mempool_alloc(9) [centos man page]

MEMPOOL_ALLOC(9)					    Memory Management in Linux						  MEMPOOL_ALLOC(9)

NAME

       mempool_alloc - allocate an element from a specific memory pool

SYNOPSIS

       void * mempool_alloc(mempool_t * pool, gfp_t gfp_mask);

ARGUMENTS

       pool
	   pointer to the memory pool which was allocated via mempool_create.

       gfp_mask
	   the usual allocation bitmask.

DESCRIPTION

       this function only sleeps if the alloc_fn function sleeps or returns NULL. Note that due to preallocation, this function *never* fails when
       called from process contexts. (it might fail if called from an IRQ context.)

COPYRIGHT

Kernel Hackers Manual 3.10					     June 2014							  MEMPOOL_ALLOC(9)

CALL_USERMODEHELPER_(9) 					  Module Support					   CALL_USERMODEHELPER_(9)

NAME

       call_usermodehelper_setup - prepare to call a usermode helper

SYNOPSIS

       struct subprocess_info * call_usermodehelper_setup(char * path, char ** argv, char ** envp, gfp_t gfp_mask,
							  int (*init) (struct subprocess_info *info, struct cred *new),
							  void (*cleanup) (struct subprocess_info *info), void * data);

ARGUMENTS

       path
	   path to usermode executable

       argv
	   arg vector for process

       envp
	   environment for process

       gfp_mask
	   gfp mask for memory allocation

       init
	   an init function

       cleanup
	   a cleanup function

       data
	   arbitrary context sensitive data

DESCRIPTION

       Returns either NULL on allocation failure, or a subprocess_info structure. This should be passed to call_usermodehelper_exec to exec the
       process and free the structure.

       The init function is used to customize the helper process prior to exec. A non-zero return code causes the process to error out, exit, and
       return the failure to the calling process

       The cleanup function is just before ethe subprocess_info is about to be freed. This can be used for freeing the argv and envp. The Function
       must be runnable in either a process context or the context in which call_usermodehelper_exec is called.

COPYRIGHT

Kernel Hackers Manual 3.10					     June 2014						   CALL_USERMODEHELPER_(9)