tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * videobuf2-vmalloc.c - vmalloc memory allocator for videobuf2
3 *
4 * Copyright (C) 2010 Samsung Electronics
5 *
6 * Author: Pawel Osciak <pawel@osciak.com>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation.
11 */
12
13#include <linux/io.h>
14#include <linux/module.h>
15#include <linux/mm.h>
16#include <linux/sched.h>
17#include <linux/slab.h>
18#include <linux/vmalloc.h>
19
20#include <media/videobuf2-core.h>
21#include <media/videobuf2-memops.h>
22
23struct vb2_vmalloc_buf {
24 void *vaddr;
25 struct page **pages;
26 struct vm_area_struct *vma;
27 int write;
28 unsigned long size;
29 unsigned int n_pages;
30 atomic_t refcount;
31 struct vb2_vmarea_handler handler;
32};
33
34static void vb2_vmalloc_put(void *buf_priv);
35
36static void *vb2_vmalloc_alloc(void *alloc_ctx, unsigned long size)
37{
38 struct vb2_vmalloc_buf *buf;
39
40 buf = kzalloc(sizeof(*buf), GFP_KERNEL);
41 if (!buf)
42 return NULL;
43
44 buf->size = size;
45 buf->vaddr = vmalloc_user(buf->size);
46 buf->handler.refcount = &buf->refcount;
47 buf->handler.put = vb2_vmalloc_put;
48 buf->handler.arg = buf;
49
50 if (!buf->vaddr) {
51 pr_debug("vmalloc of size %ld failed\n", buf->size);
52 kfree(buf);
53 return NULL;
54 }
55
56 atomic_inc(&buf->refcount);
57 return buf;
58}
59
60static void vb2_vmalloc_put(void *buf_priv)
61{
62 struct vb2_vmalloc_buf *buf = buf_priv;
63
64 if (atomic_dec_and_test(&buf->refcount)) {
65 vfree(buf->vaddr);
66 kfree(buf);
67 }
68}
69
70static void *vb2_vmalloc_get_userptr(void *alloc_ctx, unsigned long vaddr,
71 unsigned long size, int write)
72{
73 struct vb2_vmalloc_buf *buf;
74 unsigned long first, last;
75 int n_pages, offset;
76 struct vm_area_struct *vma;
77 dma_addr_t physp;
78
79 buf = kzalloc(sizeof(*buf), GFP_KERNEL);
80 if (!buf)
81 return NULL;
82
83 buf->write = write;
84 offset = vaddr & ~PAGE_MASK;
85 buf->size = size;
86
87
88 vma = find_vma(current->mm, vaddr);
89 if (vma && (vma->vm_flags & VM_PFNMAP) && (vma->vm_pgoff)) {
90 if (vb2_get_contig_userptr(vaddr, size, &vma, &physp))
91 goto fail_pages_array_alloc;
92 buf->vma = vma;
93 buf->vaddr = ioremap_nocache(physp, size);
94 if (!buf->vaddr)
95 goto fail_pages_array_alloc;
96 } else {
97 first = vaddr >> PAGE_SHIFT;
98 last = (vaddr + size - 1) >> PAGE_SHIFT;
99 buf->n_pages = last - first + 1;
100 buf->pages = kzalloc(buf->n_pages * sizeof(struct page *),
101 GFP_KERNEL);
102 if (!buf->pages)
103 goto fail_pages_array_alloc;
104
105 /* current->mm->mmap_sem is taken by videobuf2 core */
106 n_pages = get_user_pages(current, current->mm,
107 vaddr & PAGE_MASK, buf->n_pages,
108 write, 1, /* force */
109 buf->pages, NULL);
110 if (n_pages != buf->n_pages)
111 goto fail_get_user_pages;
112
113 buf->vaddr = vm_map_ram(buf->pages, buf->n_pages, -1,
114 PAGE_KERNEL);
115 if (!buf->vaddr)
116 goto fail_get_user_pages;
117 }
118
119 buf->vaddr += offset;
120 return buf;
121
122fail_get_user_pages:
123 pr_debug("get_user_pages requested/got: %d/%d]\n", n_pages,
124 buf->n_pages);
125 while (--n_pages >= 0)
126 put_page(buf->pages[n_pages]);
127 kfree(buf->pages);
128
129fail_pages_array_alloc:
130 kfree(buf);
131
132 return NULL;
133}
134
135static void vb2_vmalloc_put_userptr(void *buf_priv)
136{
137 struct vb2_vmalloc_buf *buf = buf_priv;
138 unsigned long vaddr = (unsigned long)buf->vaddr & PAGE_MASK;
139 unsigned int i;
140
141 if (buf->pages) {
142 if (vaddr)
143 vm_unmap_ram((void *)vaddr, buf->n_pages);
144 for (i = 0; i < buf->n_pages; ++i) {
145 if (buf->write)
146 set_page_dirty_lock(buf->pages[i]);
147 put_page(buf->pages[i]);
148 }
149 kfree(buf->pages);
150 } else {
151 if (buf->vma)
152 vb2_put_vma(buf->vma);
153 iounmap(buf->vaddr);
154 }
155 kfree(buf);
156}
157
158static void *vb2_vmalloc_vaddr(void *buf_priv)
159{
160 struct vb2_vmalloc_buf *buf = buf_priv;
161
162 if (!buf->vaddr) {
163 pr_err("Address of an unallocated plane requested "
164 "or cannot map user pointer\n");
165 return NULL;
166 }
167
168 return buf->vaddr;
169}
170
171static unsigned int vb2_vmalloc_num_users(void *buf_priv)
172{
173 struct vb2_vmalloc_buf *buf = buf_priv;
174 return atomic_read(&buf->refcount);
175}
176
177static int vb2_vmalloc_mmap(void *buf_priv, struct vm_area_struct *vma)
178{
179 struct vb2_vmalloc_buf *buf = buf_priv;
180 int ret;
181
182 if (!buf) {
183 pr_err("No memory to map\n");
184 return -EINVAL;
185 }
186
187 ret = remap_vmalloc_range(vma, buf->vaddr, 0);
188 if (ret) {
189 pr_err("Remapping vmalloc memory, error: %d\n", ret);
190 return ret;
191 }
192
193 /*
194 * Make sure that vm_areas for 2 buffers won't be merged together
195 */
196 vma->vm_flags |= VM_DONTEXPAND;
197
198 /*
199 * Use common vm_area operations to track buffer refcount.
200 */
201 vma->vm_private_data = &buf->handler;
202 vma->vm_ops = &vb2_common_vm_ops;
203
204 vma->vm_ops->open(vma);
205
206 return 0;
207}
208
209const struct vb2_mem_ops vb2_vmalloc_memops = {
210 .alloc = vb2_vmalloc_alloc,
211 .put = vb2_vmalloc_put,
212 .get_userptr = vb2_vmalloc_get_userptr,
213 .put_userptr = vb2_vmalloc_put_userptr,
214 .vaddr = vb2_vmalloc_vaddr,
215 .mmap = vb2_vmalloc_mmap,
216 .num_users = vb2_vmalloc_num_users,
217};
218EXPORT_SYMBOL_GPL(vb2_vmalloc_memops);
219
220MODULE_DESCRIPTION("vmalloc memory handling routines for videobuf2");
221MODULE_AUTHOR("Pawel Osciak <pawel@osciak.com>");
222MODULE_LICENSE("GPL");