diff --git a/include/linux/msi.h b/include/linux/msi.h index 69c588efe85b..703221f7e9ea 100644 --- a/include/linux/msi.h +++ b/include/linux/msi.h @@ -140,6 +140,18 @@ struct msi_desc { struct pci_msi_desc pci; }; +/* + * Filter values for the MSI descriptor iterators and accessor functions. + */ +enum msi_desc_filter { + /* All descriptors */ + MSI_DESC_ALL, + /* Descriptors which have no interrupt associated */ + MSI_DESC_NOTASSOCIATED, + /* Descriptors which have an interrupt associated */ + MSI_DESC_ASSOCIATED, +}; + /** * msi_device_data - MSI per device data * @properties: MSI properties which are interesting to drivers @@ -147,6 +159,7 @@ struct msi_desc { * @platform_data: Platform-MSI specific data * @list: List of MSI descriptors associated to the device * @mutex: Mutex protecting the MSI list + * @__next: Cached pointer to the next entry for iterators */ struct msi_device_data { unsigned long properties; @@ -154,6 +167,7 @@ struct msi_device_data { struct platform_msi_priv_data *platform_data; struct list_head list; struct mutex mutex; + struct msi_desc *__next; }; int msi_setup_device_data(struct device *dev); @@ -162,6 +176,25 @@ unsigned int msi_get_virq(struct device *dev, unsigned int index); void msi_lock_descs(struct device *dev); void msi_unlock_descs(struct device *dev); +struct msi_desc *msi_first_desc(struct device *dev, enum msi_desc_filter filter); +struct msi_desc *msi_next_desc(struct device *dev, enum msi_desc_filter filter); + +/** + * msi_for_each_desc - Iterate the MSI descriptors + * + * @desc: struct msi_desc pointer used as iterator + * @dev: struct device pointer - device to iterate + * @filter: Filter for descriptor selection + * + * Notes: + * - The loop must be protected with a msi_lock_descs()/msi_unlock_descs() + * pair. + * - It is safe to remove a retrieved MSI descriptor in the loop. + */ +#define msi_for_each_desc(desc, dev, filter) \ + for ((desc) = msi_first_desc((dev), (filter)); (desc); \ + (desc) = msi_next_desc((dev), (filter))) + /* Helpers to hide struct msi_desc implementation details */ #define msi_desc_to_dev(desc) ((desc)->dev) #define dev_to_msi_list(dev) (&(dev)->msi.data->list) diff --git a/kernel/irq/msi.c b/kernel/irq/msi.c index 3b21e99bb793..bc67b2cafc9d 100644 --- a/kernel/irq/msi.c +++ b/kernel/irq/msi.c @@ -125,10 +125,106 @@ EXPORT_SYMBOL_GPL(msi_lock_descs); */ void msi_unlock_descs(struct device *dev) { + /* Clear the next pointer which was cached by the iterator */ + dev->msi.data->__next = NULL; mutex_unlock(&dev->msi.data->mutex); } EXPORT_SYMBOL_GPL(msi_unlock_descs); +static bool msi_desc_match(struct msi_desc *desc, enum msi_desc_filter filter) +{ + switch (filter) { + case MSI_DESC_ALL: + return true; + case MSI_DESC_NOTASSOCIATED: + return !desc->irq; + case MSI_DESC_ASSOCIATED: + return !!desc->irq; + } + WARN_ON_ONCE(1); + return false; +} + +static struct msi_desc *msi_find_first_desc(struct device *dev, enum msi_desc_filter filter) +{ + struct msi_desc *desc; + + list_for_each_entry(desc, dev_to_msi_list(dev), list) { + if (msi_desc_match(desc, filter)) + return desc; + } + return NULL; +} + +/** + * msi_first_desc - Get the first MSI descriptor of a device + * @dev: Device to operate on + * @filter: Descriptor state filter + * + * Must be called with the MSI descriptor mutex held, i.e. msi_lock_descs() + * must be invoked before the call. + * + * Return: Pointer to the first MSI descriptor matching the search + * criteria, NULL if none found. + */ +struct msi_desc *msi_first_desc(struct device *dev, enum msi_desc_filter filter) +{ + struct msi_desc *desc; + + if (WARN_ON_ONCE(!dev->msi.data)) + return NULL; + + lockdep_assert_held(&dev->msi.data->mutex); + + desc = msi_find_first_desc(dev, filter); + dev->msi.data->__next = desc ? list_next_entry(desc, list) : NULL; + return desc; +} +EXPORT_SYMBOL_GPL(msi_first_desc); + +static struct msi_desc *__msi_next_desc(struct device *dev, enum msi_desc_filter filter, + struct msi_desc *from) +{ + struct msi_desc *desc = from; + + list_for_each_entry_from(desc, dev_to_msi_list(dev), list) { + if (msi_desc_match(desc, filter)) + return desc; + } + return NULL; +} + +/** + * msi_next_desc - Get the next MSI descriptor of a device + * @dev: Device to operate on + * + * The first invocation of msi_next_desc() has to be preceeded by a + * successful incovation of __msi_first_desc(). Consecutive invocations are + * only valid if the previous one was successful. All these operations have + * to be done within the same MSI mutex held region. + * + * Return: Pointer to the next MSI descriptor matching the search + * criteria, NULL if none found. + */ +struct msi_desc *msi_next_desc(struct device *dev, enum msi_desc_filter filter) +{ + struct msi_device_data *data = dev->msi.data; + struct msi_desc *desc; + + if (WARN_ON_ONCE(!data)) + return NULL; + + lockdep_assert_held(&data->mutex); + + if (!data->__next) + return NULL; + + desc = __msi_next_desc(dev, filter, data->__next); + dev->msi.data->__next = desc ? list_next_entry(desc, list) : NULL; + return desc; +} +EXPORT_SYMBOL_GPL(msi_next_desc); + /** * msi_get_virq - Return Linux interrupt number of a MSI interrupt * @dev: Device to operate on