Commit e2b745f4 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'dma-mapping-4.21-1' of git://git.infradead.org/users/hch/dma-mapping

Pull dma-mapping fixes from Christoph Hellwig:
 "Fix various regressions introduced in this cycles:

   - fix dma-debug tracking for the map_page / map_single
     consolidatation

   - properly stub out DMA mapping symbols for !HAS_DMA builds to avoid
     link failures

   - fix AMD Gart direct mappings

   - setup the dma address for no kernel mappings using the remap
     allocator"

* tag 'dma-mapping-4.21-1' of git://git.infradead.org/users/hch/dma-mapping:
  dma-direct: fix DMA_ATTR_NO_KERNEL_MAPPING for remapped allocations
  x86/amd_gart: fix unmapping of non-GART mappings
  dma-mapping: remove a few unused exports
  dma-mapping: properly stub out the DMA API for !CONFIG_HAS_DMA
  dma-mapping: remove dmam_{declare,release}_coherent_memory
  dma-mapping: implement dmam_alloc_coherent using dmam_alloc_attrs
  dma-mapping: implement dma_map_single_attrs using dma_map_page_attrs
parents 12133258 8270f3a1
......@@ -250,7 +250,6 @@ DMA
dmaenginem_async_device_register()
dmam_alloc_coherent()
dmam_alloc_attrs()
dmam_declare_coherent_memory()
dmam_free_coherent()
dmam_pool_create()
dmam_pool_destroy()
......
......@@ -256,7 +256,15 @@ static void gart_unmap_page(struct device *dev, dma_addr_t dma_addr,
int npages;
int i;
if (dma_addr == DMA_MAPPING_ERROR ||
if (WARN_ON_ONCE(dma_addr == DMA_MAPPING_ERROR))
return;
/*
* This driver will not always use a GART mapping, but might have
* created a direct mapping instead. If that is the case there is
* nothing to unmap here.
*/
if (dma_addr < iommu_bus_base ||
dma_addr >= iommu_bus_base + iommu_size)
return;
......
......@@ -35,13 +35,12 @@ extern void debug_dma_map_single(struct device *dev, const void *addr,
extern void debug_dma_map_page(struct device *dev, struct page *page,
size_t offset, size_t size,
int direction, dma_addr_t dma_addr,
bool map_single);
int direction, dma_addr_t dma_addr);
extern void debug_dma_mapping_error(struct device *dev, dma_addr_t dma_addr);
extern void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
size_t size, int direction, bool map_single);
size_t size, int direction);
extern void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
int nents, int mapped_ents, int direction);
......@@ -95,8 +94,7 @@ static inline void debug_dma_map_single(struct device *dev, const void *addr,
static inline void debug_dma_map_page(struct device *dev, struct page *page,
size_t offset, size_t size,
int direction, dma_addr_t dma_addr,
bool map_single)
int direction, dma_addr_t dma_addr)
{
}
......@@ -106,8 +104,7 @@ static inline void debug_dma_mapping_error(struct device *dev,
}
static inline void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
size_t size, int direction,
bool map_single)
size_t size, int direction)
{
}
......
......@@ -194,33 +194,6 @@ static inline int dma_mmap_from_global_coherent(struct vm_area_struct *vma,
}
#endif /* CONFIG_HAVE_GENERIC_DMA_COHERENT */
#ifdef CONFIG_HAS_DMA
#include <asm/dma-mapping.h>
static inline const struct dma_map_ops *get_dma_ops(struct device *dev)
{
if (dev && dev->dma_ops)
return dev->dma_ops;
return get_arch_dma_ops(dev ? dev->bus : NULL);
}
static inline void set_dma_ops(struct device *dev,
const struct dma_map_ops *dma_ops)
{
dev->dma_ops = dma_ops;
}
#else
/*
* Define the dma api to allow compilation of dma dependent code.
* Code that depends on the dma-mapping API needs to set 'depends on HAS_DMA'
* in its Kconfig, unless it already depends on <something> || COMPILE_TEST,
* where <something> guarantuees the availability of the dma-mapping API.
*/
static inline const struct dma_map_ops *get_dma_ops(struct device *dev)
{
return NULL;
}
#endif
static inline bool dma_is_direct(const struct dma_map_ops *ops)
{
return likely(!ops);
......@@ -284,32 +257,41 @@ static inline void dma_direct_sync_sg_for_cpu(struct device *dev,
}
#endif
static inline dma_addr_t dma_map_single_attrs(struct device *dev, void *ptr,
size_t size,
enum dma_data_direction dir,
unsigned long attrs)
#ifdef CONFIG_HAS_DMA
#include <asm/dma-mapping.h>
static inline const struct dma_map_ops *get_dma_ops(struct device *dev)
{
if (dev && dev->dma_ops)
return dev->dma_ops;
return get_arch_dma_ops(dev ? dev->bus : NULL);
}
static inline void set_dma_ops(struct device *dev,
const struct dma_map_ops *dma_ops)
{
dev->dma_ops = dma_ops;
}
static inline dma_addr_t dma_map_page_attrs(struct device *dev,
struct page *page, size_t offset, size_t size,
enum dma_data_direction dir, unsigned long attrs)
{
const struct dma_map_ops *ops = get_dma_ops(dev);
dma_addr_t addr;
BUG_ON(!valid_dma_direction(dir));
debug_dma_map_single(dev, ptr, size);
if (dma_is_direct(ops))
addr = dma_direct_map_page(dev, virt_to_page(ptr),
offset_in_page(ptr), size, dir, attrs);
addr = dma_direct_map_page(dev, page, offset, size, dir, attrs);
else
addr = ops->map_page(dev, virt_to_page(ptr),
offset_in_page(ptr), size, dir, attrs);
debug_dma_map_page(dev, virt_to_page(ptr),
offset_in_page(ptr), size,
dir, addr, true);
addr = ops->map_page(dev, page, offset, size, dir, attrs);
debug_dma_map_page(dev, page, offset, size, dir, addr);
return addr;
}
static inline void dma_unmap_single_attrs(struct device *dev, dma_addr_t addr,
size_t size,
enum dma_data_direction dir,
unsigned long attrs)
static inline void dma_unmap_page_attrs(struct device *dev, dma_addr_t addr,
size_t size, enum dma_data_direction dir, unsigned long attrs)
{
const struct dma_map_ops *ops = get_dma_ops(dev);
......@@ -318,13 +300,7 @@ static inline void dma_unmap_single_attrs(struct device *dev, dma_addr_t addr,
dma_direct_unmap_page(dev, addr, size, dir, attrs);
else if (ops->unmap_page)
ops->unmap_page(dev, addr, size, dir, attrs);
debug_dma_unmap_page(dev, addr, size, dir, true);
}
static inline void dma_unmap_page_attrs(struct device *dev, dma_addr_t addr,
size_t size, enum dma_data_direction dir, unsigned long attrs)
{
return dma_unmap_single_attrs(dev, addr, size, dir, attrs);
debug_dma_unmap_page(dev, addr, size, dir);
}
/*
......@@ -363,25 +339,6 @@ static inline void dma_unmap_sg_attrs(struct device *dev, struct scatterlist *sg
ops->unmap_sg(dev, sg, nents, dir, attrs);
}
static inline dma_addr_t dma_map_page_attrs(struct device *dev,
struct page *page,
size_t offset, size_t size,
enum dma_data_direction dir,
unsigned long attrs)
{
const struct dma_map_ops *ops = get_dma_ops(dev);
dma_addr_t addr;
BUG_ON(!valid_dma_direction(dir));
if (dma_is_direct(ops))
addr = dma_direct_map_page(dev, page, offset, size, dir, attrs);
else
addr = ops->map_page(dev, page, offset, size, dir, attrs);
debug_dma_map_page(dev, page, offset, size, dir, addr, false);
return addr;
}
static inline dma_addr_t dma_map_resource(struct device *dev,
phys_addr_t phys_addr,
size_t size,
......@@ -431,13 +388,6 @@ static inline void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr,
debug_dma_sync_single_for_cpu(dev, addr, size, dir);
}
static inline void dma_sync_single_range_for_cpu(struct device *dev,
dma_addr_t addr, unsigned long offset, size_t size,
enum dma_data_direction dir)
{
return dma_sync_single_for_cpu(dev, addr + offset, size, dir);
}
static inline void dma_sync_single_for_device(struct device *dev,
dma_addr_t addr, size_t size,
enum dma_data_direction dir)
......@@ -452,13 +402,6 @@ static inline void dma_sync_single_for_device(struct device *dev,
debug_dma_sync_single_for_device(dev, addr, size, dir);
}
static inline void dma_sync_single_range_for_device(struct device *dev,
dma_addr_t addr, unsigned long offset, size_t size,
enum dma_data_direction dir)
{
return dma_sync_single_for_device(dev, addr + offset, size, dir);
}
static inline void
dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
int nelems, enum dma_data_direction dir)
......@@ -488,15 +431,174 @@ dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
}
static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
{
debug_dma_mapping_error(dev, dma_addr);
if (dma_addr == DMA_MAPPING_ERROR)
return -ENOMEM;
return 0;
}
void *dma_alloc_attrs(struct device *dev, size_t size, dma_addr_t *dma_handle,
gfp_t flag, unsigned long attrs);
void dma_free_attrs(struct device *dev, size_t size, void *cpu_addr,
dma_addr_t dma_handle, unsigned long attrs);
void *dmam_alloc_attrs(struct device *dev, size_t size, dma_addr_t *dma_handle,
gfp_t gfp, unsigned long attrs);
void dmam_free_coherent(struct device *dev, size_t size, void *vaddr,
dma_addr_t dma_handle);
void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
enum dma_data_direction dir);
int dma_get_sgtable_attrs(struct device *dev, struct sg_table *sgt,
void *cpu_addr, dma_addr_t dma_addr, size_t size,
unsigned long attrs);
int dma_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
void *cpu_addr, dma_addr_t dma_addr, size_t size,
unsigned long attrs);
int dma_supported(struct device *dev, u64 mask);
int dma_set_mask(struct device *dev, u64 mask);
int dma_set_coherent_mask(struct device *dev, u64 mask);
u64 dma_get_required_mask(struct device *dev);
#else /* CONFIG_HAS_DMA */
static inline dma_addr_t dma_map_page_attrs(struct device *dev,
struct page *page, size_t offset, size_t size,
enum dma_data_direction dir, unsigned long attrs)
{
return DMA_MAPPING_ERROR;
}
static inline void dma_unmap_page_attrs(struct device *dev, dma_addr_t addr,
size_t size, enum dma_data_direction dir, unsigned long attrs)
{
}
static inline int dma_map_sg_attrs(struct device *dev, struct scatterlist *sg,
int nents, enum dma_data_direction dir, unsigned long attrs)
{
return 0;
}
static inline void dma_unmap_sg_attrs(struct device *dev,
struct scatterlist *sg, int nents, enum dma_data_direction dir,
unsigned long attrs)
{
}
static inline dma_addr_t dma_map_resource(struct device *dev,
phys_addr_t phys_addr, size_t size, enum dma_data_direction dir,
unsigned long attrs)
{
return DMA_MAPPING_ERROR;
}
static inline void dma_unmap_resource(struct device *dev, dma_addr_t addr,
size_t size, enum dma_data_direction dir, unsigned long attrs)
{
}
static inline void dma_sync_single_for_cpu(struct device *dev, dma_addr_t addr,
size_t size, enum dma_data_direction dir)
{
}
static inline void dma_sync_single_for_device(struct device *dev,
dma_addr_t addr, size_t size, enum dma_data_direction dir)
{
}
static inline void dma_sync_sg_for_cpu(struct device *dev,
struct scatterlist *sg, int nelems, enum dma_data_direction dir)
{
}
static inline void dma_sync_sg_for_device(struct device *dev,
struct scatterlist *sg, int nelems, enum dma_data_direction dir)
{
}
static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
{
return -ENOMEM;
}
static inline void *dma_alloc_attrs(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t flag, unsigned long attrs)
{
return NULL;
}
static void dma_free_attrs(struct device *dev, size_t size, void *cpu_addr,
dma_addr_t dma_handle, unsigned long attrs)
{
}
static inline void *dmam_alloc_attrs(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
{
return NULL;
}
static inline void dmam_free_coherent(struct device *dev, size_t size,
void *vaddr, dma_addr_t dma_handle)
{
}
static inline void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
enum dma_data_direction dir)
{
}
static inline int dma_get_sgtable_attrs(struct device *dev,
struct sg_table *sgt, void *cpu_addr, dma_addr_t dma_addr,
size_t size, unsigned long attrs)
{
return -ENXIO;
}
static inline int dma_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
void *cpu_addr, dma_addr_t dma_addr, size_t size,
unsigned long attrs)
{
return -ENXIO;
}
static inline int dma_supported(struct device *dev, u64 mask)
{
return 0;
}
static inline int dma_set_mask(struct device *dev, u64 mask)
{
return -EIO;
}
static inline int dma_set_coherent_mask(struct device *dev, u64 mask)
{
return -EIO;
}
static inline u64 dma_get_required_mask(struct device *dev)
{
return 0;
}
#endif /* CONFIG_HAS_DMA */
static inline dma_addr_t dma_map_single_attrs(struct device *dev, void *ptr,
size_t size, enum dma_data_direction dir, unsigned long attrs)
{
debug_dma_map_single(dev, ptr, size);
return dma_map_page_attrs(dev, virt_to_page(ptr), offset_in_page(ptr),
size, dir, attrs);
}
static inline void dma_unmap_single_attrs(struct device *dev, dma_addr_t addr,
size_t size, enum dma_data_direction dir, unsigned long attrs)
{
return dma_unmap_page_attrs(dev, addr, size, dir, attrs);
}
static inline void dma_sync_single_range_for_cpu(struct device *dev,
dma_addr_t addr, unsigned long offset, size_t size,
enum dma_data_direction dir)
{
return dma_sync_single_for_cpu(dev, addr + offset, size, dir);
}
static inline void dma_sync_single_range_for_device(struct device *dev,
dma_addr_t addr, unsigned long offset, size_t size,
enum dma_data_direction dir)
{
return dma_sync_single_for_device(dev, addr + offset, size, dir);
}
#define dma_map_single(d, a, s, r) dma_map_single_attrs(d, a, s, r, 0)
#define dma_unmap_single(d, a, s, r) dma_unmap_single_attrs(d, a, s, r, 0)
#define dma_map_sg(d, s, n, r) dma_map_sg_attrs(d, s, n, r, 0)
#define dma_unmap_sg(d, s, n, r) dma_unmap_sg_attrs(d, s, n, r, 0)
#define dma_map_page(d, p, o, s, r) dma_map_page_attrs(d, p, o, s, r, 0)
#define dma_unmap_page(d, a, s, r) dma_unmap_page_attrs(d, a, s, r, 0)
void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
enum dma_data_direction dir);
#define dma_get_sgtable(d, t, v, h, s) dma_get_sgtable_attrs(d, t, v, h, s, 0)
#define dma_mmap_coherent(d, v, c, h, s) dma_mmap_attrs(d, v, c, h, s, 0)
extern int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
void *cpu_addr, dma_addr_t dma_addr, size_t size,
......@@ -516,25 +618,10 @@ bool dma_in_atomic_pool(void *start, size_t size);
void *dma_alloc_from_pool(size_t size, struct page **ret_page, gfp_t flags);
bool dma_free_from_pool(void *start, size_t size);
int dma_mmap_attrs(struct device *dev, struct vm_area_struct *vma,
void *cpu_addr, dma_addr_t dma_addr, size_t size,
unsigned long attrs);
#define dma_mmap_coherent(d, v, c, h, s) dma_mmap_attrs(d, v, c, h, s, 0)
int
dma_common_get_sgtable(struct device *dev, struct sg_table *sgt, void *cpu_addr,
dma_addr_t dma_addr, size_t size, unsigned long attrs);
int dma_get_sgtable_attrs(struct device *dev, struct sg_table *sgt,
void *cpu_addr, dma_addr_t dma_addr, size_t size,
unsigned long attrs);
#define dma_get_sgtable(d, t, v, h, s) dma_get_sgtable_attrs(d, t, v, h, s, 0)
void *dma_alloc_attrs(struct device *dev, size_t size, dma_addr_t *dma_handle,
gfp_t flag, unsigned long attrs);
void dma_free_attrs(struct device *dev, size_t size, void *cpu_addr,
dma_addr_t dma_handle, unsigned long attrs);
static inline void *dma_alloc_coherent(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp)
{
......@@ -549,18 +636,6 @@ static inline void dma_free_coherent(struct device *dev, size_t size,
return dma_free_attrs(dev, size, cpu_addr, dma_handle, 0);
}
static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
{
debug_dma_mapping_error(dev, dma_addr);
if (dma_addr == DMA_MAPPING_ERROR)
return -ENOMEM;
return 0;
}
int dma_supported(struct device *dev, u64 mask);
int dma_set_mask(struct device *dev, u64 mask);
int dma_set_coherent_mask(struct device *dev, u64 mask);
static inline u64 dma_get_mask(struct device *dev)
{
......@@ -593,8 +668,6 @@ static inline int dma_coerce_mask_and_coherent(struct device *dev, u64 mask)
return dma_set_mask_and_coherent(dev, mask);
}
extern u64 dma_get_required_mask(struct device *dev);
#ifndef arch_setup_dma_ops
static inline void arch_setup_dma_ops(struct device *dev, u64 dma_base,
u64 size, const struct iommu_ops *iommu,
......@@ -691,43 +764,12 @@ dma_mark_declared_memory_occupied(struct device *dev,
}
#endif /* CONFIG_HAVE_GENERIC_DMA_COHERENT */
/*
* Managed DMA API
*/
#ifdef CONFIG_HAS_DMA
extern void *dmam_alloc_coherent(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp);
extern void dmam_free_coherent(struct device *dev, size_t size, void *vaddr,
dma_addr_t dma_handle);
#else /* !CONFIG_HAS_DMA */
static inline void *dmam_alloc_coherent(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp)
{ return NULL; }
static inline void dmam_free_coherent(struct device *dev, size_t size,
void *vaddr, dma_addr_t dma_handle) { }
#endif /* !CONFIG_HAS_DMA */
extern void *dmam_alloc_attrs(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp,
unsigned long attrs);
#ifdef CONFIG_HAVE_GENERIC_DMA_COHERENT
extern int dmam_declare_coherent_memory(struct device *dev,
phys_addr_t phys_addr,
dma_addr_t device_addr, size_t size,
int flags);
extern void dmam_release_declared_memory(struct device *dev);
#else /* CONFIG_HAVE_GENERIC_DMA_COHERENT */
static inline int dmam_declare_coherent_memory(struct device *dev,
phys_addr_t phys_addr, dma_addr_t device_addr,
size_t size, gfp_t gfp)
{
return 0;
}
static inline void dmam_release_declared_memory(struct device *dev)
{
return dmam_alloc_attrs(dev, size, dma_handle, gfp,
(gfp & __GFP_NOWARN) ? DMA_ATTR_NO_WARN : 0);
}
#endif /* CONFIG_HAVE_GENERIC_DMA_COHERENT */
static inline void *dma_alloc_wc(struct device *dev, size_t size,
dma_addr_t *dma_addr, gfp_t gfp)
......
......@@ -223,7 +223,6 @@ int dma_alloc_from_dev_coherent(struct device *dev, ssize_t size,
*/
return mem->flags & DMA_MEMORY_EXCLUSIVE;
}
EXPORT_SYMBOL(dma_alloc_from_dev_coherent);
void *dma_alloc_from_global_coherent(ssize_t size, dma_addr_t *dma_handle)
{
......@@ -268,7 +267,6 @@ int dma_release_from_dev_coherent(struct device *dev, int order, void *vaddr)
return __dma_release_from_coherent(mem, order, vaddr);
}
EXPORT_SYMBOL(dma_release_from_dev_coherent);
int dma_release_from_global_coherent(int order, void *vaddr)
{
......
......@@ -49,7 +49,6 @@
enum {
dma_debug_single,
dma_debug_page,
dma_debug_sg,
dma_debug_coherent,
dma_debug_resource,
......@@ -1300,8 +1299,7 @@ void debug_dma_map_single(struct device *dev, const void *addr,
EXPORT_SYMBOL(debug_dma_map_single);
void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
size_t size, int direction, dma_addr_t dma_addr,
bool map_single)
size_t size, int direction, dma_addr_t dma_addr)
{
struct dma_debug_entry *entry;
......@@ -1316,7 +1314,7 @@ void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
return;
entry->dev = dev;
entry->type = dma_debug_page;
entry->type = dma_debug_single;
entry->pfn = page_to_pfn(page);
entry->offset = offset,
entry->dev_addr = dma_addr;
......@@ -1324,9 +1322,6 @@ void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
entry->direction = direction;
entry->map_err_type = MAP_ERR_NOT_CHECKED;
if (map_single)
entry->type = dma_debug_single;
check_for_stack(dev, page, offset);
if (!PageHighMem(page)) {
......@@ -1378,10 +1373,10 @@ void debug_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
EXPORT_SYMBOL(debug_dma_mapping_error);
void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
size_t size, int direction, bool map_single)
size_t size, int direction)
{
struct dma_debug_entry ref = {
.type = dma_debug_page,
.type = dma_debug_single,
.dev = dev,
.dev_addr = addr,
.size = size,
......@@ -1390,10 +1385,6 @@ void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
if (unlikely(dma_debug_disabled()))
return;
if (map_single)
ref.type = dma_debug_single;
check_unmap(&ref);
}
EXPORT_SYMBOL(debug_dma_unmap_page);
......@@ -1521,7 +1512,6 @@ void debug_dma_alloc_coherent(struct device *dev, size_t size,
add_dma_entry(entry);
}
EXPORT_SYMBOL(debug_dma_alloc_coherent);
void debug_dma_free_coherent(struct device *dev, size_t size,
void *virt, dma_addr_t addr)
......@@ -1549,7 +1539,6 @@ void debug_dma_free_coherent(struct device *dev, size_t size,
check_unmap(&ref);
}
EXPORT_SYMBOL(debug_dma_free_coherent);
void debug_dma_map_resource(struct device *dev, phys_addr_t addr, size_t size,
int direction, dma_addr_t dma_addr)
......
......@@ -45,45 +45,6 @@ static int dmam_match(struct device *dev, void *res, void *match_data)
return 0;
}
/**
* dmam_alloc_coherent - Managed dma_alloc_coherent()
* @dev: Device to allocate coherent memory for
* @size: Size of allocation
* @dma_handle: Out argument for allocated DMA handle
* @gfp: Allocation flags
*
* Managed dma_alloc_coherent(). Memory allocated using this function
* will be automatically released on driver detach.
*
* RETURNS:
* Pointer to allocated memory on success, NULL on failure.
*/
void *dmam_alloc_coherent(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp)
{
struct dma_devres *dr;
void *vaddr;
dr = devres_alloc(dmam_release, sizeof