Hello Minchan Kim,
The patch 312fcae22703: "zsmalloc: support compaction" from Apr 15,
2015, leads to the following static checker warning:
mm/zsmalloc.c:1521 obj_malloc()
warn: 'OBJ_ALLOCATED_TAG' is a shifter (not for '|=').
mm/zsmalloc.c
1510 static unsigned long obj_malloc(struct size_class *class,
1511 struct zspage *zspage, unsigned long handle)
1512 {
1513 int i, nr_page, offset;
1514 unsigned long obj;
1515 struct link_free *link;
1516
1517 struct page *m_page;
1518 unsigned long m_offset;
1519 void *vaddr;
1520
1521 handle |= OBJ_ALLOCATED_TAG;
^^^^^^^^^^^^^^^^^
It's weird to use the same define for a bit number
1522 obj = get_freeobj(zspage);
1523
1524 offset = obj * class->size;
1525 nr_page = offset >> PAGE_SHIFT;
1526 m_offset = offset & ~PAGE_MASK;
1527 m_page = get_first_page(zspage);
1528
1529 for (i = 0; i < nr_page; i++)
1530 m_page = get_next_page(m_page);
1531
1532 vaddr = kmap_atomic(m_page);
1533 link = (struct link_free *)vaddr + m_offset / sizeof(*link);
1534 set_freeobj(zspage, link->next >> OBJ_ALLOCATED_TAG);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
And also a bit shifter. TAG normally implies it is a bit and not a
shift?
1535 if (likely(!PageHugeObject(m_page)))
1536 /* record handle in the header of allocated chunk */
1537 link->handle = handle;
1538 else
1539 /* record handle to page->index */
1540 zspage->first_page->index = handle;
1541
1542 kunmap_atomic(vaddr);
1543 mod_zspage_inuse(zspage, 1);
1544 zs_stat_inc(class, OBJ_USED, 1);
1545
1546 obj = location_to_obj(m_page, obj);
1547
1548 return obj;
1549 }
regards,
dan carpenter
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