvec, affd);
- msi_lock_descs(&dev->dev);
- ret = msi_setup_msi_desc(dev, nvec, masks);
if (ret)
goto fail;
@@ -399,19 +369,48 @@ 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);
fail:
dev->msi_enabled = 0;
-unlock:
- msi_unlock_descs(&dev->dev);
- kfree(masks);
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);
+ dev->msi_enabled = 1;
+
+ 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)
{
@@ -666,37 +665,37 @@ static void msix_mask_all(void __iomem *
writel(ctrl, base + PCI_MSIX_ENTRY_VECTOR_CTRL);
}
-static int msix_setup_interrupts(struct pci_dev *dev, struct msix_entry *entries,
- int nvec, struct irq_affinity *affd)
+static int __msix_setup_interrupts(struct pci_dev *dev, struct msix_entry *entries,
+ int nvec, struct irq_affinity_desc *masks)
{
- struct irq_affinity_desc *masks = NULL;
- int ret;
+ int ret = msix_setup_msi_descs(dev, entries, nvec, masks);
- if (affd)
- masks = irq_create_affinity_masks(nvec, affd);
-
- msi_lock_descs(&dev->dev);
- ret = msix_setup_msi_descs(dev, entries, nvec, masks);
if (ret)
- goto out_free;
+ return ret;
ret = pci_msi_setup_msi_irqs(dev, nvec, PCI_CAP_ID_MSIX);
if (ret)
- goto out_free;
+ return ret;
/* Check if all MSI entries honor device restrictions */
ret = msi_verify_entries(dev);
if (ret)
- goto out_free;
+ return ret;
msix_update_entries(dev, entries);
- goto out_unlock;
+ return 0;
+}
-out_free:
- pci_free_msi_irqs(dev);
-out_unlock:
- msi_unlock_descs(&dev->dev);
- kfree(masks);
+static int msix_setup_interrupts(struct pci_dev *dev, struct msix_entry *entries,
+ int nvec, struct irq_affinity *affd)
+{
+ struct irq_affinity_desc *masks __free(kfree) =
+ affd ? irq_create_affinity_masks(nvec, affd) : NULL;
+
+ guard(msi_descs_lock)(&dev->dev);
+ int ret = __msix_setup_interrupts(dev, entries, nvec, masks);
+ if (ret)
+ pci_free_msi_irqs(dev);
return ret;
}
@@ -871,13 +870,13 @@ void __pci_restore_msix_state(struct pci
write_msg = arch_restore_msi_irqs(dev);
- msi_lock_descs(&dev->dev);
- msi_for_each_desc(entry, &dev->dev, MSI_DESC_ALL) {
- if (write_msg)
- __pci_write_msi_msg(entry, &entry->msg);
- pci_msix_write_vector_ctrl(entry, entry->pci.msix_ctrl);
+ scoped_guard (msi_descs_lock, &dev->dev) {
+ msi_for_each_desc(entry, &dev->dev, MSI_DESC_ALL) {
+ if (write_msg)
+ __pci_write_msi_msg(entry, &entry->msg);
+ pci_msix_write_vector_ctrl(entry, entry->pci.msix_ctrl);
+ }
}
- msi_unlock_descs(&dev->dev);
pci_msix_clear_and_set_ctrl(dev, PCI_MSIX_FLAGS_MASKALL, 0);
}
