Clients of the ida API routinely follow the same steps to allocate and ida index, as well as to free said index. These helper routines should make it a little easier to use these APIs.
Signed-off-by: Lee Duncan <[email protected]> --- include/linux/idr.h | 42 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) diff --git a/include/linux/idr.h b/include/linux/idr.h index 013fd9bc4cb6..5a9526dc6298 100644 --- a/include/linux/idr.h +++ b/include/linux/idr.h @@ -16,6 +16,8 @@ #include <linux/bitops.h> #include <linux/init.h> #include <linux/rcupdate.h> +#include <linux/spinlock.h> +#include <linux/gfp.h> /* * We want shallower trees and thus more bits covered at each layer. 8 @@ -183,4 +185,44 @@ static inline int ida_get_new(struct ida *ida, int *p_id) void __init idr_init_cache(void); +/** + * ida_get_index - allocate a ida index value + * @ida idr handle + * @lock spinlock handle protecting this index + * @p_id pointer to allocated index value + * + * A helper function for safely allocating an index value (id), + * returning a negative errno value on failure, else 0. + */ +static inline int ida_get_index(struct ida *ida, spinlock_t *lock, int *p_id) +{ + int error = -ENOMEM; + + do { + if (!ida_pre_get(ida, GFP_KERNEL)) + break; + spin_lock(lock); + error = ida_get_new(ida, p_id); + spin_unlock(lock); + } while (error == -EAGAIN); + + return error; +} + +/** + * ida_put_index - free an allocated ida index value + * @ida idr handle + * @lock spinlock handle protecting this index + * @id the value of the allocated index + * + * A helper function that goes with @ida_get_index, which safely + * frees a previously-allocated index value. + */ +static inline void ida_put_index(struct ida *ida, spinlock_t *lock, int id) +{ + spin_lock(lock); + ida_remove(ida, id); + spin_unlock(lock); +} + #endif /* __IDR_H__ */ -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
