mm: replace some BUG_ONs by VM_BUG_ONs
The swap code is over-provisioned with BUG_ONs on assorted page flags,
mostly dating back to 2.3. They're good documentation, and guard against
developer error, but a waste of space on most systems: change them to
VM_BUG_ONs, conditional on CONFIG_DEBUG_VM. Just delete the PagePrivate
ones: they're later, from 2.5.69, but even less interesting now.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/page_io.c b/mm/page_io.c
index 065c448..d277a80 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c
@@ -125,8 +125,8 @@
struct bio *bio;
int ret = 0;
- BUG_ON(!PageLocked(page));
- BUG_ON(PageUptodate(page));
+ VM_BUG_ON(!PageLocked(page));
+ VM_BUG_ON(PageUptodate(page));
bio = get_swap_bio(GFP_KERNEL, page_private(page), page,
end_swap_bio_read);
if (bio == NULL) {
diff --git a/mm/swap_state.c b/mm/swap_state.c
index 3353c90..e793fde 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -72,10 +72,10 @@
{
int error;
- BUG_ON(!PageLocked(page));
- BUG_ON(PageSwapCache(page));
- BUG_ON(PagePrivate(page));
- BUG_ON(!PageSwapBacked(page));
+ VM_BUG_ON(!PageLocked(page));
+ VM_BUG_ON(PageSwapCache(page));
+ VM_BUG_ON(!PageSwapBacked(page));
+
error = radix_tree_preload(gfp_mask);
if (!error) {
page_cache_get(page);
@@ -108,10 +108,9 @@
*/
void __delete_from_swap_cache(struct page *page)
{
- BUG_ON(!PageLocked(page));
- BUG_ON(!PageSwapCache(page));
- BUG_ON(PageWriteback(page));
- BUG_ON(PagePrivate(page));
+ VM_BUG_ON(!PageLocked(page));
+ VM_BUG_ON(!PageSwapCache(page));
+ VM_BUG_ON(PageWriteback(page));
radix_tree_delete(&swapper_space.page_tree, page_private(page));
set_page_private(page, 0);
@@ -134,8 +133,8 @@
swp_entry_t entry;
int err;
- BUG_ON(!PageLocked(page));
- BUG_ON(!PageUptodate(page));
+ VM_BUG_ON(!PageLocked(page));
+ VM_BUG_ON(!PageUptodate(page));
for (;;) {
entry = get_swap_page();
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 54a9f87..214e90b 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -333,7 +333,7 @@
{
int count;
- BUG_ON(!PageLocked(page));
+ VM_BUG_ON(!PageLocked(page));
count = page_mapcount(page);
if (count <= 1 && PageSwapCache(page))
count += page_swapcount(page);
@@ -350,8 +350,7 @@
struct swap_info_struct * p;
swp_entry_t entry;
- BUG_ON(PagePrivate(page));
- BUG_ON(!PageLocked(page));
+ VM_BUG_ON(!PageLocked(page));
if (!PageSwapCache(page))
return 0;
@@ -432,7 +431,6 @@
if (page) {
int one_user;
- BUG_ON(PagePrivate(page));
one_user = (page_count(page) == 2);
/* Only cache user (+us), or swap space full? Free it! */
/* Also recheck PageSwapCache after page is locked (above) */
@@ -1209,7 +1207,7 @@
{
struct backing_dev_info *bdi;
- BUG_ON(!PageLocked(page)); /* It pins the swap_info_struct */
+ VM_BUG_ON(!PageLocked(page)); /* It pins the swap_info_struct */
if (PageSwapCache(page)) {
swp_entry_t entry = { .val = page_private(page) };
