phy: rockchip-inno-usb2: support phy default parameters tunning.
[firefly-linux-kernel-4.4.55.git] / mm / mlock.c
index 79b7cf7d1bca72cee9babfb60e21a38799c8eba1..d843bc9d32ddb077aa4aadfb156a4e2017ee94d5 100644 (file)
@@ -11,6 +11,7 @@
 #include <linux/swap.h>
 #include <linux/swapops.h>
 #include <linux/pagemap.h>
+#include <linux/pagevec.h>
 #include <linux/mempolicy.h>
 #include <linux/syscalls.h>
 #include <linux/sched.h>
 #include <linux/rmap.h>
 #include <linux/mmzone.h>
 #include <linux/hugetlb.h>
+#include <linux/memcontrol.h>
+#include <linux/mm_inline.h>
 
 #include "internal.h"
 
 int can_do_mlock(void)
 {
-       if (capable(CAP_IPC_LOCK))
-               return 1;
        if (rlimit(RLIMIT_MEMLOCK) != 0)
                return 1;
+       if (capable(CAP_IPC_LOCK))
+               return 1;
        return 0;
 }
 EXPORT_SYMBOL(can_do_mlock);
@@ -76,6 +79,7 @@ void clear_page_mlock(struct page *page)
  */
 void mlock_vma_page(struct page *page)
 {
+       /* Serialize with page migration */
        BUG_ON(!PageLocked(page));
 
        if (!TestSetPageMlocked(page)) {
@@ -87,9 +91,73 @@ void mlock_vma_page(struct page *page)
        }
 }
 
+/*
+ * Isolate a page from LRU with optional get_page() pin.
+ * Assumes lru_lock already held and page already pinned.
+ */
+static bool __munlock_isolate_lru_page(struct page *page, bool getpage)
+{
+       if (PageLRU(page)) {
+               struct lruvec *lruvec;
+
+               lruvec = mem_cgroup_page_lruvec(page, page_zone(page));
+               if (getpage)
+                       get_page(page);
+               ClearPageLRU(page);
+               del_page_from_lru_list(page, lruvec, page_lru(page));
+               return true;
+       }
+
+       return false;
+}
+
+/*
+ * Finish munlock after successful page isolation
+ *
+ * Page must be locked. This is a wrapper for try_to_munlock()
+ * and putback_lru_page() with munlock accounting.
+ */
+static void __munlock_isolated_page(struct page *page)
+{
+       int ret = SWAP_AGAIN;
+
+       /*
+        * Optimization: if the page was mapped just once, that's our mapping
+        * and we don't need to check all the other vmas.
+        */
+       if (page_mapcount(page) > 1)
+               ret = try_to_munlock(page);
+
+       /* Did try_to_unlock() succeed or punt? */
+       if (ret != SWAP_MLOCK)
+               count_vm_event(UNEVICTABLE_PGMUNLOCKED);
+
+       putback_lru_page(page);
+}
+
+/*
+ * Accounting for page isolation fail during munlock
+ *
+ * Performs accounting when page isolation fails in munlock. There is nothing
+ * else to do because it means some other task has already removed the page
+ * from the LRU. putback_lru_page() will take care of removing the page from
+ * the unevictable list, if necessary. vmscan [page_referenced()] will move
+ * the page back to the unevictable list if some other vma has it mlocked.
+ */
+static void __munlock_isolation_failed(struct page *page)
+{
+       if (PageUnevictable(page))
+               __count_vm_event(UNEVICTABLE_PGSTRANDED);
+       else
+               __count_vm_event(UNEVICTABLE_PGMUNLOCKED);
+}
+
 /**
  * munlock_vma_page - munlock a vma page
- * @page - page to be unlocked
+ * @page - page to be unlocked, either a normal page or THP page head
+ *
+ * returns the size of the page as a page mask (0 for normal page,
+ *         HPAGE_PMD_NR - 1 for THP head page)
  *
  * called from munlock()/munmap() path with page supposedly on the LRU.
  * When we munlock a page, because the vma where we found the page is being
@@ -104,109 +172,233 @@ void mlock_vma_page(struct page *page)
  */
 unsigned int munlock_vma_page(struct page *page)
 {
-       unsigned int page_mask = 0;
+       int nr_pages;
+       struct zone *zone = page_zone(page);
 
+       /* For try_to_munlock() and to serialize with page migration */
        BUG_ON(!PageLocked(page));
 
-       if (TestClearPageMlocked(page)) {
-               unsigned int nr_pages = hpage_nr_pages(page);
-               mod_zone_page_state(page_zone(page), NR_MLOCK, -nr_pages);
-               page_mask = nr_pages - 1;
-               if (!isolate_lru_page(page)) {
-                       int ret = SWAP_AGAIN;
+       /*
+        * Serialize with any parallel __split_huge_page_refcount() which
+        * might otherwise copy PageMlocked to part of the tail pages before
+        * we clear it in the head page. It also stabilizes hpage_nr_pages().
+        */
+       spin_lock_irq(&zone->lru_lock);
 
-                       /*
-                        * Optimization: if the page was mapped just once,
-                        * that's our mapping and we don't need to check all the
-                        * other vmas.
-                        */
-                       if (page_mapcount(page) > 1)
-                               ret = try_to_munlock(page);
-                       /*
-                        * did try_to_unlock() succeed or punt?
-                        */
-                       if (ret != SWAP_MLOCK)
-                               count_vm_event(UNEVICTABLE_PGMUNLOCKED);
+       nr_pages = hpage_nr_pages(page);
+       if (!TestClearPageMlocked(page))
+               goto unlock_out;
 
-                       putback_lru_page(page);
-               } else {
-                       /*
-                        * Some other task has removed the page from the LRU.
-                        * putback_lru_page() will take care of removing the
-                        * page from the unevictable list, if necessary.
-                        * vmscan [page_referenced()] will move the page back
-                        * to the unevictable list if some other vma has it
-                        * mlocked.
-                        */
-                       if (PageUnevictable(page))
-                               count_vm_event(UNEVICTABLE_PGSTRANDED);
-                       else
-                               count_vm_event(UNEVICTABLE_PGMUNLOCKED);
-               }
+       __mod_zone_page_state(zone, NR_MLOCK, -nr_pages);
+
+       if (__munlock_isolate_lru_page(page, true)) {
+               spin_unlock_irq(&zone->lru_lock);
+               __munlock_isolated_page(page);
+               goto out;
        }
+       __munlock_isolation_failed(page);
+
+unlock_out:
+       spin_unlock_irq(&zone->lru_lock);
 
-       return page_mask;
+out:
+       return nr_pages - 1;
 }
 
-/**
- * __mlock_vma_pages_range() -  mlock a range of pages in the vma.
- * @vma:   target vma
- * @start: start address
- * @end:   end address
- *
- * This takes care of making the pages present too.
+/*
+ * convert get_user_pages() return value to posix mlock() error
+ */
+static int __mlock_posix_error_return(long retval)
+{
+       if (retval == -EFAULT)
+               retval = -ENOMEM;
+       else if (retval == -ENOMEM)
+               retval = -EAGAIN;
+       return retval;
+}
+
+/*
+ * Prepare page for fast batched LRU putback via putback_lru_evictable_pagevec()
  *
- * return 0 on success, negative error code on error.
+ * The fast path is available only for evictable pages with single mapping.
+ * Then we can bypass the per-cpu pvec and get better performance.
+ * when mapcount > 1 we need try_to_munlock() which can fail.
+ * when !page_evictable(), we need the full redo logic of putback_lru_page to
+ * avoid leaving evictable page in unevictable list.
  *
- * vma->vm_mm->mmap_sem must be held for at least read.
+ * In case of success, @page is added to @pvec and @pgrescued is incremented
+ * in case that the page was previously unevictable. @page is also unlocked.
  */
-long __mlock_vma_pages_range(struct vm_area_struct *vma,
-               unsigned long start, unsigned long end, int *nonblocking)
+static bool __putback_lru_fast_prepare(struct page *page, struct pagevec *pvec,
+               int *pgrescued)
 {
-       struct mm_struct *mm = vma->vm_mm;
-       unsigned long nr_pages = (end - start) / PAGE_SIZE;
-       int gup_flags;
+       VM_BUG_ON_PAGE(PageLRU(page), page);
+       VM_BUG_ON_PAGE(!PageLocked(page), page);
+
+       if (page_mapcount(page) <= 1 && page_evictable(page)) {
+               pagevec_add(pvec, page);
+               if (TestClearPageUnevictable(page))
+                       (*pgrescued)++;
+               unlock_page(page);
+               return true;
+       }
 
-       VM_BUG_ON(start & ~PAGE_MASK);
-       VM_BUG_ON(end   & ~PAGE_MASK);
-       VM_BUG_ON(start < vma->vm_start);
-       VM_BUG_ON(end   > vma->vm_end);
-       VM_BUG_ON(!rwsem_is_locked(&mm->mmap_sem));
+       return false;
+}
 
-       gup_flags = FOLL_TOUCH | FOLL_MLOCK;
+/*
+ * Putback multiple evictable pages to the LRU
+ *
+ * Batched putback of evictable pages that bypasses the per-cpu pvec. Some of
+ * the pages might have meanwhile become unevictable but that is OK.
+ */
+static void __putback_lru_fast(struct pagevec *pvec, int pgrescued)
+{
+       count_vm_events(UNEVICTABLE_PGMUNLOCKED, pagevec_count(pvec));
        /*
-        * We want to touch writable mappings with a write fault in order
-        * to break COW, except for shared mappings because these don't COW
-        * and we would not want to dirty them for nothing.
+        *__pagevec_lru_add() calls release_pages() so we don't call
+        * put_page() explicitly
         */
-       if ((vma->vm_flags & (VM_WRITE | VM_SHARED)) == VM_WRITE)
-               gup_flags |= FOLL_WRITE;
+       __pagevec_lru_add(pvec);
+       count_vm_events(UNEVICTABLE_PGRESCUED, pgrescued);
+}
 
-       /*
-        * We want mlock to succeed for regions that have any permissions
-        * other than PROT_NONE.
-        */
-       if (vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC))
-               gup_flags |= FOLL_FORCE;
+/*
+ * Munlock a batch of pages from the same zone
+ *
+ * The work is split to two main phases. First phase clears the Mlocked flag
+ * and attempts to isolate the pages, all under a single zone lru lock.
+ * The second phase finishes the munlock only for pages where isolation
+ * succeeded.
+ *
+ * Note that the pagevec may be modified during the process.
+ */
+static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone)
+{
+       int i;
+       int nr = pagevec_count(pvec);
+       int delta_munlocked;
+       struct pagevec pvec_putback;
+       int pgrescued = 0;
+
+       pagevec_init(&pvec_putback, 0);
+
+       /* Phase 1: page isolation */
+       spin_lock_irq(&zone->lru_lock);
+       for (i = 0; i < nr; i++) {
+               struct page *page = pvec->pages[i];
+
+               if (TestClearPageMlocked(page)) {
+                       /*
+                        * We already have pin from follow_page_mask()
+                        * so we can spare the get_page() here.
+                        */
+                       if (__munlock_isolate_lru_page(page, false))
+                               continue;
+                       else
+                               __munlock_isolation_failed(page);
+               }
+
+               /*
+                * We won't be munlocking this page in the next phase
+                * but we still need to release the follow_page_mask()
+                * pin. We cannot do it under lru_lock however. If it's
+                * the last pin, __page_cache_release() would deadlock.
+                */
+               pagevec_add(&pvec_putback, pvec->pages[i]);
+               pvec->pages[i] = NULL;
+       }
+       delta_munlocked = -nr + pagevec_count(&pvec_putback);
+       __mod_zone_page_state(zone, NR_MLOCK, delta_munlocked);
+       spin_unlock_irq(&zone->lru_lock);
+
+       /* Now we can release pins of pages that we are not munlocking */
+       pagevec_release(&pvec_putback);
+
+       /* Phase 2: page munlock */
+       for (i = 0; i < nr; i++) {
+               struct page *page = pvec->pages[i];
+
+               if (page) {
+                       lock_page(page);
+                       if (!__putback_lru_fast_prepare(page, &pvec_putback,
+                                       &pgrescued)) {
+                               /*
+                                * Slow path. We don't want to lose the last
+                                * pin before unlock_page()
+                                */
+                               get_page(page); /* for putback_lru_page() */
+                               __munlock_isolated_page(page);
+                               unlock_page(page);
+                               put_page(page); /* from follow_page_mask() */
+                       }
+               }
+       }
 
        /*
-        * We made sure addr is within a VMA, so the following will
-        * not result in a stack expansion that recurses back here.
+        * Phase 3: page putback for pages that qualified for the fast path
+        * This will also call put_page() to return pin from follow_page_mask()
         */
-       return __get_user_pages(current, mm, start, nr_pages, gup_flags,
-                               NULL, NULL, nonblocking);
+       if (pagevec_count(&pvec_putback))
+               __putback_lru_fast(&pvec_putback, pgrescued);
 }
 
 /*
- * convert get_user_pages() return value to posix mlock() error
+ * Fill up pagevec for __munlock_pagevec using pte walk
+ *
+ * The function expects that the struct page corresponding to @start address is
+ * a non-TPH page already pinned and in the @pvec, and that it belongs to @zone.
+ *
+ * The rest of @pvec is filled by subsequent pages within the same pmd and same
+ * zone, as long as the pte's are present and vm_normal_page() succeeds. These
+ * pages also get pinned.
+ *
+ * Returns the address of the next page that should be scanned. This equals
+ * @start + PAGE_SIZE when no page could be added by the pte walk.
  */
-static int __mlock_posix_error_return(long retval)
+static unsigned long __munlock_pagevec_fill(struct pagevec *pvec,
+               struct vm_area_struct *vma, int zoneid, unsigned long start,
+               unsigned long end)
 {
-       if (retval == -EFAULT)
-               retval = -ENOMEM;
-       else if (retval == -ENOMEM)
-               retval = -EAGAIN;
-       return retval;
+       pte_t *pte;
+       spinlock_t *ptl;
+
+       /*
+        * Initialize pte walk starting at the already pinned page where we
+        * are sure that there is a pte, as it was pinned under the same
+        * mmap_sem write op.
+        */
+       pte = get_locked_pte(vma->vm_mm, start, &ptl);
+       /* Make sure we do not cross the page table boundary */
+       end = pgd_addr_end(start, end);
+       end = pud_addr_end(start, end);
+       end = pmd_addr_end(start, end);
+
+       /* The page next to the pinned page is the first we will try to get */
+       start += PAGE_SIZE;
+       while (start < end) {
+               struct page *page = NULL;
+               pte++;
+               if (pte_present(*pte))
+                       page = vm_normal_page(vma, start, *pte);
+               /*
+                * Break if page could not be obtained or the page's node+zone does not
+                * match
+                */
+               if (!page || page_zone_id(page) != zoneid)
+                       break;
+
+               get_page(page);
+               /*
+                * Increase the address that will be returned *before* the
+                * eventual break due to pvec becoming full by adding the page
+                */
+               start += PAGE_SIZE;
+               if (pagevec_add(pvec, page) == 0)
+                       break;
+       }
+       pte_unmap_unlock(pte, ptl);
+       return start;
 }
 
 /*
@@ -230,12 +422,17 @@ static int __mlock_posix_error_return(long retval)
 void munlock_vma_pages_range(struct vm_area_struct *vma,
                             unsigned long start, unsigned long end)
 {
-       vma->vm_flags &= ~VM_LOCKED;
+       vma->vm_flags &= VM_LOCKED_CLEAR_MASK;
 
        while (start < end) {
-               struct page *page;
-               unsigned int page_mask, page_increm;
-
+               struct page *page = NULL;
+               unsigned int page_mask;
+               unsigned long page_increm;
+               struct pagevec pvec;
+               struct zone *zone;
+               int zoneid;
+
+               pagevec_init(&pvec, 0);
                /*
                 * Although FOLL_DUMP is intended for get_dump_page(),
                 * it just so happens that its special treatment of the
@@ -244,21 +441,47 @@ void munlock_vma_pages_range(struct vm_area_struct *vma,
                 * has sneaked into the range, we won't oops here: great).
                 */
                page = follow_page_mask(vma, start, FOLL_GET | FOLL_DUMP,
-                                       &page_mask);
+                               &page_mask);
+
                if (page && !IS_ERR(page)) {
-                       lock_page(page);
-                       lru_add_drain();
-                       /*
-                        * Any THP page found by follow_page_mask() may have
-                        * gotten split before reaching munlock_vma_page(),
-                        * so we need to recompute the page_mask here.
-                        */
-                       page_mask = munlock_vma_page(page);
-                       unlock_page(page);
-                       put_page(page);
+                       if (PageTransHuge(page)) {
+                               lock_page(page);
+                               /*
+                                * Any THP page found by follow_page_mask() may
+                                * have gotten split before reaching
+                                * munlock_vma_page(), so we need to recompute
+                                * the page_mask here.
+                                */
+                               page_mask = munlock_vma_page(page);
+                               unlock_page(page);
+                               put_page(page); /* follow_page_mask() */
+                       } else {
+                               /*
+                                * Non-huge pages are handled in batches via
+                                * pagevec. The pin from follow_page_mask()
+                                * prevents them from collapsing by THP.
+                                */
+                               pagevec_add(&pvec, page);
+                               zone = page_zone(page);
+                               zoneid = page_zone_id(page);
+
+                               /*
+                                * Try to fill the rest of pagevec using fast
+                                * pte walk. This will also update start to
+                                * the next page to process. Then munlock the
+                                * pagevec.
+                                */
+                               start = __munlock_pagevec_fill(&pvec, vma,
+                                               zoneid, start, end);
+                               __munlock_pagevec(&pvec, zone);
+                               goto next;
+                       }
                }
-               page_increm = 1 + (~(start >> PAGE_SHIFT) & page_mask);
+               /* It's a bug to munlock in the middle of a THP page */
+               VM_BUG_ON((start >> PAGE_SHIFT) & page_mask);
+               page_increm = 1 + page_mask;
                start += page_increm * PAGE_SIZE;
+next:
                cond_resched();
        }
 }
@@ -283,11 +506,13 @@ static int mlock_fixup(struct vm_area_struct *vma, struct vm_area_struct **prev,
 
        if (newflags == vma->vm_flags || (vma->vm_flags & VM_SPECIAL) ||
            is_vm_hugetlb_page(vma) || vma == get_gate_vma(current->mm))
-               goto out;       /* don't set VM_LOCKED,  don't count */
+               /* don't set VM_LOCKED or VM_LOCKONFAULT and don't count */
+               goto out;
 
        pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
        *prev = vma_merge(mm, *prev, start, end, newflags, vma->anon_vma,
-                         vma->vm_file, pgoff, vma_policy(vma));
+                         vma->vm_file, pgoff, vma_policy(vma),
+                         vma->vm_userfaultfd_ctx, vma_get_anon_name(vma));
        if (*prev) {
                vma = *prev;
                goto success;
@@ -317,7 +542,7 @@ success:
        /*
         * vm_flags is protected by the mmap_sem held in write mode.
         * It's okay if try_to_unmap_one unmaps a page just after we
-        * set VM_LOCKED, __mlock_vma_pages_range will bring it back.
+        * set VM_LOCKED, populate_vma_page_range will bring it back.
         */
 
        if (lock)
@@ -330,13 +555,14 @@ out:
        return ret;
 }
 
-static int do_mlock(unsigned long start, size_t len, int on)
+static int apply_vma_lock_flags(unsigned long start, size_t len,
+                               vm_flags_t flags)
 {
        unsigned long nstart, end, tmp;
        struct vm_area_struct * vma, * prev;
        int error;
 
-       VM_BUG_ON(start & ~PAGE_MASK);
+       VM_BUG_ON(offset_in_page(start));
        VM_BUG_ON(len != PAGE_ALIGN(len));
        end = start + len;
        if (end < start)
@@ -352,14 +578,11 @@ static int do_mlock(unsigned long start, size_t len, int on)
                prev = vma;
 
        for (nstart = start ; ; ) {
-               vm_flags_t newflags;
+               vm_flags_t newflags = vma->vm_flags & VM_LOCKED_CLEAR_MASK;
 
-               /* Here we know that  vma->vm_start <= nstart < vma->vm_end. */
-
-               newflags = vma->vm_flags & ~VM_LOCKED;
-               if (on)
-                       newflags |= VM_LOCKED;
+               newflags |= flags;
 
+               /* Here we know that  vma->vm_start <= nstart < vma->vm_end. */
                tmp = vma->vm_end;
                if (tmp > end)
                        tmp = end;
@@ -381,70 +604,7 @@ static int do_mlock(unsigned long start, size_t len, int on)
        return error;
 }
 
-/*
- * __mm_populate - populate and/or mlock pages within a range of address space.
- *
- * This is used to implement mlock() and the MAP_POPULATE / MAP_LOCKED mmap
- * flags. VMAs must be already marked with the desired vm_flags, and
- * mmap_sem must not be held.
- */
-int __mm_populate(unsigned long start, unsigned long len, int ignore_errors)
-{
-       struct mm_struct *mm = current->mm;
-       unsigned long end, nstart, nend;
-       struct vm_area_struct *vma = NULL;
-       int locked = 0;
-       long ret = 0;
-
-       VM_BUG_ON(start & ~PAGE_MASK);
-       VM_BUG_ON(len != PAGE_ALIGN(len));
-       end = start + len;
-
-       for (nstart = start; nstart < end; nstart = nend) {
-               /*
-                * We want to fault in pages for [nstart; end) address range.
-                * Find first corresponding VMA.
-                */
-               if (!locked) {
-                       locked = 1;
-                       down_read(&mm->mmap_sem);
-                       vma = find_vma(mm, nstart);
-               } else if (nstart >= vma->vm_end)
-                       vma = vma->vm_next;
-               if (!vma || vma->vm_start >= end)
-                       break;
-               /*
-                * Set [nstart; nend) to intersection of desired address
-                * range with the first VMA. Also, skip undesirable VMA types.
-                */
-               nend = min(end, vma->vm_end);
-               if (vma->vm_flags & (VM_IO | VM_PFNMAP))
-                       continue;
-               if (nstart < vma->vm_start)
-                       nstart = vma->vm_start;
-               /*
-                * Now fault in a range of pages. __mlock_vma_pages_range()
-                * double checks the vma flags, so that it won't mlock pages
-                * if the vma was already munlocked.
-                */
-               ret = __mlock_vma_pages_range(vma, nstart, nend, &locked);
-               if (ret < 0) {
-                       if (ignore_errors) {
-                               ret = 0;
-                               continue;       /* continue at next VMA */
-                       }
-                       ret = __mlock_posix_error_return(ret);
-                       break;
-               }
-               nend = nstart + ret * PAGE_SIZE;
-               ret = 0;
-       }
-       if (locked)
-               up_read(&mm->mmap_sem);
-       return ret;     /* 0 or negative error code */
-}
-
-SYSCALL_DEFINE2(mlock, unsigned long, start, size_t, len)
+static int do_mlock(unsigned long start, size_t len, vm_flags_t flags)
 {
        unsigned long locked;
        unsigned long lock_limit;
@@ -455,57 +615,104 @@ SYSCALL_DEFINE2(mlock, unsigned long, start, size_t, len)
 
        lru_add_drain_all();    /* flush pagevec */
 
-       down_write(&current->mm->mmap_sem);
-       len = PAGE_ALIGN(len + (start & ~PAGE_MASK));
+       len = PAGE_ALIGN(len + (offset_in_page(start)));
        start &= PAGE_MASK;
 
-       locked = len >> PAGE_SHIFT;
-       locked += current->mm->locked_vm;
-
        lock_limit = rlimit(RLIMIT_MEMLOCK);
        lock_limit >>= PAGE_SHIFT;
+       locked = len >> PAGE_SHIFT;
+
+       down_write(&current->mm->mmap_sem);
+
+       locked += current->mm->locked_vm;
 
        /* check against resource limits */
        if ((locked <= lock_limit) || capable(CAP_IPC_LOCK))
-               error = do_mlock(start, len, 1);
+               error = apply_vma_lock_flags(start, len, flags);
+
        up_write(&current->mm->mmap_sem);
-       if (!error)
-               error = __mm_populate(start, len, 0);
-       return error;
+       if (error)
+               return error;
+
+       error = __mm_populate(start, len, 0);
+       if (error)
+               return __mlock_posix_error_return(error);
+       return 0;
+}
+
+SYSCALL_DEFINE2(mlock, unsigned long, start, size_t, len)
+{
+       return do_mlock(start, len, VM_LOCKED);
+}
+
+SYSCALL_DEFINE3(mlock2, unsigned long, start, size_t, len, int, flags)
+{
+       vm_flags_t vm_flags = VM_LOCKED;
+
+       if (flags & ~MLOCK_ONFAULT)
+               return -EINVAL;
+
+       if (flags & MLOCK_ONFAULT)
+               vm_flags |= VM_LOCKONFAULT;
+
+       return do_mlock(start, len, vm_flags);
 }
 
 SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, len)
 {
        int ret;
 
-       down_write(&current->mm->mmap_sem);
-       len = PAGE_ALIGN(len + (start & ~PAGE_MASK));
+       len = PAGE_ALIGN(len + (offset_in_page(start)));
        start &= PAGE_MASK;
-       ret = do_mlock(start, len, 0);
+
+       down_write(&current->mm->mmap_sem);
+       ret = apply_vma_lock_flags(start, len, 0);
        up_write(&current->mm->mmap_sem);
+
        return ret;
 }
 
-static int do_mlockall(int flags)
+/*
+ * Take the MCL_* flags passed into mlockall (or 0 if called from munlockall)
+ * and translate into the appropriate modifications to mm->def_flags and/or the
+ * flags for all current VMAs.
+ *
+ * There are a couple of subtleties with this.  If mlockall() is called multiple
+ * times with different flags, the values do not necessarily stack.  If mlockall
+ * is called once including the MCL_FUTURE flag and then a second time without
+ * it, VM_LOCKED and VM_LOCKONFAULT will be cleared from mm->def_flags.
+ */
+static int apply_mlockall_flags(int flags)
 {
        struct vm_area_struct * vma, * prev = NULL;
+       vm_flags_t to_add = 0;
 
-       if (flags & MCL_FUTURE)
+       current->mm->def_flags &= VM_LOCKED_CLEAR_MASK;
+       if (flags & MCL_FUTURE) {
                current->mm->def_flags |= VM_LOCKED;
-       else
-               current->mm->def_flags &= ~VM_LOCKED;
-       if (flags == MCL_FUTURE)
-               goto out;
+
+               if (flags & MCL_ONFAULT)
+                       current->mm->def_flags |= VM_LOCKONFAULT;
+
+               if (!(flags & MCL_CURRENT))
+                       goto out;
+       }
+
+       if (flags & MCL_CURRENT) {
+               to_add |= VM_LOCKED;
+               if (flags & MCL_ONFAULT)
+                       to_add |= VM_LOCKONFAULT;
+       }
 
        for (vma = current->mm->mmap; vma ; vma = prev->vm_next) {
                vm_flags_t newflags;
 
-               newflags = vma->vm_flags & ~VM_LOCKED;
-               if (flags & MCL_CURRENT)
-                       newflags |= VM_LOCKED;
+               newflags = vma->vm_flags & VM_LOCKED_CLEAR_MASK;
+               newflags |= to_add;
 
                /* Ignore errors */
                mlock_fixup(vma, &prev, vma->vm_start, vma->vm_end, newflags);
+               cond_resched_rcu_qs();
        }
 out:
        return 0;
@@ -514,31 +721,30 @@ out:
 SYSCALL_DEFINE1(mlockall, int, flags)
 {
        unsigned long lock_limit;
-       int ret = -EINVAL;
+       int ret;
 
-       if (!flags || (flags & ~(MCL_CURRENT | MCL_FUTURE)))
-               goto out;
+       if (!flags || (flags & ~(MCL_CURRENT | MCL_FUTURE | MCL_ONFAULT)))
+               return -EINVAL;
 
-       ret = -EPERM;
        if (!can_do_mlock())
-               goto out;
+               return -EPERM;
 
        if (flags & MCL_CURRENT)
                lru_add_drain_all();    /* flush pagevec */
 
-       down_write(&current->mm->mmap_sem);
-
        lock_limit = rlimit(RLIMIT_MEMLOCK);
        lock_limit >>= PAGE_SHIFT;
 
        ret = -ENOMEM;
+       down_write(&current->mm->mmap_sem);
+
        if (!(flags & MCL_CURRENT) || (current->mm->total_vm <= lock_limit) ||
            capable(CAP_IPC_LOCK))
-               ret = do_mlockall(flags);
+               ret = apply_mlockall_flags(flags);
        up_write(&current->mm->mmap_sem);
        if (!ret && (flags & MCL_CURRENT))
                mm_populate(0, TASK_SIZE);
-out:
+
        return ret;
 }
 
@@ -547,7 +753,7 @@ SYSCALL_DEFINE0(munlockall)
        int ret;
 
        down_write(&current->mm->mmap_sem);
-       ret = do_mlockall(0);
+       ret = apply_mlockall_flags(0);
        up_write(&current->mm->mmap_sem);
        return ret;
 }