diff options
author | Jeff Garzik <jgarzik@pretzel.yyz.us> | 2005-06-22 13:10:49 -0400 |
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committer | Jeff Garzik <jgarzik@pobox.com> | 2005-06-22 13:10:49 -0400 |
commit | 80bd6d7f5e0d872a0f5a151473d2a39d95d210a8 (patch) | |
tree | b3a36048d6b7de88f7e906624ecb4b98816bb736 /mm/rmap.c | |
parent | 949d33e70f2c3e93bfe5265a50e40175b1ab1ec1 (diff) | |
parent | 2a5a68b840cbab31baab2d9b2e1e6de3b289ae1e (diff) |
Merge /spare/repo/linux-2.6/
Diffstat (limited to 'mm/rmap.c')
-rw-r--r-- | mm/rmap.c | 21 |
1 files changed, 0 insertions, 21 deletions
diff --git a/mm/rmap.c b/mm/rmap.c index 9827409eb7c..89770bd25f3 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -539,27 +539,6 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma) goto out_unmap; } - /* - * Don't pull an anonymous page out from under get_user_pages. - * GUP carefully breaks COW and raises page count (while holding - * page_table_lock, as we have here) to make sure that the page - * cannot be freed. If we unmap that page here, a user write - * access to the virtual address will bring back the page, but - * its raised count will (ironically) be taken to mean it's not - * an exclusive swap page, do_wp_page will replace it by a copy - * page, and the user never get to see the data GUP was holding - * the original page for. - * - * This test is also useful for when swapoff (unuse_process) has - * to drop page lock: its reference to the page stops existing - * ptes from being unmapped, so swapoff can make progress. - */ - if (PageSwapCache(page) && - page_count(page) != page_mapcount(page) + 2) { - ret = SWAP_FAIL; - goto out_unmap; - } - /* Nuke the page table entry. */ flush_cache_page(vma, address, page_to_pfn(page)); pteval = ptep_clear_flush(vma, address, pte); |