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Commit 874bfcaf authored by Davidlohr Bueso's avatar Davidlohr Bueso Committed by Linus Torvalds
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mm/xip: share the i_mmap_rwsem 



__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: default avatarDavidlohr Bueso <dbueso@suse.de>
Acked-by: default avatar"Kirill A. Shutemov" <kirill@shutemov.name>
Acked-by: default avatarHugh Dickins <hughd@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: default avatarMel Gorman <mgorman@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 4a23717a

mm/filemap_xip.c

+9 −14
Original line number Diff line number Diff line
@@ -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 @@ __xip_unmap (struct address_space * mapping, 
			page_cache_release(page);

		}

	}

	i_mmap_unlock_write(mapping);

	i_mmap_unlock_read(mapping);



	if (locked) {

		mutex_unlock(&xip_sparse_mutex);