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genirq/msi: Provide msi_alloc_msi_desc() and a simple allocator 

Provide msi_alloc_msi_desc() which takes a template MSI descriptor for
initializing a newly allocated descriptor. This allows to simplify various
usage sites of alloc_msi_entry() and moves the storage handling into the
core code.

For simple cases where only a linear vector space is required provide
msi_add_simple_msi_descs() which just allocates a linear range of MSI
descriptors and fills msi_desc::msi_index accordingly.

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/20211206210747.873833567@linutronix.de
This commit is contained in:
Thomas Gleixner 2021-12-06 23:51:10 +01:00
parent 1046f71d72
commit 6029052536
2 changed files with 61 additions and 0 deletions
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2
include/linux/msi.h
View File

@ -247,6 +247,8 @@ static inline void pci_write_msi_msg(unsigned int irq, struct msi_msg *msg)
}
#endif /* CONFIG_PCI_MSI */
int msi_add_msi_desc(struct device *dev, struct msi_desc *init_desc);
struct msi_desc *alloc_msi_entry(struct device *dev, int nvec,
const struct irq_affinity_desc *affinity);
void free_msi_entry(struct msi_desc *entry);

59
kernel/irq/msi.c
View File

@ -60,6 +60,65 @@ void free_msi_entry(struct msi_desc *entry)
kfree(entry);
}
/**
* msi_add_msi_desc - Allocate and initialize a MSI descriptor
* @dev: Pointer to the device for which the descriptor is allocated
* @init_desc: Pointer to an MSI descriptor to initialize the new descriptor
*
* Return: 0 on success or an appropriate failure code.
*/
int msi_add_msi_desc(struct device *dev, struct msi_desc *init_desc)
{
struct msi_desc *desc;
lockdep_assert_held(&dev->msi.data->mutex);
desc = alloc_msi_entry(dev, init_desc->nvec_used, init_desc->affinity);
if (!desc)
return -ENOMEM;
/* Copy the MSI index and type specific data to the new descriptor. */
desc->msi_index = init_desc->msi_index;
desc->pci = init_desc->pci;
list_add_tail(&desc->list, &dev->msi.data->list);
return 0;
}
/**
* msi_add_simple_msi_descs - Allocate and initialize MSI descriptors
* @dev: Pointer to the device for which the descriptors are allocated
* @index: Index for the first MSI descriptor
* @ndesc: Number of descriptors to allocate
*
* Return: 0 on success or an appropriate failure code.
*/
static int msi_add_simple_msi_descs(struct device *dev, unsigned int index, unsigned int ndesc)
{
struct msi_desc *desc, *tmp;
LIST_HEAD(list);
unsigned int i;
lockdep_assert_held(&dev->msi.data->mutex);
for (i = 0; i < ndesc; i++) {
desc = alloc_msi_entry(dev, 1, NULL);
if (!desc)
goto fail;
desc->msi_index = index + i;
list_add_tail(&desc->list, &list);
}
list_splice_tail(&list, &dev->msi.data->list);
return 0;
fail:
list_for_each_entry_safe(desc, tmp, &list, list) {
list_del(&desc->list);
free_msi_entry(desc);
}
return -ENOMEM;
}
void __get_cached_msi_msg(struct msi_desc *entry, struct msi_msg *msg)
{
*msg = entry->msg;