linux/mm/gup.c

601 	/* Maybe FOLL_FORCE is set to override it? */
602 	if (!(flags & FOLL_FORCE))
605 	/* But FOLL_FORCE has no effect on shared mappings */
650 /* FOLL_FORCE can write to even unwritable PUDs in COW mappings. */
696 /* FOLL_FORCE can write to even unwritable PMDs in COW mappings. */
797 /* FOLL_FORCE can write to even unwritable PTEs in COW mappings. */
1246 			if (!(gup_flags & FOLL_FORCE))
1261 		if (!(gup_flags & FOLL_FORCE))
1865 	 * Otherwise, do a read fault, and use FOLL_FORCE in case it's not
1871 		gup_flags |= FOLL_FORCE;
1921 	 *	       difference with !FOLL_FORCE, because the page is writable
1925 	 * !FOLL_FORCE: Require proper access permissions.
2023 	 * If FOLL_FORCE is set, we only require the "MAY" flags.
2027 	vm_flags &= (foll_flags & FOLL_FORCE) ?
2213 				      FOLL_FORCE | FOLL_DUMP | FOLL_GET);
2682  * (e.g. FOLL_FORCE) are not required.
3207 				       FOLL_FORCE | FOLL_PIN | FOLL_GET |