[XFS] clean up xfs_start_flags

xfs_start_flags can make use of is_power_of_2 to tidy up the test a little
bit.

SGI-PV: 968563
SGI-Modid: xfs-linux-melb:xfs-kern:29327a

Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Tim Shimmin <tes@sgi.com>

fs/xfs/xfs_log_priv.h

@@ -35,11 +35,11 @@ struct xfs_mount;
 #define XLOG_VERSION_1		1
 #define XLOG_VERSION_2		2		/* Large IClogs, Log sunit */
 #define XLOG_VERSION_OKBITS	(XLOG_VERSION_1 | XLOG_VERSION_2)
-#define XLOG_RECORD_BSIZE	(16*1024)	/* eventually 32k */
+#define XLOG_MIN_RECORD_BSIZE	(16*1024)	/* eventually 32k */
 #define XLOG_BIG_RECORD_BSIZE	(32*1024)	/* 32k buffers */
 #define XLOG_MAX_RECORD_BSIZE	(256*1024)
 #define XLOG_HEADER_CYCLE_SIZE	(32*1024)	/* cycle data in header */
-#define XLOG_RECORD_BSHIFT	14		/* 16384 == 1 << 14 */
+#define XLOG_MIN_RECORD_BSHIFT	14		/* 16384 == 1 << 14 */
 #define XLOG_BIG_RECORD_BSHIFT	15		/* 32k == 1 << 15 */
 #define XLOG_MAX_RECORD_BSHIFT	18		/* 256k == 1 << 18 */
 #define XLOG_BTOLSUNIT(log, b)  (((b)+(log)->l_mp->m_sb.sb_logsunit-1) / \

fs/xfs/xfs_vfsops.c

@@ -238,11 +238,9 @@ xfs_start_flags(
 	mp->m_logbufs = ap->logbufs;
 	if (ap->logbufsize != -1 &&
 	    ap->logbufsize !=  0 &&
-	    ap->logbufsize != 16 * 1024 &&
-	    ap->logbufsize != 32 * 1024 &&
-	    ap->logbufsize != 64 * 1024 &&
-	    ap->logbufsize != 128 * 1024 &&
-	    ap->logbufsize != 256 * 1024) {
+	    (ap->logbufsize < XLOG_MIN_RECORD_BSIZE ||
+	     ap->logbufsize > XLOG_MAX_RECORD_BSIZE ||
+	     !is_power_of_2(ap->logbufsize))) {
 		cmn_err(CE_WARN,
 	"XFS: invalid logbufsize: %d [not 16k,32k,64k,128k or 256k]",
 			ap->logbufsize);