mm: make do_mmap_pgoff return populate as a size in bytes, not as a bool

do_mmap_pgoff() rounds up the desired size to the next PAGE_SIZE
multiple, however there was no equivalent code in mm_populate(), which
caused issues.

This could be fixed by introduced the same rounding in mm_populate(),
however I think it's preferable to make do_mmap_pgoff() return populate
as a size rather than as a boolean, so we don't have to duplicate the
size rounding logic in mm_populate().

Signed-off-by: Michel Lespinasse <walken@google.com>
Acked-by: Rik van Riel <riel@redhat.com>
Tested-by: Andy Lutomirski <luto@amacapital.net>
Cc: Greg Ungerer <gregungerer@westnet.com.au>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

6 files changed, 13 insertions, 14 deletions

diff --git a/fs/aio.c b/fs/aio.c
index 82eec7c7b4bb..064bfbe37566 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -101,9 +101,8 @@ static int aio_setup_ring(struct kioctx *ctx)
         struct aio_ring *ring;
         struct aio_ring_info *info = &ctx->ring_info;
         unsigned nr_events = ctx->max_reqs;
-        unsigned long size;
+        unsigned long size, populate;
         int nr_pages;
-        bool populate;
 
         /* Compensate for the ring buffer's head/tail overlap entry */
         nr_events += 2; /* 1 is required, 2 for good luck */
@@ -150,7 +149,7 @@ static int aio_setup_ring(struct kioctx *ctx)
                 return -EAGAIN;
         }
         if (populate)
-                mm_populate(info->mmap_base, info->mmap_size);
+                mm_populate(info->mmap_base, populate);
 
         ctx->user_id = info->mmap_base;
 
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 9a5fcdeaa3a0..95db68e34b18 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1475,7 +1475,7 @@ extern unsigned long mmap_region(struct file *file, unsigned long addr,
         unsigned long len, vm_flags_t vm_flags, unsigned long pgoff);
 extern unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
         unsigned long len, unsigned long prot, unsigned long flags,
-        unsigned long pgoff, bool *populate);
+        unsigned long pgoff, unsigned long *populate);
 extern int do_munmap(struct mm_struct *, unsigned long, size_t);
 
 #ifdef CONFIG_MMU
diff --git a/ipc/shm.c b/ipc/shm.c
index 9f047ba69e62..be3ec9ae454e 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -971,7 +971,7 @@ long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr,
         struct shm_file_data *sfd;
         struct path path;
         fmode_t f_mode;
-        bool populate = false;
+        unsigned long populate = 0;
 
         err = -EINVAL;
         if (shmid < 0)
@@ -1078,7 +1078,7 @@ long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr,
 invalid:
         up_write(&current->mm->mmap_sem);
         if (populate)
-                mm_populate(addr, size);
+                mm_populate(addr, populate);
 
 out_fput:
         fput(file);
diff --git a/mm/mmap.c b/mm/mmap.c
index 39a3944e1658..44bb4d869884 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1163,13 +1163,13 @@ static inline unsigned long round_hint_to_min(unsigned long hint)
 unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
                         unsigned long len, unsigned long prot,
                         unsigned long flags, unsigned long pgoff,
-                        bool *populate)
+                        unsigned long *populate)
 {
         struct mm_struct * mm = current->mm;
         struct inode *inode;
         vm_flags_t vm_flags;
 
-        *populate = false;
+        *populate = 0;
 
         /*
          * Does the application expect PROT_READ to imply PROT_EXEC?
@@ -1307,7 +1307,7 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
 
         addr = mmap_region(file, addr, len, vm_flags, pgoff);
         if (!IS_ERR_VALUE(addr) && (vm_flags & VM_POPULATE))
-                *populate = true;
+                *populate = len;
         return addr;
 }
 
diff --git a/mm/nommu.c b/mm/nommu.c
index 7296a5a280e7..18c1b932e2c4 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1251,7 +1251,7 @@ unsigned long do_mmap_pgoff(struct file *file,
                             unsigned long prot,
                             unsigned long flags,
                             unsigned long pgoff,
-                            bool *populate)
+                            unsigned long *populate)
 {
         struct vm_area_struct *vma;
         struct vm_region *region;
@@ -1261,7 +1261,7 @@ unsigned long do_mmap_pgoff(struct file *file,
 
         kenter(",%lx,%lx,%lx,%lx,%lx", addr, len, prot, flags, pgoff);
 
-        *populate = false;
+        *populate = 0;
 
         /* decide whether we should attempt the mapping, and if so what sort of
          * mapping */
diff --git a/mm/util.c b/mm/util.c
index 13467e043e9e..3704bf1bef94 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -355,7 +355,7 @@ unsigned long vm_mmap_pgoff(struct file *file, unsigned long addr,
 {
         unsigned long ret;
         struct mm_struct *mm = current->mm;
-        bool populate;
+        unsigned long populate;
 
         ret = security_mmap_file(file, prot, flag);
         if (!ret) {
@@ -363,8 +363,8 @@ unsigned long vm_mmap_pgoff(struct file *file, unsigned long addr,
                 ret = do_mmap_pgoff(file, addr, len, prot, flag, pgoff,
                                     &populate);
                 up_write(&mm->mmap_sem);
-                if (!IS_ERR_VALUE(ret) && populate)
-                        mm_populate(ret, len);
+                if (populate)
+                        mm_populate(ret, populate);
         }
         return ret;
 }