[sheepdog] [PATCH] collie: use bit functions to traverse vdi list

[MORITA Kazutaka]

This increases performance of vdi traversing.

Signed-off-by: MORITA Kazutaka <morita.kazutaka at lab.ntt.co.jp>
---
 collie/cluster.c | 12 ++++++------
 collie/common.c  | 10 ++++++----
 2 files changed, 12 insertions(+), 10 deletions(-)

diff --git a/collie/cluster.c b/collie/cluster.c
index 0c5ac13..715d658 100644
--- a/collie/cluster.c
+++ b/collie/cluster.c
@@ -65,6 +65,11 @@ static int list_store(void)
 	return EXIT_SYSFAIL;
 }
 
+static bool no_vdi(const unsigned long *vdis)
+{
+	return find_next_bit(vdis, SD_NR_VDIS, 0) == SD_NR_VDIS;
+}
+
 #define FORMAT_PRINT				\
 	"    __\n"				\
 	"   ()'`;\n"				\
@@ -80,7 +85,6 @@ static int cluster_format(int argc, char **argv)
 	struct timeval tv;
 	char store_name[STORE_LEN];
 	static DECLARE_BITMAP(vdi_inuse, SD_NR_VDIS);
-	unsigned long nr;
 
 	sd_init_req((struct sd_req *)&hdr, SD_OP_READ_VDIS);
 	hdr.data_length = sizeof(vdi_inuse);
@@ -90,11 +94,7 @@ static int cluster_format(int argc, char **argv)
 	if (ret < 0)
 		return EXIT_SYSFAIL;
 
-	for (nr = 0; nr < SD_NR_VDIS; nr++)
-		if (test_bit(nr, vdi_inuse))
-			break;
-
-	if (nr != SD_NR_VDIS)
+	if (!no_vdi(vdi_inuse))
 		confirm(FORMAT_PRINT);
 
 	gettimeofday(&tv, NULL);
diff --git a/collie/common.c b/collie/common.c
index 0642ee0..ce40822 100644
--- a/collie/common.c
+++ b/collie/common.c
@@ -113,6 +113,11 @@ int sd_write_object(uint64_t oid, uint64_t cow_oid, void *data,
 	return SD_RES_SUCCESS;
 }
 
+#define FOR_EACH_VDI(nr, vdis)					\
+	for (nr = find_next_bit((vdis), SD_NR_VDIS, 0);		\
+	     nr < SD_NR_VDIS;					\
+	     nr = find_next_bit((vdis), SD_NR_VDIS, nr + 1))
+
 int parse_vdi(vdi_parser_func_t func, size_t size, void *data)
 {
 	int ret;
@@ -129,13 +134,10 @@ int parse_vdi(vdi_parser_func_t func, size_t size, void *data)
 	if (ret < 0)
 		goto out;
 
-	for (nr = 0; nr < SD_NR_VDIS; nr++) {
+	FOR_EACH_VDI(nr, vdi_inuse) {
 		uint64_t oid;
 		uint32_t snapid;
 
-		if (!test_bit(nr, vdi_inuse))
-			continue;
-
 		oid = vid_to_vdi_oid(nr);
 
 		memset(&i, 0, sizeof(i));
-- 
1.8.1.3.566.gaa39828