Merge tag 'bitmap-6.0-rc1' of https://github.com/norov/linux

Pull bitmap updates from Yury Norov:

 - fix the duplicated comments on bitmap_to_arr64() (Qu Wenruo)

 - optimize out non-atomic bitops on compile-time constants (Alexander
   Lobakin)

 - cleanup bitmap-related headers (Yury Norov)

 - x86/olpc: fix 'logical not is only applied to the left hand side'
   (Alexander Lobakin)

 - lib/nodemask: inline wrappers around bitmap (Yury Norov)

* tag 'bitmap-6.0-rc1' of https://github.com/norov/linux: (26 commits)
  lib/nodemask: inline next_node_in() and node_random()
  powerpc: drop dependency on <asm/machdep.h> in archrandom.h
  x86/olpc: fix 'logical not is only applied to the left hand side'
  lib/cpumask: move some one-line wrappers to header file
  headers/deps: mm: align MANITAINERS and Docs with new gfp.h structure
  headers/deps: mm: Split <linux/gfp_types.h> out of <linux/gfp.h>
  headers/deps: mm: Optimize <linux/gfp.h> header dependencies
  lib/cpumask: move trivial wrappers around find_bit to the header
  lib/cpumask: change return types to unsigned where appropriate
  cpumask: change return types to bool where appropriate
  lib/bitmap: change type of bitmap_weight to unsigned long
  lib/bitmap: change return types to bool where appropriate
  arm: align find_bit declarations with generic kernel
  iommu/vt-d: avoid invalid memory access via node_online(NUMA_NO_NODE)
  lib/test_bitmap: test the tail after bitmap_to_arr64()
  lib/bitmap: fix off-by-one in bitmap_to_arr64()
  lib: test_bitmap: add compile-time optimization/evaluations assertions
  bitmap: don't assume compiler evaluates small mem*() builtins calls
  net/ice: fix initializing the bitmap in the switch code
  bitops: let optimize out non-atomic bitops on compile-time constants
  ...

1 files changed, 50 insertions, 0 deletions

diff --git a/include/linux/bitops.h b/include/linux/bitops.h
index 7aaed501f768..cf9bf65039f2 100644
--- a/include/linux/bitops.h
+++ b/include/linux/bitops.h
@@ -27,11 +27,61 @@ extern unsigned int __sw_hweight32(unsigned int w);
 extern unsigned long __sw_hweight64(__u64 w);
 
 /*
+ * Defined here because those may be needed by architecture-specific static
+ * inlines.
+ */
+
+#include <asm-generic/bitops/generic-non-atomic.h>
+
+/*
+ * Many architecture-specific non-atomic bitops contain inline asm code and due
+ * to that the compiler can't optimize them to compile-time expressions or
+ * constants. In contrary, generic_*() helpers are defined in pure C and
+ * compilers optimize them just well.
+ * Therefore, to make `unsigned long foo = 0; __set_bit(BAR, &foo)` effectively
+ * equal to `unsigned long foo = BIT(BAR)`, pick the generic C alternative when
+ * the arguments can be resolved at compile time. That expression itself is a
+ * constant and doesn't bring any functional changes to the rest of cases.
+ * The casts to `uintptr_t` are needed to mitigate `-Waddress` warnings when
+ * passing a bitmap from .bss or .data (-> `!!addr` is always true).
+ */
+#define bitop(op, nr, addr)						\
+	((__builtin_constant_p(nr) &&					\
+	  __builtin_constant_p((uintptr_t)(addr) != (uintptr_t)NULL) &&	\
+	  (uintptr_t)(addr) != (uintptr_t)NULL &&			\
+	  __builtin_constant_p(*(const unsigned long *)(addr))) ?	\
+	 const##op(nr, addr) : op(nr, addr))
+
+#define __set_bit(nr, addr)		bitop(___set_bit, nr, addr)
+#define __clear_bit(nr, addr)		bitop(___clear_bit, nr, addr)
+#define __change_bit(nr, addr)		bitop(___change_bit, nr, addr)
+#define __test_and_set_bit(nr, addr)	bitop(___test_and_set_bit, nr, addr)
+#define __test_and_clear_bit(nr, addr)	bitop(___test_and_clear_bit, nr, addr)
+#define __test_and_change_bit(nr, addr)	bitop(___test_and_change_bit, nr, addr)
+#define test_bit(nr, addr)		bitop(_test_bit, nr, addr)
+
+/*
  * Include this here because some architectures need generic_ffs/fls in
  * scope
  */
 #include <asm/bitops.h>
 
+/* Check that the bitops prototypes are sane */
+#define __check_bitop_pr(name)						\
+	static_assert(__same_type(arch_##name, generic_##name) &&	\
+		      __same_type(const_##name, generic_##name) &&	\
+		      __same_type(_##name, generic_##name))
+
+__check_bitop_pr(__set_bit);
+__check_bitop_pr(__clear_bit);
+__check_bitop_pr(__change_bit);
+__check_bitop_pr(__test_and_set_bit);
+__check_bitop_pr(__test_and_clear_bit);
+__check_bitop_pr(__test_and_change_bit);
+__check_bitop_pr(test_bit);
+
+#undef __check_bitop_pr
+
 static inline int get_bitmask_order(unsigned int count)
 {
 	int order;