Eric Lee / linux-smarc-t335x-v3.2

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Commit 58fa879e1e640a1856f736b418984ebeccee1c95

Authored by Hugh Dickins
Committed by Linus Torvalds
1 parent a13ea5b759
Exists in master and in 4 other branches v3.2_AM335xPSP_04.06.00.11, v3.2_NEWT335xPSP_04.06.00.11, v3.2_SBC_SMARTMEN, v3.2_SMARCT335xPSP_04.06.00.11

mm: FOLL flags for GUP flags 

__get_user_pages() has been taking its own GUP flags, then processing
them into FOLL flags for follow_page().  Though oddly named, the FOLL
flags are more widely used, so pass them to __get_user_pages() now.
Sorry, VM flags, VM_FAULT flags and FAULT_FLAGs are still distinct.

(The patch to __get_user_pages() looks peculiar, with both gup_flags
and foll_flags: the gup_flags remain constant; but as before there's
an exceptional case, out of scope of the patch, in which foll_flags
per page have FOLL_WRITE masked off.)

Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Rik van Riel <riel@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Showing 5 changed files with 31 additions and 40 deletions Side-by-side Diff

... ... @@ -1232,6 +1232,7 @@
1232 1232 #define FOLL_TOUCH 0x02 /* mark page accessed */
1233 1233 #define FOLL_GET 0x04 /* do get_page on page */
1234 1234 #define FOLL_DUMP 0x08 /* give error on hole if it would be zero */
  1235 +#define FOLL_FORCE 0x10 /* get_user_pages read/write w/o permission */
1235 1236  
1236 1237 typedef int (*pte_fn_t)(pte_t *pte, pgtable_t token, unsigned long addr,
1237 1238 void *data);
... ... @@ -250,12 +250,8 @@
250 250 }
251 251 #endif /* CONFIG_SPARSEMEM */
252 252  
253   -#define GUP_FLAGS_WRITE 0x01
254   -#define GUP_FLAGS_FORCE 0x02
255   -#define GUP_FLAGS_DUMP 0x04
256   -
257 253 int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
258   - unsigned long start, int len, int flags,
  254 + unsigned long start, int len, unsigned int foll_flags,
259 255 struct page **pages, struct vm_area_struct **vmas);
260 256  
261 257 #define ZONE_RECLAIM_NOSCAN -2
... ... @@ -1209,27 +1209,29 @@
1209 1209 }
1210 1210  
1211 1211 int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
1212   - unsigned long start, int nr_pages, int flags,
  1212 + unsigned long start, int nr_pages, unsigned int gup_flags,
1213 1213 struct page **pages, struct vm_area_struct **vmas)
1214 1214 {
1215 1215 int i;
1216   - unsigned int vm_flags = 0;
1217   - int write = !!(flags & GUP_FLAGS_WRITE);
1218   - int force = !!(flags & GUP_FLAGS_FORCE);
  1216 + unsigned long vm_flags;
1219 1217  
1220 1218 if (nr_pages <= 0)
1221 1219 return 0;
  1220 +
  1221 + VM_BUG_ON(!!pages != !!(gup_flags & FOLL_GET));
  1222 +
1222 1223 /*
1223 1224 * Require read or write permissions.
1224   - * If 'force' is set, we only require the "MAY" flags.
  1225 + * If FOLL_FORCE is set, we only require the "MAY" flags.
1225 1226 */
1226   - vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
1227   - vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
  1227 + vm_flags = (gup_flags & FOLL_WRITE) ?
  1228 + (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
  1229 + vm_flags &= (gup_flags & FOLL_FORCE) ?
  1230 + (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
1228 1231 i = 0;
1229 1232  
1230 1233 do {
1231 1234 struct vm_area_struct *vma;
1232   - unsigned int foll_flags;
1233 1235  
1234 1236 vma = find_extend_vma(mm, start);
1235 1237 if (!vma && in_gate_area(tsk, start)) {
... ... @@ -1241,7 +1243,7 @@
1241 1243 pte_t *pte;
1242 1244  
1243 1245 /* user gate pages are read-only */
1244   - if (write)
  1246 + if (gup_flags & FOLL_WRITE)
1245 1247 return i ? : -EFAULT;
1246 1248 if (pg > TASK_SIZE)
1247 1249 pgd = pgd_offset_k(pg);
1248 1250  
1249 1251  
... ... @@ -1278,22 +1280,15 @@
1278 1280 !(vm_flags & vma->vm_flags))
1279 1281 return i ? : -EFAULT;
1280 1282  
1281   - foll_flags = FOLL_TOUCH;
1282   - if (pages)
1283   - foll_flags |= FOLL_GET;
1284   - if (flags & GUP_FLAGS_DUMP)
1285   - foll_flags |= FOLL_DUMP;
1286   - if (write)
1287   - foll_flags |= FOLL_WRITE;
1288   -
1289 1283 if (is_vm_hugetlb_page(vma)) {
1290 1284 i = follow_hugetlb_page(mm, vma, pages, vmas,
1291   - &start, &nr_pages, i, foll_flags);
  1285 + &start, &nr_pages, i, gup_flags);
1292 1286 continue;
1293 1287 }
1294 1288  
1295 1289 do {
1296 1290 struct page *page;
  1291 + unsigned int foll_flags = gup_flags;
1297 1292  
1298 1293 /*
1299 1294 * If we have a pending SIGKILL, don't keep faulting
... ... @@ -1302,9 +1297,6 @@
1302 1297 if (unlikely(fatal_signal_pending(current)))
1303 1298 return i ? i : -ERESTARTSYS;
1304 1299  
1305   - if (write)
1306   - foll_flags |= FOLL_WRITE;
1307   -
1308 1300 cond_resched();
1309 1301 while (!(page = follow_page(vma, start, foll_flags))) {
1310 1302 int ret;
1311 1303  
1312 1304  
1313 1305  
... ... @@ -1415,12 +1407,14 @@
1415 1407 unsigned long start, int nr_pages, int write, int force,
1416 1408 struct page **pages, struct vm_area_struct **vmas)
1417 1409 {
1418   - int flags = 0;
  1410 + int flags = FOLL_TOUCH;
1419 1411  
  1412 + if (pages)
  1413 + flags |= FOLL_GET;
1420 1414 if (write)
1421   - flags |= GUP_FLAGS_WRITE;
  1415 + flags |= FOLL_WRITE;
1422 1416 if (force)
1423   - flags |= GUP_FLAGS_FORCE;
  1417 + flags |= FOLL_FORCE;
1424 1418  
1425 1419 return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas);
1426 1420 }
... ... @@ -1447,7 +1441,7 @@
1447 1441 struct page *page;
1448 1442  
1449 1443 if (__get_user_pages(current, current->mm, addr, 1,
1450   - GUP_FLAGS_FORCE | GUP_FLAGS_DUMP, &page, &vma) < 1)
  1444 + FOLL_FORCE | FOLL_DUMP | FOLL_GET, &page, &vma) < 1)
1451 1445 return NULL;
1452 1446 if (page == ZERO_PAGE(0)) {
1453 1447 page_cache_release(page);
... ... @@ -166,9 +166,9 @@
166 166 VM_BUG_ON(end > vma->vm_end);
167 167 VM_BUG_ON(!rwsem_is_locked(&mm->mmap_sem));
168 168  
169   - gup_flags = 0;
  169 + gup_flags = FOLL_TOUCH | FOLL_GET;
170 170 if (vma->vm_flags & VM_WRITE)
171   - gup_flags = GUP_FLAGS_WRITE;
  171 + gup_flags |= FOLL_WRITE;
172 172  
173 173 while (nr_pages > 0) {
174 174 int i;
... ... @@ -168,20 +168,20 @@
168 168 }
169 169  
170 170 int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
171   - unsigned long start, int nr_pages, int flags,
  171 + unsigned long start, int nr_pages, int foll_flags,
172 172 struct page **pages, struct vm_area_struct **vmas)
173 173 {
174 174 struct vm_area_struct *vma;
175 175 unsigned long vm_flags;
176 176 int i;
177   - int write = !!(flags & GUP_FLAGS_WRITE);
178   - int force = !!(flags & GUP_FLAGS_FORCE);
179 177  
180 178 /* calculate required read or write permissions.
181   - * - if 'force' is set, we only require the "MAY" flags.
  179 + * If FOLL_FORCE is set, we only require the "MAY" flags.
182 180 */
183   - vm_flags = write ? (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
184   - vm_flags &= force ? (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
  181 + vm_flags = (foll_flags & FOLL_WRITE) ?
  182 + (VM_WRITE | VM_MAYWRITE) : (VM_READ | VM_MAYREAD);
  183 + vm_flags &= (foll_flags & FOLL_FORCE) ?
  184 + (VM_MAYREAD | VM_MAYWRITE) : (VM_READ | VM_WRITE);
185 185  
186 186 for (i = 0; i < nr_pages; i++) {
187 187 vma = find_vma(mm, start);
188 188  
... ... @@ -223,9 +223,9 @@
223 223 int flags = 0;
224 224  
225 225 if (write)
226   - flags |= GUP_FLAGS_WRITE;
  226 + flags |= FOLL_WRITE;
227 227 if (force)
228   - flags |= GUP_FLAGS_FORCE;
  228 + flags |= FOLL_FORCE;
229 229  
230 230 return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas);
231 231 }