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authorThomas Gleixner <tglx@linutronix.de>2012-07-15 10:24:53 +0200
committerThomas Gleixner <tglx@linutronix.de>2012-07-15 10:24:53 +0200
commite8b9dd7e2471b1274e3be719fcc385e0a710e46f (patch)
tree030d7ce20e8f8767d9423f78c102aba089eec372 /mm/madvise.c
parent924412f66fd9d21212e560a93792b0b607d46c6e (diff)
parent6b1859dba01c7d512b72d77e3fd7da8354235189 (diff)
downloadlinux-e8b9dd7e2471b1274e3be719fcc385e0a710e46f.tar.gz
Merge branch 'timers/urgent' into timers/core
Reason: Update to upstream changes to avoid further conflicts.
Fixup a trivial merge conflict in kernel/time/tick-sched.c

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'mm/madvise.c')
-rw-r--r--mm/madvise.c18
1 files changed, 14 insertions, 4 deletions
diff --git a/mm/madvise.c b/mm/madvise.c
index deff1b64a08c..14d260fa0d17 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -15,6 +15,7 @@
 #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
@@ -204,14 +205,16 @@ static long madvise_remove(struct vm_area_struct *vma,
 {
 	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;
 	}
 
@@ -221,11 +224,18 @@ static long madvise_remove(struct vm_area_struct *vma,
 	offset = (loff_t)(start - vma->vm_start)
 			+ ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
 
-	/* filesystem's fallocate may need 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 = do_fallocate(vma->vm_file,
+	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;
 }