Merge tag 'remoteproc-3.5-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git...

[deliverable/linux.git] / mm / madvise.c

diff --git a/mm/madvise.c b/mm/madvise.c
index 1ccbba5b667414e717db987b85da9e0f1691268f..14d260fa0d17939a2279c244df91789cd30720e4 100644 (file)
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -11,8 +11,11 @@
 #include <linux/mempolicy.h>
 #include <linux/page-isolation.h>
 #include <linux/hugetlb.h>
+#include <linux/falloc.h>
 #include <linux/sched.h>
 #include <linux/ksm.h>
+#include <linux/fs.h>
+#include <linux/file.h>
 
 /*
  * Any behaviour which results in changes to the vma->vm_flags needs to
@@ -200,33 +203,39 @@ static long madvise_remove(struct vm_area_struct *vma,
                                struct vm_area_struct **prev,
                                unsigned long start, unsigned long end)
 {
-       struct address_space *mapping;
-       loff_t offset, endoff;
+       loff_t offset;
        int error;
+       struct file *f;
 
        *prev = NULL;   /* tell sys_madvise we drop mmap_sem */
 
        if (vma->vm_flags & (VM_LOCKED|VM_NONLINEAR|VM_HUGETLB))
                return -EINVAL;
 
-       if (!vma->vm_file || !vma->vm_file->f_mapping
-               || !vma->vm_file->f_mapping->host) {
+       f = vma->vm_file;
+
+       if (!f || !f->f_mapping || !f->f_mapping->host) {
                        return -EINVAL;
        }
 
        if ((vma->vm_flags & (VM_SHARED|VM_WRITE)) != (VM_SHARED|VM_WRITE))
                return -EACCES;
 
-       mapping = vma->vm_file->f_mapping;
-
        offset = (loff_t)(start - vma->vm_start)
                        + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
-       endoff = (loff_t)(end - vma->vm_start - 1)
-                       + ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
 
-       /* vmtruncate_range needs to take i_mutex */
+       /*
+        * Filesystem's fallocate may need to take i_mutex.  We need to
+        * explicitly grab a reference because the vma (and hence the
+        * vma's reference to the file) can go away as soon as we drop
+        * mmap_sem.
+        */
+       get_file(f);
        up_read(&current->mm->mmap_sem);
-       error = vmtruncate_range(mapping->host, offset, endoff);
+       error = do_fallocate(f,
+                               FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
+                               offset, end - start);
+       fput(f);
        down_read(&current->mm->mmap_sem);
        return error;
 }