From: Paul Mackerras [mailto:paulus@xxxxxxxxxx] > On Wed, Oct 25, 2017 at 07:39:48AM +0000, Matthew Wilcox wrote: > > Hang on, don't tell me you found this by inspection. Are you not running the > bitmap testcase, enabled by CONFIG_TEST_BITMAP? Either that should be > producing an error, or there's a missing test case, or your inspection is wrong ... > > I did find it by inspection. I was looking for a version of the > bitmap_* API that does little-endian style bitmaps on all systems, and > the inline bitmap_set() does that in the case where it calls memset, > but not in the case where it calls __bitmap_set. I do believe that you noticed it by inspection, but you shouldn't've had to. I thought we had a comprehensive set of tests for exactly this, which means that either 01.org isn't running the right set of tests on a BE system or the tests are broken. > I'll fire up a big-endian system tomorrow when I get to work to run > the test case. (PPC64 is almost entirely little-endian these days as > far as the IBM POWER systems are concerned.) > > In any case, it's pretty clearly wrong as it is. On a big-endian > 64-bit system, bitmap_set(p, 56, 16) should set bytes 0 and 15 to > 0xff, and there's no way a single memset can do that. So ... this loop should include that case, right? for (start = 0; start < 1024; start += 8) { memset(bmap1, 0x5a, sizeof(bmap1)); memset(bmap2, 0x5a, sizeof(bmap2)); for (nbits = 0; nbits < 1024 - start; nbits += 8) { bitmap_set(bmap1, start, nbits); __bitmap_set(bmap2, start, nbits); if (!bitmap_equal(bmap1, bmap2, 1024)) printk("set not equal %d %d\n", start, nbits); if (!__bitmap_equal(bmap1, bmap2, 1024)) printk("set not __equal %d %d\n", start, nbits); ��.n��������+%������w��{.n�����{��������ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f
