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authorKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2012-08-13 15:39:10 -0400
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2012-08-13 15:39:10 -0400
commit0980bd9cd32de2fef7eaa2858345c49d14498625 (patch)
tree41f5f823d0569a81b22037e79c22d823933a63f1 /lib/memweight.c
parent78821b2c0299ab807d483802f09897728b93bce0 (diff)
parent0d7614f09c1ebdbaa1599a5aba7593f147bf96ee (diff)
Merge commit 'v3.6-rc1' into linux-next
* commit 'v3.6-rc1': (9532 commits) Linux 3.6-rc1 mm: remove node_start_pfn checking in new WARN_ON for now ARM: mmp: add missing irqs.h arm: mvebu: fix typo in .dtsi comment for Armada XP SoCs ARM: PRIMA2: delete redundant codes to restore LATCHED when timer resumes libceph: fix crypto key null deref, memory leak ceph: simplify+fix atomic_open sh: explicitly include sh_dma.h in setup-sh7722.c um: Add arch/x86/um to MAINTAINERS um: pass siginfo to guest process um: fix ubd_file_size for read-only files md/dm-raid: DM_RAID should select MD_RAID10 md/raid1: submit IO from originating thread instead of md thread. raid5: raid5d handle stripe in batch way raid5: make_request use batch stripe release um: pull interrupt_end() into userspace() um: split syscall_trace(), pass pt_regs to it um: switch UPT_SET_RETURN_VALUE and regs_return_value to pt_regs MIPS: Loongson 2: Sort out clock managment. locks: remove unused lm_release_private ...
Diffstat (limited to 'lib/memweight.c')
-rw-r--r--lib/memweight.c38
1 files changed, 38 insertions, 0 deletions
diff --git a/lib/memweight.c b/lib/memweight.c
new file mode 100644
index 000000000000..e35fc8771893
--- /dev/null
+++ b/lib/memweight.c
@@ -0,0 +1,38 @@
+#include <linux/export.h>
+#include <linux/bug.h>
+#include <linux/bitmap.h>
+
+/**
+ * memweight - count the total number of bits set in memory area
+ * @ptr: pointer to the start of the area
+ * @bytes: the size of the area
+ */
+size_t memweight(const void *ptr, size_t bytes)
+{
+ size_t ret = 0;
+ size_t longs;
+ const unsigned char *bitmap = ptr;
+
+ for (; bytes > 0 && ((unsigned long)bitmap) % sizeof(long);
+ bytes--, bitmap++)
+ ret += hweight8(*bitmap);
+
+ longs = bytes / sizeof(long);
+ if (longs) {
+ BUG_ON(longs >= INT_MAX / BITS_PER_LONG);
+ ret += bitmap_weight((unsigned long *)bitmap,
+ longs * BITS_PER_LONG);
+ bytes -= longs * sizeof(long);
+ bitmap += longs * sizeof(long);
+ }
+ /*
+ * The reason that this last loop is distinct from the preceding
+ * bitmap_weight() call is to compute 1-bits in the last region smaller
+ * than sizeof(long) properly on big-endian systems.
+ */
+ for (; bytes > 0; bytes--, bitmap++)
+ ret += hweight8(*bitmap);
+
+ return ret;
+}
+EXPORT_SYMBOL(memweight);