zsmalloc: clean up many BUG_ON
There are many BUG_ON in zsmalloc.c which is not recommened so change
them as alternatives.
Normal rule is as follows:
1. avoid BUG_ON if possible. Instead, use VM_BUG_ON or VM_BUG_ON_PAGE
2. use VM_BUG_ON_PAGE if we need to see struct page's fields
3. use those assertion in primitive functions so higher functions can
rely on the assertion in the primitive function.
4. Don't use assertion if following instruction can trigger Oops
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index c3e55a4..dfe684c 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -418,7 +418,7 @@
enum fullness_group *fullness)
{
unsigned long m;
- BUG_ON(!is_first_page(first_page));
+ VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
m = (unsigned long)first_page->mapping;
*fullness = m & FULLNESS_MASK;
@@ -430,7 +430,7 @@
enum fullness_group fullness)
{
unsigned long m;
- BUG_ON(!is_first_page(first_page));
+ VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
m = ((class_idx & CLASS_IDX_MASK) << FULLNESS_BITS) |
(fullness & FULLNESS_MASK);
@@ -631,7 +631,8 @@
{
int inuse, max_objects;
enum fullness_group fg;
- BUG_ON(!is_first_page(first_page));
+
+ VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
inuse = first_page->inuse;
max_objects = first_page->objects;
@@ -659,7 +660,7 @@
{
struct page **head;
- BUG_ON(!is_first_page(first_page));
+ VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
if (fullness >= _ZS_NR_FULLNESS_GROUPS)
return;
@@ -691,13 +692,13 @@
{
struct page **head;
- BUG_ON(!is_first_page(first_page));
+ VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
if (fullness >= _ZS_NR_FULLNESS_GROUPS)
return;
head = &class->fullness_list[fullness];
- BUG_ON(!*head);
+ VM_BUG_ON_PAGE(!*head, first_page);
if (list_empty(&(*head)->lru))
*head = NULL;
else if (*head == first_page)
@@ -724,8 +725,6 @@
int class_idx;
enum fullness_group currfg, newfg;
- BUG_ON(!is_first_page(first_page));
-
get_zspage_mapping(first_page, &class_idx, &currfg);
newfg = get_fullness_group(first_page);
if (newfg == currfg)
@@ -811,7 +810,7 @@
unsigned long obj;
if (!page) {
- BUG_ON(obj_idx);
+ VM_BUG_ON(obj_idx);
return NULL;
}
@@ -844,7 +843,7 @@
void *obj)
{
if (class->huge) {
- VM_BUG_ON(!is_first_page(page));
+ VM_BUG_ON_PAGE(!is_first_page(page), page);
return page_private(page);
} else
return *(unsigned long *)obj;
@@ -894,8 +893,8 @@
{
struct page *nextp, *tmp, *head_extra;
- BUG_ON(!is_first_page(first_page));
- BUG_ON(first_page->inuse);
+ VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
+ VM_BUG_ON_PAGE(first_page->inuse, first_page);
head_extra = (struct page *)page_private(first_page);
@@ -921,7 +920,8 @@
unsigned long off = 0;
struct page *page = first_page;
- BUG_ON(!is_first_page(first_page));
+ VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
+
while (page) {
struct page *next_page;
struct link_free *link;
@@ -1238,7 +1238,7 @@
static bool zspage_full(struct page *first_page)
{
- BUG_ON(!is_first_page(first_page));
+ VM_BUG_ON_PAGE(!is_first_page(first_page), first_page);
return first_page->inuse == first_page->objects;
}
@@ -1276,14 +1276,12 @@
struct page *pages[2];
void *ret;
- BUG_ON(!handle);
-
/*
* Because we use per-cpu mapping areas shared among the
* pools/users, we can't allow mapping in interrupt context
* because it can corrupt another users mappings.
*/
- BUG_ON(in_interrupt());
+ WARN_ON_ONCE(in_interrupt());
/* From now on, migration cannot move the object */
pin_tag(handle);
@@ -1327,8 +1325,6 @@
struct size_class *class;
struct mapping_area *area;
- BUG_ON(!handle);
-
obj = handle_to_obj(handle);
obj_to_location(obj, &page, &obj_idx);
get_zspage_mapping(get_first_page(page), &class_idx, &fg);
@@ -1448,8 +1444,6 @@
unsigned long f_objidx, f_offset;
void *vaddr;
- BUG_ON(!obj);
-
obj &= ~OBJ_ALLOCATED_TAG;
obj_to_location(obj, &f_page, &f_objidx);
first_page = get_first_page(f_page);
@@ -1549,7 +1543,6 @@
kunmap_atomic(d_addr);
kunmap_atomic(s_addr);
s_page = get_next_page(s_page);
- BUG_ON(!s_page);
s_addr = kmap_atomic(s_page);
d_addr = kmap_atomic(d_page);
s_size = class->size - written;
@@ -1559,7 +1552,6 @@
if (d_off >= PAGE_SIZE) {
kunmap_atomic(d_addr);
d_page = get_next_page(d_page);
- BUG_ON(!d_page);
d_addr = kmap_atomic(d_page);
d_size = class->size - written;
d_off = 0;
@@ -1694,8 +1686,6 @@
{
enum fullness_group fullness;
- BUG_ON(!is_first_page(first_page));
-
fullness = get_fullness_group(first_page);
insert_zspage(first_page, class, fullness);
set_zspage_mapping(first_page, class->index, fullness);
@@ -1759,8 +1749,6 @@
spin_lock(&class->lock);
while ((src_page = isolate_source_page(class))) {
- BUG_ON(!is_first_page(src_page));
-
if (!zs_can_compact(class))
break;
