[media] v4l2: vb2-dma-sg: fix memory leak
[linux-2.6.git] / drivers / media / video / videobuf2-dma-sg.c
1 /*
2  * videobuf2-dma-sg.c - dma scatter/gather memory allocator for videobuf2
3  *
4  * Copyright (C) 2010 Samsung Electronics
5  *
6  * Author: Andrzej Pietrasiewicz <andrzej.p@samsung.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/module.h>
14 #include <linux/mm.h>
15 #include <linux/scatterlist.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 #include <media/videobuf2-dma-sg.h>
23
24 struct vb2_dma_sg_buf {
25         void                            *vaddr;
26         struct page                     **pages;
27         int                             write;
28         int                             offset;
29         struct vb2_dma_sg_desc          sg_desc;
30         atomic_t                        refcount;
31         struct vb2_vmarea_handler       handler;
32 };
33
34 static void vb2_dma_sg_put(void *buf_priv);
35
36 static void *vb2_dma_sg_alloc(void *alloc_ctx, unsigned long size)
37 {
38         struct vb2_dma_sg_buf *buf;
39         int i;
40
41         buf = kzalloc(sizeof *buf, GFP_KERNEL);
42         if (!buf)
43                 return NULL;
44
45         buf->vaddr = NULL;
46         buf->write = 0;
47         buf->offset = 0;
48         buf->sg_desc.size = size;
49         buf->sg_desc.num_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
50
51         buf->sg_desc.sglist = vmalloc(buf->sg_desc.num_pages *
52                                       sizeof(*buf->sg_desc.sglist));
53         if (!buf->sg_desc.sglist)
54                 goto fail_sglist_alloc;
55         memset(buf->sg_desc.sglist, 0, buf->sg_desc.num_pages *
56                sizeof(*buf->sg_desc.sglist));
57         sg_init_table(buf->sg_desc.sglist, buf->sg_desc.num_pages);
58
59         buf->pages = kzalloc(buf->sg_desc.num_pages * sizeof(struct page *),
60                              GFP_KERNEL);
61         if (!buf->pages)
62                 goto fail_pages_array_alloc;
63
64         for (i = 0; i < buf->sg_desc.num_pages; ++i) {
65                 buf->pages[i] = alloc_page(GFP_KERNEL);
66                 if (NULL == buf->pages[i])
67                         goto fail_pages_alloc;
68                 sg_set_page(&buf->sg_desc.sglist[i],
69                             buf->pages[i], PAGE_SIZE, 0);
70         }
71
72         buf->handler.refcount = &buf->refcount;
73         buf->handler.put = vb2_dma_sg_put;
74         buf->handler.arg = buf;
75
76         atomic_inc(&buf->refcount);
77
78         printk(KERN_DEBUG "%s: Allocated buffer of %d pages\n",
79                 __func__, buf->sg_desc.num_pages);
80
81         if (!buf->vaddr)
82                 buf->vaddr = vm_map_ram(buf->pages,
83                                         buf->sg_desc.num_pages,
84                                         -1,
85                                         PAGE_KERNEL);
86         return buf;
87
88 fail_pages_alloc:
89         while (--i >= 0)
90                 __free_page(buf->pages[i]);
91         kfree(buf->pages);
92
93 fail_pages_array_alloc:
94         vfree(buf->sg_desc.sglist);
95
96 fail_sglist_alloc:
97         kfree(buf);
98         return NULL;
99 }
100
101 static void vb2_dma_sg_put(void *buf_priv)
102 {
103         struct vb2_dma_sg_buf *buf = buf_priv;
104         int i = buf->sg_desc.num_pages;
105
106         if (atomic_dec_and_test(&buf->refcount)) {
107                 printk(KERN_DEBUG "%s: Freeing buffer of %d pages\n", __func__,
108                         buf->sg_desc.num_pages);
109                 if (buf->vaddr)
110                         vm_unmap_ram(buf->vaddr, buf->sg_desc.num_pages);
111                 vfree(buf->sg_desc.sglist);
112                 while (--i >= 0)
113                         __free_page(buf->pages[i]);
114                 kfree(buf->pages);
115                 kfree(buf);
116         }
117 }
118
119 static void *vb2_dma_sg_get_userptr(void *alloc_ctx, unsigned long vaddr,
120                                     unsigned long size, int write)
121 {
122         struct vb2_dma_sg_buf *buf;
123         unsigned long first, last;
124         int num_pages_from_user, i;
125
126         buf = kzalloc(sizeof *buf, GFP_KERNEL);
127         if (!buf)
128                 return NULL;
129
130         buf->vaddr = NULL;
131         buf->write = write;
132         buf->offset = vaddr & ~PAGE_MASK;
133         buf->sg_desc.size = size;
134
135         first = (vaddr           & PAGE_MASK) >> PAGE_SHIFT;
136         last  = ((vaddr + size - 1) & PAGE_MASK) >> PAGE_SHIFT;
137         buf->sg_desc.num_pages = last - first + 1;
138
139         buf->sg_desc.sglist = vmalloc(
140                 buf->sg_desc.num_pages * sizeof(*buf->sg_desc.sglist));
141         if (!buf->sg_desc.sglist)
142                 goto userptr_fail_sglist_alloc;
143
144         memset(buf->sg_desc.sglist, 0,
145                 buf->sg_desc.num_pages * sizeof(*buf->sg_desc.sglist));
146         sg_init_table(buf->sg_desc.sglist, buf->sg_desc.num_pages);
147
148         buf->pages = kzalloc(buf->sg_desc.num_pages * sizeof(struct page *),
149                              GFP_KERNEL);
150         if (!buf->pages)
151                 goto userptr_fail_pages_array_alloc;
152
153         down_read(&current->mm->mmap_sem);
154         num_pages_from_user = get_user_pages(current, current->mm,
155                                              vaddr & PAGE_MASK,
156                                              buf->sg_desc.num_pages,
157                                              write,
158                                              1, /* force */
159                                              buf->pages,
160                                              NULL);
161         up_read(&current->mm->mmap_sem);
162         if (num_pages_from_user != buf->sg_desc.num_pages)
163                 goto userptr_fail_get_user_pages;
164
165         sg_set_page(&buf->sg_desc.sglist[0], buf->pages[0],
166                     PAGE_SIZE - buf->offset, buf->offset);
167         size -= PAGE_SIZE - buf->offset;
168         for (i = 1; i < buf->sg_desc.num_pages; ++i) {
169                 sg_set_page(&buf->sg_desc.sglist[i], buf->pages[i],
170                             min_t(size_t, PAGE_SIZE, size), 0);
171                 size -= min_t(size_t, PAGE_SIZE, size);
172         }
173         return buf;
174
175 userptr_fail_get_user_pages:
176         printk(KERN_DEBUG "get_user_pages requested/got: %d/%d]\n",
177                num_pages_from_user, buf->sg_desc.num_pages);
178         while (--num_pages_from_user >= 0)
179                 put_page(buf->pages[num_pages_from_user]);
180         kfree(buf->pages);
181
182 userptr_fail_pages_array_alloc:
183         vfree(buf->sg_desc.sglist);
184
185 userptr_fail_sglist_alloc:
186         kfree(buf);
187         return NULL;
188 }
189
190 /*
191  * @put_userptr: inform the allocator that a USERPTR buffer will no longer
192  *               be used
193  */
194 static void vb2_dma_sg_put_userptr(void *buf_priv)
195 {
196         struct vb2_dma_sg_buf *buf = buf_priv;
197         int i = buf->sg_desc.num_pages;
198
199         printk(KERN_DEBUG "%s: Releasing userspace buffer of %d pages\n",
200                __func__, buf->sg_desc.num_pages);
201         if (buf->vaddr)
202                 vm_unmap_ram(buf->vaddr, buf->sg_desc.num_pages);
203         while (--i >= 0) {
204                 if (buf->write)
205                         set_page_dirty_lock(buf->pages[i]);
206                 put_page(buf->pages[i]);
207         }
208         vfree(buf->sg_desc.sglist);
209         kfree(buf->pages);
210         kfree(buf);
211 }
212
213 static void *vb2_dma_sg_vaddr(void *buf_priv)
214 {
215         struct vb2_dma_sg_buf *buf = buf_priv;
216
217         BUG_ON(!buf);
218
219         if (!buf->vaddr)
220                 buf->vaddr = vm_map_ram(buf->pages,
221                                         buf->sg_desc.num_pages,
222                                         -1,
223                                         PAGE_KERNEL);
224
225         /* add offset in case userptr is not page-aligned */
226         return buf->vaddr + buf->offset;
227 }
228
229 static unsigned int vb2_dma_sg_num_users(void *buf_priv)
230 {
231         struct vb2_dma_sg_buf *buf = buf_priv;
232
233         return atomic_read(&buf->refcount);
234 }
235
236 static int vb2_dma_sg_mmap(void *buf_priv, struct vm_area_struct *vma)
237 {
238         struct vb2_dma_sg_buf *buf = buf_priv;
239         unsigned long uaddr = vma->vm_start;
240         unsigned long usize = vma->vm_end - vma->vm_start;
241         int i = 0;
242
243         if (!buf) {
244                 printk(KERN_ERR "No memory to map\n");
245                 return -EINVAL;
246         }
247
248         do {
249                 int ret;
250
251                 ret = vm_insert_page(vma, uaddr, buf->pages[i++]);
252                 if (ret) {
253                         printk(KERN_ERR "Remapping memory, error: %d\n", ret);
254                         return ret;
255                 }
256
257                 uaddr += PAGE_SIZE;
258                 usize -= PAGE_SIZE;
259         } while (usize > 0);
260
261
262         /*
263          * Use common vm_area operations to track buffer refcount.
264          */
265         vma->vm_private_data    = &buf->handler;
266         vma->vm_ops             = &vb2_common_vm_ops;
267
268         vma->vm_ops->open(vma);
269
270         return 0;
271 }
272
273 static void *vb2_dma_sg_cookie(void *buf_priv)
274 {
275         struct vb2_dma_sg_buf *buf = buf_priv;
276
277         return &buf->sg_desc;
278 }
279
280 const struct vb2_mem_ops vb2_dma_sg_memops = {
281         .alloc          = vb2_dma_sg_alloc,
282         .put            = vb2_dma_sg_put,
283         .get_userptr    = vb2_dma_sg_get_userptr,
284         .put_userptr    = vb2_dma_sg_put_userptr,
285         .vaddr          = vb2_dma_sg_vaddr,
286         .mmap           = vb2_dma_sg_mmap,
287         .num_users      = vb2_dma_sg_num_users,
288         .cookie         = vb2_dma_sg_cookie,
289 };
290 EXPORT_SYMBOL_GPL(vb2_dma_sg_memops);
291
292 MODULE_DESCRIPTION("dma scatter/gather memory handling routines for videobuf2");
293 MODULE_AUTHOR("Andrzej Pietrasiewicz");
294 MODULE_LICENSE("GPL");