Merge branch 'akpm' (patches from Andrew)

[mirror_ubuntu-artful-kernel.git] / fs / userfaultfd.c

diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 2407249998c326e178087f65eb1500954e32abf1..f7555fc25877435e13b65cbe597ae9bdb11c6528 100644 (file)
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -138,8 +138,6 @@ out:
  * userfaultfd_ctx_get - Acquires a reference to the internal userfaultfd
  * context.
  * @ctx: [in] Pointer to the userfaultfd context.
- *
- * Returns: In case of success, returns not zero.
  */
 static void userfaultfd_ctx_get(struct userfaultfd_ctx *ctx)
 {
@@ -267,6 +265,7 @@ static inline bool userfaultfd_must_wait(struct userfaultfd_ctx *ctx,
 {
        struct mm_struct *mm = ctx->mm;
        pgd_t *pgd;
+       p4d_t *p4d;
        pud_t *pud;
        pmd_t *pmd, _pmd;
        pte_t *pte;
@@ -277,7 +276,10 @@ static inline bool userfaultfd_must_wait(struct userfaultfd_ctx *ctx,
        pgd = pgd_offset(mm, address);
        if (!pgd_present(*pgd))
                goto out;
-       pud = pud_offset(pgd, address);
+       p4d = p4d_offset(pgd, address);
+       if (!p4d_present(*p4d))
+               goto out;
+       pud = pud_offset(p4d, address);
        if (!pud_present(*pud))
                goto out;
        pmd = pmd_offset(pud, address);
@@ -695,8 +697,7 @@ void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *vm_ctx,
        userfaultfd_event_wait_completion(ctx, &ewq);
 }
 
-void userfaultfd_remove(struct vm_area_struct *vma,
-                       struct vm_area_struct **prev,
+bool userfaultfd_remove(struct vm_area_struct *vma,
                        unsigned long start, unsigned long end)
 {
        struct mm_struct *mm = vma->vm_mm;
@@ -705,13 +706,11 @@ void userfaultfd_remove(struct vm_area_struct *vma,
 
        ctx = vma->vm_userfaultfd_ctx.ctx;
        if (!ctx || !(ctx->features & UFFD_FEATURE_EVENT_REMOVE))
-               return;
+               return true;
 
        userfaultfd_ctx_get(ctx);
        up_read(&mm->mmap_sem);
 
-       *prev = NULL; /* We wait for ACK w/o the mmap semaphore */
-
        msg_init(&ewq.msg);
 
        ewq.msg.event = UFFD_EVENT_REMOVE;
@@ -720,7 +719,7 @@ void userfaultfd_remove(struct vm_area_struct *vma,
 
        userfaultfd_event_wait_completion(ctx, &ewq);
 
-       down_read(&mm->mmap_sem);
+       return false;
 }
 
 static bool has_unmap_ctx(struct userfaultfd_ctx *ctx, struct list_head *unmaps,
@@ -1757,7 +1756,7 @@ static void userfaultfd_show_fdinfo(struct seq_file *m, struct file *f)
         *      protocols: aa:... bb:...
         */
        seq_printf(m, "pending:\t%lu\ntotal:\t%lu\nAPI:\t%Lx:%x:%Lx\n",
-                  pending, total, UFFD_API, UFFD_API_FEATURES,
+                  pending, total, UFFD_API, ctx->features,
                   UFFD_API_IOCTLS|UFFD_API_RANGE_IOCTLS);
 }
 #endif