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Commit 748f1a2e authored by KOSAKI Motohiro's avatar KOSAKI Motohiro Committed by Linus Torvalds
Browse files

mm: remove unevictable's show_page_path 



Hugh Dickins reported show_page_path() is buggy and unsafe because

 - lack dput() against d_find_alias()
 - don't concern vma->vm_mm->owner == NULL
 - lack lock_page()

it was only for debugging, so rather than trying to fix it, just remove
it now.

Reported-by: default avatarHugh Dickins <hugh@veritas.com>
Signed-off-by: default avatarHugh Dickins <hugh@veritas.com>
Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
CC: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
CC: Rik van Riel <riel@redhat.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent fb751098

mm/vmscan.c

+0 −35
Original line number Diff line number Diff line
@@ -2368,39 +2368,6 @@ int page_evictable(struct page *page, struct vm_area_struct *vma) 
	return 1;

}



static void show_page_path(struct page *page)

{

	char buf[256];

	if (page_is_file_cache(page)) {

		struct address_space *mapping = page->mapping;

		struct dentry *dentry;

		pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);



		spin_lock(&mapping->i_mmap_lock);

		dentry = d_find_alias(mapping->host);

		printk(KERN_INFO "rescued: %s %lu\n",

		       dentry_path(dentry, buf, 256), pgoff);

		spin_unlock(&mapping->i_mmap_lock);

	} else {

#if defined(CONFIG_MM_OWNER) && defined(CONFIG_MMU)

		struct anon_vma *anon_vma;

		struct vm_area_struct *vma;



		anon_vma = page_lock_anon_vma(page);

		if (!anon_vma)

			return;



		list_for_each_entry(vma, &anon_vma->head, anon_vma_node) {

			printk(KERN_INFO "rescued: anon %s\n",

			       vma->vm_mm->owner->comm);

			break;

		}

		page_unlock_anon_vma(anon_vma);

#endif

	}

}





/**

 * check_move_unevictable_page - check page for evictability and move to appropriate zone lru list

 * @page: page to check evictability and move to appropriate lru list
@@ -2421,8 +2388,6 @@ static void check_move_unevictable_page(struct page *page, struct zone *zone) 
	if (page_evictable(page, NULL)) {

		enum lru_list l = LRU_INACTIVE_ANON + page_is_file_cache(page);



		show_page_path(page);



		__dec_zone_state(zone, NR_UNEVICTABLE);

		list_move(&page->lru, &zone->lru[l].list);

		__inc_zone_state(zone, NR_INACTIVE_ANON + l);