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linux-next/include/linux/ioasid.h
Jean-Philippe Brucker cb4789b0d1 iommu/ioasid: Add ioasid references
Let IOASID users take references to existing ioasids with ioasid_get().
ioasid_put() drops a reference and only frees the ioasid when its
reference number is zero. It returns true if the ioasid was freed.
For drivers that don't call ioasid_get(), ioasid_put() is the same as
ioasid_free().

Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/20201106155048.997886-2-jean-philippe@linaro.org
Signed-off-by: Will Deacon <will@kernel.org>
2020-11-23 14:16:55 +00:00

83 lines
2.1 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __LINUX_IOASID_H
#define __LINUX_IOASID_H
#include <linux/types.h>
#include <linux/errno.h>
#define INVALID_IOASID ((ioasid_t)-1)
typedef unsigned int ioasid_t;
typedef ioasid_t (*ioasid_alloc_fn_t)(ioasid_t min, ioasid_t max, void *data);
typedef void (*ioasid_free_fn_t)(ioasid_t ioasid, void *data);
struct ioasid_set {
int dummy;
};
/**
* struct ioasid_allocator_ops - IOASID allocator helper functions and data
*
* @alloc: helper function to allocate IOASID
* @free: helper function to free IOASID
* @list: for tracking ops that share helper functions but not data
* @pdata: data belong to the allocator, provided when calling alloc()
*/
struct ioasid_allocator_ops {
ioasid_alloc_fn_t alloc;
ioasid_free_fn_t free;
struct list_head list;
void *pdata;
};
#define DECLARE_IOASID_SET(name) struct ioasid_set name = { 0 }
#if IS_ENABLED(CONFIG_IOASID)
ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min, ioasid_t max,
void *private);
void ioasid_get(ioasid_t ioasid);
bool ioasid_put(ioasid_t ioasid);
void *ioasid_find(struct ioasid_set *set, ioasid_t ioasid,
bool (*getter)(void *));
int ioasid_register_allocator(struct ioasid_allocator_ops *allocator);
void ioasid_unregister_allocator(struct ioasid_allocator_ops *allocator);
int ioasid_set_data(ioasid_t ioasid, void *data);
#else /* !CONFIG_IOASID */
static inline ioasid_t ioasid_alloc(struct ioasid_set *set, ioasid_t min,
ioasid_t max, void *private)
{
return INVALID_IOASID;
}
static inline void ioasid_get(ioasid_t ioasid)
{
}
static inline bool ioasid_put(ioasid_t ioasid)
{
return false;
}
static inline void *ioasid_find(struct ioasid_set *set, ioasid_t ioasid,
bool (*getter)(void *))
{
return NULL;
}
static inline int ioasid_register_allocator(struct ioasid_allocator_ops *allocator)
{
return -ENOTSUPP;
}
static inline void ioasid_unregister_allocator(struct ioasid_allocator_ops *allocator)
{
}
static inline int ioasid_set_data(ioasid_t ioasid, void *data)
{
return -ENOTSUPP;
}
#endif /* CONFIG_IOASID */
#endif /* __LINUX_IOASID_H */