From 835c18375a16d0cb8bc56576821d23f8e66dab73 Mon Sep 17 00:00:00 2001 From: Rasmus Villemoes Date: Tue, 30 Oct 2018 15:04:59 -0700 Subject: linux/bitmap.h: handle constant zero-size bitmaps correctly [ Upstream commit 7275b097851a5e2e0dd4da039c7e96b59ac5314e ] The static inlines in bitmap.h do not handle a compile-time constant nbits==0 correctly (they dereference the passed src or dst pointers, despite only 0 words being valid to access). I had the 0-day buildbot chew on a patch [1] that would cause build failures for such cases without complaining, suggesting that we don't have any such users currently, at least for the 70 .config/arch combinations that was built. Should any turn up, make sure they use the out-of-line versions, which do handle nbits==0 correctly. This is of course not the most efficient, but it's much less churn than teaching all the static inlines an "if (zero_const_nbits())", and since we don't have any current instances, this doesn't affect existing code at all. [1] lkml.kernel.org/r/20180815085539.27485-1-linux@rasmusvillemoes.dk Link: http://lkml.kernel.org/r/20180818131623.8755-3-linux@rasmusvillemoes.dk Signed-off-by: Rasmus Villemoes Reviewed-by: Andy Shevchenko Cc: Yury Norov Cc: Rasmus Villemoes Cc: Sudeep Holla Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- include/linux/bitmap.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'include/linux/bitmap.h') diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h index 3b77588a9360..dc56304ac829 100644 --- a/include/linux/bitmap.h +++ b/include/linux/bitmap.h @@ -185,8 +185,13 @@ extern int bitmap_print_to_pagebuf(bool list, char *buf, #define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) & (BITS_PER_LONG - 1))) #define BITMAP_LAST_WORD_MASK(nbits) (~0UL >> (-(nbits) & (BITS_PER_LONG - 1))) +/* + * The static inlines below do not handle constant nbits==0 correctly, + * so make such users (should any ever turn up) call the out-of-line + * versions. + */ #define small_const_nbits(nbits) \ - (__builtin_constant_p(nbits) && (nbits) <= BITS_PER_LONG) + (__builtin_constant_p(nbits) && (nbits) <= BITS_PER_LONG && (nbits) > 0) static inline void bitmap_zero(unsigned long *dst, unsigned int nbits) { -- cgit v1.2.3 From b74d722d60354bf8a34bef72d8aa2eef40a75ddf Mon Sep 17 00:00:00 2001 From: Rasmus Villemoes Date: Tue, 30 Oct 2018 15:05:07 -0700 Subject: linux/bitmap.h: fix type of nbits in bitmap_shift_right() [ Upstream commit d9873969fa8725dc6a5a21ab788c057fd8719751 ] Most other bitmap API, including the OOL version __bitmap_shift_right, take unsigned nbits. This was accidentally left out from 2fbad29917c98. Link: http://lkml.kernel.org/r/20180818131623.8755-5-linux@rasmusvillemoes.dk Fixes: 2fbad29917c98 ("lib: bitmap: change bitmap_shift_right to take unsigned parameters") Signed-off-by: Rasmus Villemoes Reported-by: Yury Norov Reviewed-by: Andy Shevchenko Cc: Rasmus Villemoes Cc: Sudeep Holla Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- include/linux/bitmap.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/bitmap.h') diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h index dc56304ac829..dec03c0dbc21 100644 --- a/include/linux/bitmap.h +++ b/include/linux/bitmap.h @@ -321,7 +321,7 @@ static __always_inline int bitmap_weight(const unsigned long *src, unsigned int } static inline void bitmap_shift_right(unsigned long *dst, const unsigned long *src, - unsigned int shift, int nbits) + unsigned int shift, unsigned int nbits) { if (small_const_nbits(nbits)) *dst = (*src & BITMAP_LAST_WORD_MASK(nbits)) >> shift; -- cgit v1.2.3 From 33a451d9d8ba52c2ffe6c1690fc49d798868ba2a Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Wed, 1 Aug 2018 15:42:56 -0700 Subject: bitmap: Add bitmap_alloc(), bitmap_zalloc() and bitmap_free() commit c42b65e363ce97a828f81b59033c3558f8fa7f70 upstream. A lot of code become ugly because of open coding allocations for bitmaps. Introduce three helpers to allow users be more clear of intention and keep their code neat. Note, due to multiple circular dependencies we may not provide the helpers as inliners. For now we keep them exported and, perhaps, at some point in the future we will sort out header inclusion and inheritance. Signed-off-by: Andy Shevchenko Signed-off-by: Dmitry Torokhov Signed-off-by: Greg Kroah-Hartman --- include/linux/bitmap.h | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'include/linux/bitmap.h') diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h index dec03c0dbc21..26347cc717e8 100644 --- a/include/linux/bitmap.h +++ b/include/linux/bitmap.h @@ -85,6 +85,14 @@ * contain all bit positions from 0 to 'bits' - 1. */ +/* + * Allocation and deallocation of bitmap. + * Provided in lib/bitmap.c to avoid circular dependency. + */ +extern unsigned long *bitmap_alloc(unsigned int nbits, gfp_t flags); +extern unsigned long *bitmap_zalloc(unsigned int nbits, gfp_t flags); +extern void bitmap_free(const unsigned long *bitmap); + /* * lib/bitmap.c provides these functions: */ -- cgit v1.2.3