+ bitmap-make-bitmap_fill-and-bitmap_zero-consistent.patch added to -mm tree

+ bitmap-make-bitmap_fill-and-bitmap_zero-consistent.patch added to -mm tree

[akpm]

The patch titled
     Subject: include/linux/bitmap.h: make bitmap_fill() and bitmap_zero() consistent
has been added to the -mm tree.  Its filename is
     bitmap-make-bitmap_fill-and-bitmap_zero-consistent.patch

This patch should soon appear at
    http://ozlabs.org/~akpm/mmots/broken-out/bitmap-make-bitmap_fill-and-bitmap_zero-consistent.patch
and later at
    http://ozlabs.org/~akpm/mmotm/broken-out/bitmap-make-bitmap_fill-and-bitmap_zero-consistent.patch

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------------------------------------------------------
From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Subject: include/linux/bitmap.h: make bitmap_fill() and bitmap_zero() consistent

Behaviour of bitmap_fill() differs from bitmap_zero() in a way how bits
behind bitmap are handed.  bitmap_zero() clears entire bitmap by unsigned
long boundary, while bitmap_fill() mimics bitmap_set().

Here we change bitmap_fill() behaviour to be consistent with bitmap_zero()
and add a note to documentation.

The change might reveal some bugs in the code where unused bits are
handled differently and in such cases bitmap_set() has to be used.

Link: http://lkml.kernel.org/r/20180109172430.87452-4-andriy.shevchenko@linux.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Suggested-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Yury Norov <ynorov@caviumnetworks.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/bitmap.h |   15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff -puN include/linux/bitmap.h~bitmap-make-bitmap_fill-and-bitmap_zero-consistent include/linux/bitmap.h
--- a/include/linux/bitmap.h~bitmap-make-bitmap_fill-and-bitmap_zero-consistent
+++ a/include/linux/bitmap.h
@@ -67,6 +67,11 @@
  *  bitmap_from_arr32(dst, buf, nbits)          Copy nbits from u32[] buf to dst
  *  bitmap_to_arr32(buf, src, nbits)            Copy nbits from buf to u32[] dst
  *
+ * Note, bitmap_zero() and bitmap_fill() operate over the region of
+ * unsigned longs, that is, bits behind bitmap till the unsigned long
+ * boundary will be zeroed or filled as well. Consider to use
+ * bitmap_clear() or bitmap_set() to make explicit zeroing or filling
+ * respectively.
  */
 
 /**
@@ -202,12 +207,12 @@ static inline void bitmap_zero(unsigned
 
 static inline void bitmap_fill(unsigned long *dst, unsigned int nbits)
 {
-	unsigned int nlongs = BITS_TO_LONGS(nbits);
-	if (!small_const_nbits(nbits)) {
-		unsigned int len = (nlongs - 1) * sizeof(unsigned long);
-		memset(dst, 0xff,  len);
+	if (small_const_nbits(nbits))
+		*dst = ~0UL;
+	else {
+		unsigned int len = BITS_TO_LONGS(nbits) * sizeof(unsigned long);
+		memset(dst, 0xff, len);
 	}
-	dst[nlongs - 1] = BITMAP_LAST_WORD_MASK(nbits);
 }
 
 static inline void bitmap_copy(unsigned long *dst, const unsigned long *src,
_

Patches currently in -mm which might be from andriy.shevchenko@linux.intel.com are

scripts-decodecode-make-it-take-multiline-code-line.patch
bitmap-add-bitmap_zero-bitmap_clear-test-cases.patch
bitmap-add-bitmap_fill-bitmap_set-test-cases.patch
bitmap-clean-up-test_zero_fill_copy-test-case-and-rename.patch
bitmap-make-bitmap_fill-and-bitmap_zero-consistent.patch