1
2#include <linux/mm.h>
3#include <linux/rmap.h>
4#include <linux/hugetlb.h>
5#include <linux/swap.h>
6#include <linux/swapops.h>
7
8#include "internal.h"
9
10static inline bool not_found(struct page_vma_mapped_walk *pvmw)
11{
12 page_vma_mapped_walk_done(pvmw);
13 return false;
14}
15
16static bool map_pte(struct page_vma_mapped_walk *pvmw)
17{
18 pvmw->pte = pte_offset_map(pvmw->pmd, pvmw->address);
19 if (!(pvmw->flags & PVMW_SYNC)) {
20 if (pvmw->flags & PVMW_MIGRATION) {
21 if (!is_swap_pte(*pvmw->pte))
22 return false;
23 } else {
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38
39 if (is_swap_pte(*pvmw->pte)) {
40 swp_entry_t entry;
41
42
43 entry = pte_to_swp_entry(*pvmw->pte);
44 if (!is_device_private_entry(entry) &&
45 !is_device_exclusive_entry(entry))
46 return false;
47 } else if (!pte_present(*pvmw->pte))
48 return false;
49 }
50 }
51 pvmw->ptl = pte_lockptr(pvmw->vma->vm_mm, pvmw->pmd);
52 spin_lock(pvmw->ptl);
53 return true;
54}
55
56static inline bool pfn_is_match(struct page *page, unsigned long pfn)
57{
58 unsigned long page_pfn = page_to_pfn(page);
59
60
61 if (!PageTransCompound(page) || PageHuge(page))
62 return page_pfn == pfn;
63
64
65 return pfn >= page_pfn && pfn - page_pfn < thp_nr_pages(page);
66}
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86
87static bool check_pte(struct page_vma_mapped_walk *pvmw)
88{
89 unsigned long pfn;
90
91 if (pvmw->flags & PVMW_MIGRATION) {
92 swp_entry_t entry;
93 if (!is_swap_pte(*pvmw->pte))
94 return false;
95 entry = pte_to_swp_entry(*pvmw->pte);
96
97 if (!is_migration_entry(entry) &&
98 !is_device_exclusive_entry(entry))
99 return false;
100
101 pfn = swp_offset(entry);
102 } else if (is_swap_pte(*pvmw->pte)) {
103 swp_entry_t entry;
104
105
106 entry = pte_to_swp_entry(*pvmw->pte);
107 if (!is_device_private_entry(entry) &&
108 !is_device_exclusive_entry(entry))
109 return false;
110
111 pfn = swp_offset(entry);
112 } else {
113 if (!pte_present(*pvmw->pte))
114 return false;
115
116 pfn = pte_pfn(*pvmw->pte);
117 }
118
119 return pfn_is_match(pvmw->page, pfn);
120}
121
122static void step_forward(struct page_vma_mapped_walk *pvmw, unsigned long size)
123{
124 pvmw->address = (pvmw->address + size) & ~(size - 1);
125 if (!pvmw->address)
126 pvmw->address = ULONG_MAX;
127}
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153bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
154{
155 struct mm_struct *mm = pvmw->vma->vm_mm;
156 struct page *page = pvmw->page;
157 unsigned long end;
158 pgd_t *pgd;
159 p4d_t *p4d;
160 pud_t *pud;
161 pmd_t pmde;
162
163
164 if (pvmw->pmd && !pvmw->pte)
165 return not_found(pvmw);
166
167 if (unlikely(PageHuge(page))) {
168
169 if (pvmw->pte)
170 return not_found(pvmw);
171
172
173 pvmw->pte = huge_pte_offset(mm, pvmw->address, page_size(page));
174 if (!pvmw->pte)
175 return false;
176
177 pvmw->ptl = huge_pte_lockptr(page_hstate(page), mm, pvmw->pte);
178 spin_lock(pvmw->ptl);
179 if (!check_pte(pvmw))
180 return not_found(pvmw);
181 return true;
182 }
183
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187
188
189
190 end = PageTransCompound(page) ?
191 vma_address_end(page, pvmw->vma) :
192 pvmw->address + PAGE_SIZE;
193 if (pvmw->pte)
194 goto next_pte;
195restart:
196 do {
197 pgd = pgd_offset(mm, pvmw->address);
198 if (!pgd_present(*pgd)) {
199 step_forward(pvmw, PGDIR_SIZE);
200 continue;
201 }
202 p4d = p4d_offset(pgd, pvmw->address);
203 if (!p4d_present(*p4d)) {
204 step_forward(pvmw, P4D_SIZE);
205 continue;
206 }
207 pud = pud_offset(p4d, pvmw->address);
208 if (!pud_present(*pud)) {
209 step_forward(pvmw, PUD_SIZE);
210 continue;
211 }
212
213 pvmw->pmd = pmd_offset(pud, pvmw->address);
214
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218
219 pmde = READ_ONCE(*pvmw->pmd);
220
221 if (pmd_trans_huge(pmde) || is_pmd_migration_entry(pmde)) {
222 pvmw->ptl = pmd_lock(mm, pvmw->pmd);
223 pmde = *pvmw->pmd;
224 if (likely(pmd_trans_huge(pmde))) {
225 if (pvmw->flags & PVMW_MIGRATION)
226 return not_found(pvmw);
227 if (pmd_page(pmde) != page)
228 return not_found(pvmw);
229 return true;
230 }
231 if (!pmd_present(pmde)) {
232 swp_entry_t entry;
233
234 if (!thp_migration_supported() ||
235 !(pvmw->flags & PVMW_MIGRATION))
236 return not_found(pvmw);
237 entry = pmd_to_swp_entry(pmde);
238 if (!is_migration_entry(entry) ||
239 pfn_swap_entry_to_page(entry) != page)
240 return not_found(pvmw);
241 return true;
242 }
243
244 spin_unlock(pvmw->ptl);
245 pvmw->ptl = NULL;
246 } else if (!pmd_present(pmde)) {
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248
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250
251
252 if ((pvmw->flags & PVMW_SYNC) &&
253 PageTransCompound(page)) {
254 spinlock_t *ptl = pmd_lock(mm, pvmw->pmd);
255
256 spin_unlock(ptl);
257 }
258 step_forward(pvmw, PMD_SIZE);
259 continue;
260 }
261 if (!map_pte(pvmw))
262 goto next_pte;
263this_pte:
264 if (check_pte(pvmw))
265 return true;
266next_pte:
267 do {
268 pvmw->address += PAGE_SIZE;
269 if (pvmw->address >= end)
270 return not_found(pvmw);
271
272 if ((pvmw->address & (PMD_SIZE - PAGE_SIZE)) == 0) {
273 if (pvmw->ptl) {
274 spin_unlock(pvmw->ptl);
275 pvmw->ptl = NULL;
276 }
277 pte_unmap(pvmw->pte);
278 pvmw->pte = NULL;
279 goto restart;
280 }
281 pvmw->pte++;
282 if ((pvmw->flags & PVMW_SYNC) && !pvmw->ptl) {
283 pvmw->ptl = pte_lockptr(mm, pvmw->pmd);
284 spin_lock(pvmw->ptl);
285 }
286 } while (pte_none(*pvmw->pte));
287
288 if (!pvmw->ptl) {
289 pvmw->ptl = pte_lockptr(mm, pvmw->pmd);
290 spin_lock(pvmw->ptl);
291 }
292 goto this_pte;
293 } while (pvmw->address < end);
294
295 return false;
296}
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306
307int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma)
308{
309 struct page_vma_mapped_walk pvmw = {
310 .page = page,
311 .vma = vma,
312 .flags = PVMW_SYNC,
313 };
314
315 pvmw.address = vma_address(page, vma);
316 if (pvmw.address == -EFAULT)
317 return 0;
318 if (!page_vma_mapped_walk(&pvmw))
319 return 0;
320 page_vma_mapped_walk_done(&pvmw);
321 return 1;
322}
323