Hi Matthew, I love your patch! Perhaps something to improve: [auto build test WARNING on linus/master] [also build test WARNING on v4.15-rc3] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system] url: https://github.com/0day-ci/linux/commits/Wei-Wang/Virtio-balloon-Enhancement/20171215-100525 reproduce: # apt-get install sparse make ARCH=x86_64 allmodconfig make C=1 CF=-D__CHECK_ENDIAN__ sparse warnings: (new ones prefixed by >>) vim +29 lib/xbitmap.c 5 6 /** 7 * xb_set_bit - set a bit in the xbitmap 8 * @xb: the xbitmap tree used to record the bit 9 * @bit: index of the bit to set 10 * 11 * This function is used to set a bit in the xbitmap. If the bitmap that @bit 12 * resides in is not there, the per-cpu ida_bitmap will be taken. 13 * 14 * Returns: 0 on success. %-EAGAIN indicates that @bit was not set. 15 */ 16 int xb_set_bit(struct xb *xb, unsigned long bit) 17 { 18 int err; 19 unsigned long index = bit / IDA_BITMAP_BITS; 20 struct radix_tree_root *root = &xb->xbrt; 21 struct radix_tree_node *node; 22 void **slot; 23 struct ida_bitmap *bitmap; 24 unsigned long ebit; 25 26 bit %= IDA_BITMAP_BITS; 27 ebit = bit + 2; 28 > 29 err = __radix_tree_create(root, index, 0, &node, &slot); 30 if (err) 31 return err; 32 bitmap = rcu_dereference_raw(*slot); 33 if (radix_tree_exception(bitmap)) { 34 unsigned long tmp = (unsigned long)bitmap; 35 36 if (ebit < BITS_PER_LONG) { 37 tmp |= 1UL << ebit; 38 rcu_assign_pointer(*slot, (void *)tmp); 39 return 0; 40 } 41 bitmap = this_cpu_xchg(ida_bitmap, NULL); 42 if (!bitmap) 43 return -EAGAIN; 44 memset(bitmap, 0, sizeof(*bitmap)); 45 bitmap->bitmap[0] = tmp >> RADIX_TREE_EXCEPTIONAL_SHIFT; 46 rcu_assign_pointer(*slot, bitmap); 47 } 48 49 if (!bitmap) { 50 if (ebit < BITS_PER_LONG) { 51 bitmap = (void *)((1UL << ebit) | 52 RADIX_TREE_EXCEPTIONAL_ENTRY); > 53 __radix_tree_replace(root, node, slot, bitmap, NULL); 54 return 0; 55 } 56 bitmap = this_cpu_xchg(ida_bitmap, NULL); 57 if (!bitmap) 58 return -EAGAIN; 59 memset(bitmap, 0, sizeof(*bitmap)); 60 __radix_tree_replace(root, node, slot, bitmap, NULL); 61 } 62 63 __set_bit(bit, bitmap->bitmap); 64 return 0; 65 } 66 EXPORT_SYMBOL(xb_set_bit); 67 --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation
