Re: [patch 32/39] PCI/MSI: Reorder functions in msi.c
On Wed, Nov 16 2022 at 10:28, Bjorn Helgaas wrote: > On Fri, Nov 11, 2022 at 02:55:06PM +0100, Thomas Gleixner wrote: >> From: Ahmed S. Darwish >> >> There is no way to navigate msi.c without banging the head against the wall >> every now and then because MSI and MSI-X specific functions are >> intermingled and the code flow is completely non-obvious. >> >> Reorder everthing so common helpers, MSI and MSI-X specific functions are >> grouped together. > > s/everthing/everything/ > >> Suggested-by: Thomas Gleixner >> Signed-off-by: Ahmed S. Darwish >> Signed-off-by: Thomas Gleixner > > Acked-by: Bjorn Helgaas > > I assume this is pure code movement, so I didn't even look at the > text below. It is.
Re: [patch 32/39] PCI/MSI: Reorder functions in msi.c
On Fri, Nov 11, 2022 at 02:55:06PM +0100, Thomas Gleixner wrote:
> From: Ahmed S. Darwish
>
> There is no way to navigate msi.c without banging the head against the wall
> every now and then because MSI and MSI-X specific functions are
> intermingled and the code flow is completely non-obvious.
>
> Reorder everthing so common helpers, MSI and MSI-X specific functions are
> grouped together.
s/everthing/everything/
> Suggested-by: Thomas Gleixner
> Signed-off-by: Ahmed S. Darwish
> Signed-off-by: Thomas Gleixner
Acked-by: Bjorn Helgaas
I assume this is pure code movement, so I didn't even look at the
text below.
> ---
> drivers/pci/msi/msi.c | 577
> +-
> 1 file changed, 295 insertions(+), 282 deletions(-)
>
> --- a/drivers/pci/msi/msi.c
> +++ b/drivers/pci/msi/msi.c
> @@ -16,6 +16,97 @@
> int pci_msi_enable = 1;
> int pci_msi_ignore_mask;
>
> +/**
> + * pci_msi_supported - check whether MSI may be enabled on a device
> + * @dev: pointer to the pci_dev data structure of MSI device function
> + * @nvec: how many MSIs have been requested?
> + *
> + * Look at global flags, the device itself, and its parent buses
> + * to determine if MSI/-X are supported for the device. If MSI/-X is
> + * supported return 1, else return 0.
> + **/
> +static int pci_msi_supported(struct pci_dev *dev, int nvec)
> +{
> + struct pci_bus *bus;
> +
> + /* MSI must be globally enabled and supported by the device */
> + if (!pci_msi_enable)
> + return 0;
> +
> + if (!dev || dev->no_msi)
> + return 0;
> +
> + /*
> + * You can't ask to have 0 or less MSIs configured.
> + * a) it's stupid ..
> + * b) the list manipulation code assumes nvec >= 1.
> + */
> + if (nvec < 1)
> + return 0;
> +
> + /*
> + * Any bridge which does NOT route MSI transactions from its
> + * secondary bus to its primary bus must set NO_MSI flag on
> + * the secondary pci_bus.
> + *
> + * The NO_MSI flag can either be set directly by:
> + * - arch-specific PCI host bus controller drivers (deprecated)
> + * - quirks for specific PCI bridges
> + *
> + * or indirectly by platform-specific PCI host bridge drivers by
> + * advertising the 'msi_domain' property, which results in
> + * the NO_MSI flag when no MSI domain is found for this bridge
> + * at probe time.
> + */
> + for (bus = dev->bus; bus; bus = bus->parent)
> + if (bus->bus_flags & PCI_BUS_FLAGS_NO_MSI)
> + return 0;
> +
> + return 1;
> +}
> +
> +static void pcim_msi_release(void *pcidev)
> +{
> + struct pci_dev *dev = pcidev;
> +
> + dev->is_msi_managed = false;
> + pci_free_irq_vectors(dev);
> +}
> +
> +/*
> + * Needs to be separate from pcim_release to prevent an ordering problem
> + * vs. msi_device_data_release() in the MSI core code.
> + */
> +static int pcim_setup_msi_release(struct pci_dev *dev)
> +{
> + int ret;
> +
> + if (!pci_is_managed(dev) || dev->is_msi_managed)
> + return 0;
> +
> + ret = devm_add_action(>dev, pcim_msi_release, dev);
> + if (!ret)
> + dev->is_msi_managed = true;
> + return ret;
> +}
> +
> +/*
> + * Ordering vs. devres: msi device data has to be installed first so that
> + * pcim_msi_release() is invoked before it on device release.
> + */
> +static int pci_setup_msi_context(struct pci_dev *dev)
> +{
> + int ret = msi_setup_device_data(>dev);
> +
> + if (!ret)
> + ret = pcim_setup_msi_release(dev);
> + return ret;
> +}
> +
> +/*
> + * Helper functions for mask/unmask and MSI message handling
> + */
> +
> void pci_msi_update_mask(struct msi_desc *desc, u32 clear, u32 set)
> {
> raw_spinlock_t *lock = _pci_dev(desc->dev)->msi_lock;
> @@ -163,15 +254,8 @@ void pci_write_msi_msg(unsigned int irq,
> }
> EXPORT_SYMBOL_GPL(pci_write_msi_msg);
>
> -void pci_free_msi_irqs(struct pci_dev *dev)
> -{
> - pci_msi_teardown_msi_irqs(dev);
>
> - if (dev->msix_base) {
> - iounmap(dev->msix_base);
> - dev->msix_base = NULL;
> - }
> -}
> +/* PCI/MSI specific functionality */
>
> static void pci_intx_for_msi(struct pci_dev *dev, int enable)
> {
> @@ -190,111 +274,6 @@ static void pci_msi_set_enable(struct pc
> pci_write_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, control);
> }
>
> -/*
> - * Architecture override returns true when the PCI MSI message should be
> - * written by the generic restore function.
> - */
> -bool __weak arch_restore_msi_irqs(struct pci_dev *dev)
> -{
> - return true;
> -}
> -
> -void __pci_restore_msi_state(struct pci_dev *dev)
> -{
> - struct msi_desc *entry;
> - u16 control;
> -
> - if (!dev->msi_enabled)
> - return;
> -
> - entry = irq_get_msi_desc(dev->irq);
> -
> - pci_intx_for_msi(dev, 0);
> - pci_msi_set_enable(dev, 0);
> - if
[patch 32/39] PCI/MSI: Reorder functions in msi.c
From: Ahmed S. Darwish
There is no way to navigate msi.c without banging the head against the wall
every now and then because MSI and MSI-X specific functions are
intermingled and the code flow is completely non-obvious.
Reorder everthing so common helpers, MSI and MSI-X specific functions are
grouped together.
Suggested-by: Thomas Gleixner
Signed-off-by: Ahmed S. Darwish
Signed-off-by: Thomas Gleixner
---
drivers/pci/msi/msi.c | 577 +-
1 file changed, 295 insertions(+), 282 deletions(-)
--- a/drivers/pci/msi/msi.c
+++ b/drivers/pci/msi/msi.c
@@ -16,6 +16,97 @@
int pci_msi_enable = 1;
int pci_msi_ignore_mask;
+/**
+ * pci_msi_supported - check whether MSI may be enabled on a device
+ * @dev: pointer to the pci_dev data structure of MSI device function
+ * @nvec: how many MSIs have been requested?
+ *
+ * Look at global flags, the device itself, and its parent buses
+ * to determine if MSI/-X are supported for the device. If MSI/-X is
+ * supported return 1, else return 0.
+ **/
+static int pci_msi_supported(struct pci_dev *dev, int nvec)
+{
+ struct pci_bus *bus;
+
+ /* MSI must be globally enabled and supported by the device */
+ if (!pci_msi_enable)
+ return 0;
+
+ if (!dev || dev->no_msi)
+ return 0;
+
+ /*
+* You can't ask to have 0 or less MSIs configured.
+* a) it's stupid ..
+* b) the list manipulation code assumes nvec >= 1.
+*/
+ if (nvec < 1)
+ return 0;
+
+ /*
+* Any bridge which does NOT route MSI transactions from its
+* secondary bus to its primary bus must set NO_MSI flag on
+* the secondary pci_bus.
+*
+* The NO_MSI flag can either be set directly by:
+* - arch-specific PCI host bus controller drivers (deprecated)
+* - quirks for specific PCI bridges
+*
+* or indirectly by platform-specific PCI host bridge drivers by
+* advertising the 'msi_domain' property, which results in
+* the NO_MSI flag when no MSI domain is found for this bridge
+* at probe time.
+*/
+ for (bus = dev->bus; bus; bus = bus->parent)
+ if (bus->bus_flags & PCI_BUS_FLAGS_NO_MSI)
+ return 0;
+
+ return 1;
+}
+
+static void pcim_msi_release(void *pcidev)
+{
+ struct pci_dev *dev = pcidev;
+
+ dev->is_msi_managed = false;
+ pci_free_irq_vectors(dev);
+}
+
+/*
+ * Needs to be separate from pcim_release to prevent an ordering problem
+ * vs. msi_device_data_release() in the MSI core code.
+ */
+static int pcim_setup_msi_release(struct pci_dev *dev)
+{
+ int ret;
+
+ if (!pci_is_managed(dev) || dev->is_msi_managed)
+ return 0;
+
+ ret = devm_add_action(>dev, pcim_msi_release, dev);
+ if (!ret)
+ dev->is_msi_managed = true;
+ return ret;
+}
+
+/*
+ * Ordering vs. devres: msi device data has to be installed first so that
+ * pcim_msi_release() is invoked before it on device release.
+ */
+static int pci_setup_msi_context(struct pci_dev *dev)
+{
+ int ret = msi_setup_device_data(>dev);
+
+ if (!ret)
+ ret = pcim_setup_msi_release(dev);
+ return ret;
+}
+
+/*
+ * Helper functions for mask/unmask and MSI message handling
+ */
+
void pci_msi_update_mask(struct msi_desc *desc, u32 clear, u32 set)
{
raw_spinlock_t *lock = _pci_dev(desc->dev)->msi_lock;
@@ -163,15 +254,8 @@ void pci_write_msi_msg(unsigned int irq,
}
EXPORT_SYMBOL_GPL(pci_write_msi_msg);
-void pci_free_msi_irqs(struct pci_dev *dev)
-{
- pci_msi_teardown_msi_irqs(dev);
- if (dev->msix_base) {
- iounmap(dev->msix_base);
- dev->msix_base = NULL;
- }
-}
+/* PCI/MSI specific functionality */
static void pci_intx_for_msi(struct pci_dev *dev, int enable)
{
@@ -190,111 +274,6 @@ static void pci_msi_set_enable(struct pc
pci_write_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, control);
}
-/*
- * Architecture override returns true when the PCI MSI message should be
- * written by the generic restore function.
- */
-bool __weak arch_restore_msi_irqs(struct pci_dev *dev)
-{
- return true;
-}
-
-void __pci_restore_msi_state(struct pci_dev *dev)
-{
- struct msi_desc *entry;
- u16 control;
-
- if (!dev->msi_enabled)
- return;
-
- entry = irq_get_msi_desc(dev->irq);
-
- pci_intx_for_msi(dev, 0);
- pci_msi_set_enable(dev, 0);
- if (arch_restore_msi_irqs(dev))
- __pci_write_msi_msg(entry, >msg);
-
- pci_read_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, );
- pci_msi_update_mask(entry, 0, 0);
- control &= ~PCI_MSI_FLAGS_QSIZE;
- control |= (entry->pci.msi_attrib.multiple << 4) | PCI_MSI_FLAGS_ENABLE;
- pci_write_config_word(dev, dev->msi_cap + PCI_MSI_FLAGS, control);
-}
-
