include/linux/memremap.h

1 /* SPDX-License-Identifier: GPL-2.0 */
6 #include <linux/percpu-refcount.h>
12  * struct vmem_altmap - pre-allocated storage for vmemmap_populate
14  * @reserve: pages mapped, but reserved for driver use (relative to @base)
29  * Specialize ZONE_DEVICE memory into multiple types each having differents
33  * Device memory that is not directly addressable by the CPU: CPU can neither
34  * read nor write private memory. In this case, we do still have struct pages
35  * backing the device memory. Doing so simplifies the implementation, but it is
39  * A more complete discussion of unaddressable memory may be found in
43  * Host memory that has similar access semantics as System RAM i.e. DMA
51  * Host memory that has similar access semantics as System RAM i.e. DMA
53  * that expose memory using a character device.
56  * Device memory residing in a PCI BAR intended for use with Peer-to-Peer
71 	 * device driver to implement its own memory management.)
86 	 * Used for private (un-addressable) device memory only.  Must migrate
95  * struct dev_pagemap - metadata for ZONE_DEVICE mappings
96  * @altmap: pre-allocated/reserved memory for vmemmap allocations
100  * @type: memory type: see MEMORY_* in memory_hotplug.h
105  *	foreign ZONE_DEVICE memory is accessed.
106  * @nr_range: number of ranges to be mapped
107  * @range: range to be mapped when nr_range == 1
108  * @ranges: array of ranges to be mapped when nr_range > 1
128 	if (pgmap->flags & PGMAP_ALTMAP_VALID)  in pgmap_altmap()
129 		return &pgmap->altmap;  in pgmap_altmap()
154 	return ERR_PTR(-ENXIO);  in devm_memremap_pages()
188 		percpu_ref_put(pgmap->ref);  in put_dev_pagemap()