Commit 60290525 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

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: default avatarThomas Gleixner <tglx@linutronix.de>
Tested-by: default avatarMichael Kelley <mikelley@microsoft.com>
Tested-by: default avatarNishanth Menon <nm@ti.com>
Reviewed-by: default avatarJason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20211206210747.873833567@linutronix.de
parent 1046f71d

include/linux/msi.h

+2 −0
Original line number Diff line number Diff line
@@ -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);

kernel/irq/msi.c

+59 −0
Original line number Diff line number Diff line
@@ -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;