Jan Beulich
2011-Dec-23 11:36 UTC
[PATCH] linux-2.6.18/blktap: ensure mmap() is called only once per region
Signed-off-by: Jan Beulich <jbeulich@suse.com>
--- a/drivers/xen/blktap/blktap.c
+++ b/drivers/xen/blktap/blktap.c
@@ -635,6 +635,7 @@ static int blktap_release(struct inode *
info->ring_ok = 0;
smp_wmb();
+ info->rings_vstart = 0;
mm = xchg(&info->mm, NULL);
if (mm)
@@ -694,7 +695,13 @@ static int blktap_mmap(struct file *filp
WPRINTK("blktap: mmap, retrieving idx failed\n");
return -ENOMEM;
}
-
+
+ if (info->rings_vstart) {
+ WPRINTK("mmap already called on filp %p (minor %d)\n",
+ filp, info->minor);
+ return -EPERM;
+ }
+
vma->vm_flags |= VM_RESERVED;
vma->vm_ops = &blktap_vm_ops;
@@ -746,6 +753,7 @@ static int blktap_mmap(struct file *filp
/* Clear any active mappings. */
zap_page_range(vma, vma->vm_start,
vma->vm_end - vma->vm_start, NULL);
+ info->rings_vstart = 0;
return -ENOMEM;
}
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