diff options
author | Thomas Gleixner <tglx@linutronix.de> | 2021-12-07 01:51:08 +0300 |
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committer | Thomas Gleixner <tglx@linutronix.de> | 2021-12-17 00:22:17 +0300 |
commit | 1046f71d7268b1680d7b044dea83c664403f6302 (patch) | |
tree | 62eda7a479602d007d6e3d12d4d9ba39e3e07b72 /kernel/irq/msi.c | |
parent | 0f62d941acf9ac3b6025692ce649b1f282b89e7f (diff) | |
download | linux-1046f71d7268b1680d7b044dea83c664403f6302.tar.xz |
genirq/msi: Provide a set of advanced MSI accessors and iterators
In preparation for dynamic handling of MSI-X interrupts provide a new set
of MSI descriptor accessor functions and iterators. They are benefitial per
se as they allow to cleanup quite some code in various MSI domain
implementations.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Tested-by: Nishanth Menon <nm@ti.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20211206210747.818635078@linutronix.de
Diffstat (limited to 'kernel/irq/msi.c')
-rw-r--r-- | kernel/irq/msi.c | 96 |
1 files changed, 96 insertions, 0 deletions
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 |