1
2#include <linux/kernel.h>
3#include <linux/errno.h>
4#include <linux/err.h>
5#include <linux/mm.h>
6#include <linux/slab.h>
7#include <linux/vmalloc.h>
8#include <linux/pagemap.h>
9#include <linux/sched.h>
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34int get_vaddr_frames(unsigned long start, unsigned int nr_frames,
35 unsigned int gup_flags, struct frame_vector *vec)
36{
37 struct mm_struct *mm = current->mm;
38 struct vm_area_struct *vma;
39 int ret = 0;
40 int err;
41 int locked;
42
43 if (nr_frames == 0)
44 return 0;
45
46 if (WARN_ON_ONCE(nr_frames > vec->nr_allocated))
47 nr_frames = vec->nr_allocated;
48
49 down_read(&mm->mmap_sem);
50 locked = 1;
51 vma = find_vma_intersection(mm, start, start + 1);
52 if (!vma) {
53 ret = -EFAULT;
54 goto out;
55 }
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63
64
65 if (vma_is_fsdax(vma)) {
66 ret = -EOPNOTSUPP;
67 goto out;
68 }
69
70 if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) {
71 vec->got_ref = true;
72 vec->is_pfns = false;
73 ret = get_user_pages_locked(start, nr_frames,
74 gup_flags, (struct page **)(vec->ptrs), &locked);
75 goto out;
76 }
77
78 vec->got_ref = false;
79 vec->is_pfns = true;
80 do {
81 unsigned long *nums = frame_vector_pfns(vec);
82
83 while (ret < nr_frames && start + PAGE_SIZE <= vma->vm_end) {
84 err = follow_pfn(vma, start, &nums[ret]);
85 if (err) {
86 if (ret == 0)
87 ret = err;
88 goto out;
89 }
90 start += PAGE_SIZE;
91 ret++;
92 }
93
94
95
96
97 if (ret >= nr_frames || start < vma->vm_end)
98 break;
99 vma = find_vma_intersection(mm, start, start + 1);
100 } while (vma && vma->vm_flags & (VM_IO | VM_PFNMAP));
101out:
102 if (locked)
103 up_read(&mm->mmap_sem);
104 if (!ret)
105 ret = -EFAULT;
106 if (ret > 0)
107 vec->nr_frames = ret;
108 return ret;
109}
110EXPORT_SYMBOL(get_vaddr_frames);
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119
120
121void put_vaddr_frames(struct frame_vector *vec)
122{
123 int i;
124 struct page **pages;
125
126 if (!vec->got_ref)
127 goto out;
128 pages = frame_vector_pages(vec);
129
130
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132
133
134 if (WARN_ON(IS_ERR(pages)))
135 goto out;
136 for (i = 0; i < vec->nr_frames; i++)
137 put_page(pages[i]);
138 vec->got_ref = false;
139out:
140 vec->nr_frames = 0;
141}
142EXPORT_SYMBOL(put_vaddr_frames);
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151
152int frame_vector_to_pages(struct frame_vector *vec)
153{
154 int i;
155 unsigned long *nums;
156 struct page **pages;
157
158 if (!vec->is_pfns)
159 return 0;
160 nums = frame_vector_pfns(vec);
161 for (i = 0; i < vec->nr_frames; i++)
162 if (!pfn_valid(nums[i]))
163 return -EINVAL;
164 pages = (struct page **)nums;
165 for (i = 0; i < vec->nr_frames; i++)
166 pages[i] = pfn_to_page(nums[i]);
167 vec->is_pfns = false;
168 return 0;
169}
170EXPORT_SYMBOL(frame_vector_to_pages);
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177
178void frame_vector_to_pfns(struct frame_vector *vec)
179{
180 int i;
181 unsigned long *nums;
182 struct page **pages;
183
184 if (vec->is_pfns)
185 return;
186 pages = (struct page **)(vec->ptrs);
187 nums = (unsigned long *)pages;
188 for (i = 0; i < vec->nr_frames; i++)
189 nums[i] = page_to_pfn(pages[i]);
190 vec->is_pfns = true;
191}
192EXPORT_SYMBOL(frame_vector_to_pfns);
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200
201struct frame_vector *frame_vector_create(unsigned int nr_frames)
202{
203 struct frame_vector *vec;
204 int size = sizeof(struct frame_vector) + sizeof(void *) * nr_frames;
205
206 if (WARN_ON_ONCE(nr_frames == 0))
207 return NULL;
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209
210
211
212 if (WARN_ON_ONCE(nr_frames > INT_MAX / sizeof(void *) / 2))
213 return NULL;
214
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217
218 vec = kvmalloc(size, GFP_KERNEL);
219 if (!vec)
220 return NULL;
221 vec->nr_allocated = nr_frames;
222 vec->nr_frames = 0;
223 return vec;
224}
225EXPORT_SYMBOL(frame_vector_create);
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232
233void frame_vector_destroy(struct frame_vector *vec)
234{
235
236 VM_BUG_ON(vec->nr_frames > 0);
237 kvfree(vec);
238}
239EXPORT_SYMBOL(frame_vector_destroy);
240