Commit d6d03f91 authored by Albert Herranz's avatar Albert Herranz Committed by Linus Torvalds
Browse files

fb_defio: redo fix for non-dirty ptes



As pointed by Nick Piggin, ->page_mkwrite provides a way to keep a page
locked until the associated PTE is marked dirty.

Re-implement the fix by using this mechanism.
Signed-off-by: default avatarAlbert Herranz <albert_herranz@yahoo.es>
Acked-by: default avatarJaya Kumar <jayakumar.lkml@gmail.com>
Acked-by: default avatarNick Piggin <npiggin@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 3f505ca4
......@@ -100,6 +100,16 @@ static int fb_deferred_io_mkwrite(struct vm_area_struct *vma,
/* protect against the workqueue changing the page list */
mutex_lock(&fbdefio->lock);
/*
* We want the page to remain locked from ->page_mkwrite until
* the PTE is marked dirty to avoid page_mkclean() being called
* before the PTE is updated, which would leave the page ignored
* by defio.
* Do this by locking the page here and informing the caller
* about it with VM_FAULT_LOCKED.
*/
lock_page(page);
/* we loop through the pagelist before adding in order
to keep the pagelist sorted */
list_for_each_entry(cur, &fbdefio->pagelist, lru) {
......@@ -121,7 +131,7 @@ page_already_added:
/* come back after delay to process the deferred IO */
schedule_delayed_work(&info->deferred_work, fbdefio->delay);
return 0;
return VM_FAULT_LOCKED;
}
static const struct vm_operations_struct fb_deferred_io_vm_ops = {
......
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