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Diffstat (limited to 'mm')
-rw-r--r--mm/memory.c37
1 files changed, 25 insertions, 12 deletions
diff --git a/mm/memory.c b/mm/memory.c
index ece04963158e..107b619cfb16 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1277,22 +1277,28 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
1277 unsigned long address, pte_t *page_table, pmd_t *pmd, 1277 unsigned long address, pte_t *page_table, pmd_t *pmd,
1278 spinlock_t *ptl, pte_t orig_pte) 1278 spinlock_t *ptl, pte_t orig_pte)
1279{ 1279{
1280 struct page *old_page, *new_page; 1280 struct page *old_page, *src_page, *new_page;
1281 unsigned long pfn = pte_pfn(orig_pte); 1281 unsigned long pfn = pte_pfn(orig_pte);
1282 pte_t entry; 1282 pte_t entry;
1283 int ret = VM_FAULT_MINOR; 1283 int ret = VM_FAULT_MINOR;
1284 1284
1285 BUG_ON(vma->vm_flags & VM_UNPAGED);
1286
1287 if (unlikely(!pfn_valid(pfn))) { 1285 if (unlikely(!pfn_valid(pfn))) {
1288 /* 1286 /*
1289 * Page table corrupted: show pte and kill process. 1287 * Page table corrupted: show pte and kill process.
1288 * Or it's an attempt to COW an out-of-map VM_UNPAGED
1289 * entry, which copy_user_highpage does not support.
1290 */ 1290 */
1291 print_bad_pte(vma, orig_pte, address); 1291 print_bad_pte(vma, orig_pte, address);
1292 ret = VM_FAULT_OOM; 1292 ret = VM_FAULT_OOM;
1293 goto unlock; 1293 goto unlock;
1294 } 1294 }
1295 old_page = pfn_to_page(pfn); 1295 old_page = pfn_to_page(pfn);
1296 src_page = old_page;
1297
1298 if (unlikely(vma->vm_flags & VM_UNPAGED)) {
1299 old_page = NULL;
1300 goto gotten;
1301 }
1296 1302
1297 if (PageAnon(old_page) && !TestSetPageLocked(old_page)) { 1303 if (PageAnon(old_page) && !TestSetPageLocked(old_page)) {
1298 int reuse = can_share_swap_page(old_page); 1304 int reuse = can_share_swap_page(old_page);
@@ -1313,11 +1319,12 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
1313 * Ok, we need to copy. Oh, well.. 1319 * Ok, we need to copy. Oh, well..
1314 */ 1320 */
1315 page_cache_get(old_page); 1321 page_cache_get(old_page);
1322gotten:
1316 pte_unmap_unlock(page_table, ptl); 1323 pte_unmap_unlock(page_table, ptl);
1317 1324
1318 if (unlikely(anon_vma_prepare(vma))) 1325 if (unlikely(anon_vma_prepare(vma)))
1319 goto oom; 1326 goto oom;
1320 if (old_page == ZERO_PAGE(address)) { 1327 if (src_page == ZERO_PAGE(address)) {
1321 new_page = alloc_zeroed_user_highpage(vma, address); 1328 new_page = alloc_zeroed_user_highpage(vma, address);
1322 if (!new_page) 1329 if (!new_page)
1323 goto oom; 1330 goto oom;
@@ -1325,7 +1332,7 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
1325 new_page = alloc_page_vma(GFP_HIGHUSER, vma, address); 1332 new_page = alloc_page_vma(GFP_HIGHUSER, vma, address);
1326 if (!new_page) 1333 if (!new_page)
1327 goto oom; 1334 goto oom;
1328 copy_user_highpage(new_page, old_page, address); 1335 copy_user_highpage(new_page, src_page, address);
1329 } 1336 }
1330 1337
1331 /* 1338 /*
@@ -1333,11 +1340,14 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
1333 */ 1340 */
1334 page_table = pte_offset_map_lock(mm, pmd, address, &ptl); 1341 page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
1335 if (likely(pte_same(*page_table, orig_pte))) { 1342 if (likely(pte_same(*page_table, orig_pte))) {
1336 page_remove_rmap(old_page); 1343 if (old_page) {
1337 if (!PageAnon(old_page)) { 1344 page_remove_rmap(old_page);
1345 if (!PageAnon(old_page)) {
1346 dec_mm_counter(mm, file_rss);
1347 inc_mm_counter(mm, anon_rss);
1348 }
1349 } else
1338 inc_mm_counter(mm, anon_rss); 1350 inc_mm_counter(mm, anon_rss);
1339 dec_mm_counter(mm, file_rss);
1340 }
1341 flush_cache_page(vma, address, pfn); 1351 flush_cache_page(vma, address, pfn);
1342 entry = mk_pte(new_page, vma->vm_page_prot); 1352 entry = mk_pte(new_page, vma->vm_page_prot);
1343 entry = maybe_mkwrite(pte_mkdirty(entry), vma); 1353 entry = maybe_mkwrite(pte_mkdirty(entry), vma);
@@ -1351,13 +1361,16 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
1351 new_page = old_page; 1361 new_page = old_page;
1352 ret |= VM_FAULT_WRITE; 1362 ret |= VM_FAULT_WRITE;
1353 } 1363 }
1354 page_cache_release(new_page); 1364 if (new_page)
1355 page_cache_release(old_page); 1365 page_cache_release(new_page);
1366 if (old_page)
1367 page_cache_release(old_page);
1356unlock: 1368unlock:
1357 pte_unmap_unlock(page_table, ptl); 1369 pte_unmap_unlock(page_table, ptl);
1358 return ret; 1370 return ret;
1359oom: 1371oom:
1360 page_cache_release(old_page); 1372 if (old_page)
1373 page_cache_release(old_page);
1361 return VM_FAULT_OOM; 1374 return VM_FAULT_OOM;
1362} 1375}
1363 1376