IDR_ALLOC(9)                      Basic Kernel Library Functions                     IDR_ALLOC(9)



NAME
       idr_alloc - allocate new idr entry

SYNOPSIS
       int idr_alloc(struct idr * idr, void * ptr, int start, int end, gfp_t gfp_mask);

ARGUMENTS
       idr
           the (initialized) idr

       ptr
           pointer to be associated with the new id

       start
           the minimum id (inclusive)

       end
           the maximum id (exclusive, <= 0 for max)

       gfp_mask
           memory allocation flags

DESCRIPTION
       Allocate an id in [start, end) and associate it with ptr. If no ID is available in the
       specified range, returns -ENOSPC. On memory allocation failure, returns -ENOMEM.

       Note that end is treated as max when <= 0. This is to always allow using start + N as end
       as long as N is inside integer range.

       The user is responsible for exclusively synchronizing all operations which may modify idr.
       However, read-only accesses such as idr_find or iteration can be performed under RCU read
       lock provided the user destroys ptr in RCU-safe way after removal from idr.

COPYRIGHT
Kernel Hackers Manual 4.8.                 January 2017                              IDR_ALLOC(9)