dma_pool_create(9) [suse man page]

DMA_POOL_CREATE(9)					    Memory Management in Linux						DMA_POOL_CREATE(9)

NAME

       dma_pool_create - Creates a pool of consistent memory blocks, for dma.

SYNOPSIS

       struct dma_pool * dma_pool_create(const char * name, struct device * dev, size_t size, size_t align, size_t boundary);

ARGUMENTS

       name
	   name of pool, for diagnostics

       dev
	   device that will be doing the DMA

       size
	   size of the blocks in this pool.

       align
	   alignment requirement for blocks; must be a power of two

       boundary
	   returned blocks won't cross this power of two boundary

CONTEXT

       !in_interrupt

DESCRIPTION

       Returns a dma allocation pool with the requested characteristics, or null if one can't be created. Given one of these pools, dma_pool_alloc
       may be used to allocate memory. Such memory will all have "consistent" DMA mappings, accessible by the device and its driver without using
       cache flushing primitives. The actual size of blocks allocated may be larger than requested because of alignment.

       If boundary is nonzero, objects returned from dma_pool_alloc won't cross that size boundary. This is useful for devices which have
       addressing restrictions on individual DMA transfers, such as not crossing boundaries of 4KBytes.

COPYRIGHT

Kernel Hackers Manual 2.6.					     July 2010							DMA_POOL_CREATE(9)

POSIX_MEMALIGN(3)					     Linux Programmer's Manual						 POSIX_MEMALIGN(3)

NAME

       posix_memalign, memalign, valloc - Allocate aligned memory

SYNOPSIS

       #include <stdlib.h>

       int posix_memalign(void **memptr, size_t alignment, size_t size);
       void *memalign(size_t boundary, size_t size);
       void *valloc(size_t size);

DESCRIPTION

       The function posix_memalign() allocates size bytes and places the address of the allocated memory in *memptr.  The address of the allocated
       memory will be a multiple of alignment, which must be a power of two and a multiple of sizeof(void *).

       The obsolete function memalign() allocates size bytes and returns a pointer to the allocated memory.  The memory address will be a multiple
       of boundary, which must be a power of two.

       The  obsolete  function valloc() allocates size bytes and returns a pointer to the allocated memory.  The memory address will be a multiple
       of the page size.  It is equivalent to memalign(sysconf(_SC_PAGESIZE),size).

       For all three routines, the memory is not zeroed.

RETURN VALUE

       memalign() and valloc() return the pointer to the allocated memory, or NULL if the request fails.

       posix_memalign() returns zero on success, or one of the error values listed in the next section on failure. Note that errno is not set.

ERRORS

       EINVAL The alignment parameter was not a power of two, or was not a multiple of sizeof(void *).

       ENOMEM There was insufficient memory to fulfill the allocation request.

NOTES

       posix_memalign() verifies that alignment matches the requirements detailed above.  memalign() may not check that the boundary parameter	is
       correct.

       POSIX  requires	that memory obtained from posix_memalign() can be freed using free().  Some systems provide no way to reclaim memory allo-
       cated with memalign() or valloc() (because one can only pass to free() a pointer gotten from malloc(), while e.g.   memalign()  would  call
       malloc() and then align the obtained value).  GNU libc allows memory obtained from any of these three routines to be reclaimed with free().

       GNU libc malloc() always returns 8-byte aligned memory addresses, so these routines are only needed if you require larger alignment values.

AVAILABILITY

       The  functions  memalign()  and valloc() have been available in all Linux libc libraries.  The function posix_memalign() is available since
       glibc 2.1.91.

CONFORMING TO

       The function valloc() appeared in 3.0 BSD. It is documented as being obsolete in BSD 4.3, and as legacy in SUSv2. It no	longer	occurs	in
       SUSv3.  The function memalign() appears in SunOS 4.1.3 but not in BSD 4.4.  The function posix_memalign() comes from POSIX 1003.1d.

SEE ALSO

       malloc(3), free(3), getpagesize(2), brk(2)

GNU
								    2001-10-11							 POSIX_MEMALIGN(3)