__xip_unmap() will remove the xip sparse page from the cache
and take down pte mapping, without altering the interval tree,
thus share the i_mmap_rwsem when searching for the ptes to
unmap.
Additionally, tidy up the function a bit and make variables only
local to the interval tree walk loop.
Signed-off-by: Davidlohr Bueso <dbueso@xxxxxxx>
---
mm/filemap_xip.c | 23 +++++++++--------------
1 file changed, 9 insertions(+), 14 deletions(-)
diff --git a/mm/filemap_xip.c b/mm/filemap_xip.c
index bad746b..0d105ae 100644
--- a/mm/filemap_xip.c
+++ b/mm/filemap_xip.c
@@ -155,22 +155,14 @@ xip_file_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)
EXPORT_SYMBOL_GPL(xip_file_read);
/*
- * __xip_unmap is invoked from xip_unmap and
- * xip_write
+ * __xip_unmap is invoked from xip_unmap and xip_write
*
* This function walks all vmas of the address_space and unmaps the
* __xip_sparse_page when found at pgoff.
*/
-static void
-__xip_unmap (struct address_space * mapping,
- unsigned long pgoff)
+static void __xip_unmap(struct address_space * mapping, unsigned long pgoff)
{
struct vm_area_struct *vma;
- struct mm_struct *mm;
- unsigned long address;
- pte_t *pte;
- pte_t pteval;
- spinlock_t *ptl;
struct page *page;
unsigned count;
int locked = 0;
@@ -182,11 +174,14 @@ __xip_unmap (struct address_space * mapping,
return;
retry:
- i_mmap_lock_write(mapping);
+ i_mmap_lock_read(mapping);
vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff) {
- mm = vma->vm_mm;
- address = vma->vm_start +
+ pte_t *pte, pteval;
+ spinlock_t *ptl;
+ struct mm_struct *mm = vma->vm_mm;
+ unsigned long address = vma->vm_start +
((pgoff - vma->vm_pgoff) << PAGE_SHIFT);
+
BUG_ON(address < vma->vm_start || address >= vma->vm_end);
pte = page_check_address(page, mm, address, &ptl, 1);
if (pte) {
@@ -202,7 +197,7 @@ retry:
page_cache_release(page);
}
}
- i_mmap_unlock_write(mapping);
+ i_mmap_unlock_read(mapping);
if (locked) {
mutex_unlock(&xip_sparse_mutex);
--
1.8.4.5
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