[XFS] Use the generic bitops rather than implementing them ourselves.

Patch inspired by Andi Kleen. SGI-PV: 971186 SGI-Modid: xfs-linux-melb:xfs-kern:30000a Signed-off-by: David Chinner <dgc@sgi.com> Signed-off-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>

[XFS] Use the generic bitops rather than implementing them ourselves.
Patch inspired by Andi Kleen. SGI-PV: 971186 SGI-Modid: xfs-linux-melb:xfs-kern:30000a Signed-off-by: David Chinner <dgc@sgi.com> Signed-off-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
David Chinner · Lachlan McIlroy
1 parent c319b58b13
Showing 3 changed files with 29 additions and 120 deletions Side-by-side Diff
fs/xfs/xfs_bit.c
fs/xfs/xfs_bit.h
fs/xfs/xfs_rtalloc.c
@@ -25,109 +25,6 @@
  * XFS bit manipulation routines, used in non-realtime code.
  */
  
-#ifndef HAVE_ARCH_HIGHBIT
-/*
- * Index of high bit number in byte, -1 for none set, 0..7 otherwise.
- */
-static const char xfs_highbit[256] = {
-       -1, 0, 1, 1, 2, 2, 2, 2,			/* 00 .. 07 */
-	3, 3, 3, 3, 3, 3, 3, 3,			/* 08 .. 0f */
-	4, 4, 4, 4, 4, 4, 4, 4,			/* 10 .. 17 */
-	4, 4, 4, 4, 4, 4, 4, 4,			/* 18 .. 1f */
-	5, 5, 5, 5, 5, 5, 5, 5,			/* 20 .. 27 */
-	5, 5, 5, 5, 5, 5, 5, 5,			/* 28 .. 2f */
-	5, 5, 5, 5, 5, 5, 5, 5,			/* 30 .. 37 */
-	5, 5, 5, 5, 5, 5, 5, 5,			/* 38 .. 3f */
-	6, 6, 6, 6, 6, 6, 6, 6,			/* 40 .. 47 */
-	6, 6, 6, 6, 6, 6, 6, 6,			/* 48 .. 4f */
-	6, 6, 6, 6, 6, 6, 6, 6,			/* 50 .. 57 */
-	6, 6, 6, 6, 6, 6, 6, 6,			/* 58 .. 5f */
-	6, 6, 6, 6, 6, 6, 6, 6,			/* 60 .. 67 */
-	6, 6, 6, 6, 6, 6, 6, 6,			/* 68 .. 6f */
-	6, 6, 6, 6, 6, 6, 6, 6,			/* 70 .. 77 */
-	6, 6, 6, 6, 6, 6, 6, 6,			/* 78 .. 7f */
-	7, 7, 7, 7, 7, 7, 7, 7,			/* 80 .. 87 */
-	7, 7, 7, 7, 7, 7, 7, 7,			/* 88 .. 8f */
-	7, 7, 7, 7, 7, 7, 7, 7,			/* 90 .. 97 */
-	7, 7, 7, 7, 7, 7, 7, 7,			/* 98 .. 9f */
-	7, 7, 7, 7, 7, 7, 7, 7,			/* a0 .. a7 */
-	7, 7, 7, 7, 7, 7, 7, 7,			/* a8 .. af */
-	7, 7, 7, 7, 7, 7, 7, 7,			/* b0 .. b7 */
-	7, 7, 7, 7, 7, 7, 7, 7,			/* b8 .. bf */
-	7, 7, 7, 7, 7, 7, 7, 7,			/* c0 .. c7 */
-	7, 7, 7, 7, 7, 7, 7, 7,			/* c8 .. cf */
-	7, 7, 7, 7, 7, 7, 7, 7,			/* d0 .. d7 */
-	7, 7, 7, 7, 7, 7, 7, 7,			/* d8 .. df */
-	7, 7, 7, 7, 7, 7, 7, 7,			/* e0 .. e7 */
-	7, 7, 7, 7, 7, 7, 7, 7,			/* e8 .. ef */
-	7, 7, 7, 7, 7, 7, 7, 7,			/* f0 .. f7 */
-	7, 7, 7, 7, 7, 7, 7, 7,			/* f8 .. ff */
-};
-#endif
-
-/*
- * xfs_highbit32: get high bit set out of 32-bit argument, -1 if none set.
- */
-inline int
-xfs_highbit32(
-	__uint32_t	v)
-{
-#ifdef HAVE_ARCH_HIGHBIT
-	return highbit32(v);
-#else
-	int		i;
-
-	if (v & 0xffff0000)
-		if (v & 0xff000000)
-			i = 24;
-		else
-			i = 16;
-	else if (v & 0x0000ffff)
-		if (v & 0x0000ff00)
-			i = 8;
-		else
-			i = 0;
-	else
-		return -1;
-	return i + xfs_highbit[(v >> i) & 0xff];
-#endif
-}
-
-/*
- * xfs_lowbit64: get low bit set out of 64-bit argument, -1 if none set.
- */
-int
-xfs_lowbit64(
-	__uint64_t	v)
-{
-	__uint32_t	w = (__uint32_t)v;
-	int		n = 0;
-
-	if (w) {	/* lower bits */
-		n = ffs(w);
-	} else {	/* upper bits */
-		w = (__uint32_t)(v >> 32);
-		if (w && (n = ffs(w)))
-			n += 32;
-	}
-	return n - 1;
-}
-
-/*
- * xfs_highbit64: get high bit set out of 64-bit argument, -1 if none set.
- */
-int
-xfs_highbit64(
-	__uint64_t	v)
-{
-	__uint32_t	h = (__uint32_t)(v >> 32);
-
-	if (h)
-		return xfs_highbit32(h) + 32;
-	return xfs_highbit32((__uint32_t)v);
-}
-
-
 /*
  * Return whether bitmap is empty.
  * Size is number of words in the bitmap, which is padded to word boundary
@@ -47,13 +47,30 @@
 }
  
 /* Get high bit set out of 32-bit argument, -1 if none set */
-extern int xfs_highbit32(__uint32_t v);
+static inline int xfs_highbit32(__uint32_t v)
+{
+	return fls(v) - 1;
+}
  
-/* Get low bit set out of 64-bit argument, -1 if none set */
-extern int xfs_lowbit64(__uint64_t v);
-
 /* Get high bit set out of 64-bit argument, -1 if none set */
-extern int xfs_highbit64(__uint64_t);
+static inline int xfs_highbit64(__uint64_t v)
+{
+	return fls64(v) - 1;
+}
+
+/* Get low bit set out of 32-bit argument, -1 if none set */
+static inline int xfs_lowbit32(__uint32_t v)
+{
+	unsigned long	t = v;
+	return (v) ? find_first_bit(&t, 32) : -1;
+}
+
+/* Get low bit set out of 64-bit argument, -1 if none set */
+static inline int xfs_lowbit64(__uint64_t v)
+{
+	unsigned long	t = v;
+	return (v) ? find_first_bit(&t, 64) : -1;
+}
  
 /* Return whether bitmap is empty (1 == empty) */
 extern int xfs_bitmap_empty(uint *map, uint size);
@@ -73,18 +73,6 @@
  */
  
 /*
- * xfs_lowbit32: get low bit set out of 32-bit argument, -1 if none set.
- */
-STATIC int
-xfs_lowbit32(
-	__uint32_t	v)
-{
-	if (v)
-		return ffs(v) - 1;
-	return -1;
-}
-
-/*
  * Allocate space to the bitmap or summary file, and zero it, for growfs.
  */
 STATIC int				/* error */
@@ -444,6 +432,7 @@
 	}
 	bbno = XFS_BITTOBLOCK(mp, bno);
 	i = 0;
+	ASSERT(minlen != 0);
 	log2len = xfs_highbit32(minlen);
 	/*
 	 * Loop over all bitmap blocks (bbno + i is current block).
@@ -612,6 +601,8 @@
 	xfs_suminfo_t	sum;		/* summary information for extents */
  
 	ASSERT(minlen % prod == 0 && maxlen % prod == 0);
+	ASSERT(maxlen != 0);
+
 	/*
 	 * Loop over all the levels starting with maxlen.
 	 * At each level, look at all the bitmap blocks, to see if there
@@ -669,6 +660,9 @@
 		*rtblock = NULLRTBLOCK;
 		return 0;
 	}
+	ASSERT(minlen != 0);
+	ASSERT(maxlen != 0);
+
 	/*
 	 * Loop over sizes, from maxlen down to minlen.
 	 * This time, when we do the allocations, allow smaller ones
@@ -1954,6 +1948,7 @@
 				  nsbp->sb_blocksize * nsbp->sb_rextsize);
 		nsbp->sb_rextents = nsbp->sb_rblocks;
 		do_div(nsbp->sb_rextents, nsbp->sb_rextsize);
+		ASSERT(nsbp->sb_rextents != 0);
 		nsbp->sb_rextslog = xfs_highbit32(nsbp->sb_rextents);
 		nrsumlevels = nmp->m_rsumlevels = nsbp->sb_rextslog + 1;
 		nrsumsize =
...	...	@@ -25,109 +25,6 @@
25	25	* XFS bit manipulation routines, used in non-realtime code.
26	26	*/
27	27
28		-#ifndef HAVE_ARCH_HIGHBIT
29		-/*
30		- * Index of high bit number in byte, -1 for none set, 0..7 otherwise.
31		- */
32		-static const char xfs_highbit[256] = {
33		- -1, 0, 1, 1, 2, 2, 2, 2, /* 00 .. 07 */
34		- 3, 3, 3, 3, 3, 3, 3, 3, /* 08 .. 0f */
35		- 4, 4, 4, 4, 4, 4, 4, 4, /* 10 .. 17 */
36		- 4, 4, 4, 4, 4, 4, 4, 4, /* 18 .. 1f */
37		- 5, 5, 5, 5, 5, 5, 5, 5, /* 20 .. 27 */
38		- 5, 5, 5, 5, 5, 5, 5, 5, /* 28 .. 2f */
39		- 5, 5, 5, 5, 5, 5, 5, 5, /* 30 .. 37 */
40		- 5, 5, 5, 5, 5, 5, 5, 5, /* 38 .. 3f */
41		- 6, 6, 6, 6, 6, 6, 6, 6, /* 40 .. 47 */
42		- 6, 6, 6, 6, 6, 6, 6, 6, /* 48 .. 4f */
43		- 6, 6, 6, 6, 6, 6, 6, 6, /* 50 .. 57 */
44		- 6, 6, 6, 6, 6, 6, 6, 6, /* 58 .. 5f */
45		- 6, 6, 6, 6, 6, 6, 6, 6, /* 60 .. 67 */
46		- 6, 6, 6, 6, 6, 6, 6, 6, /* 68 .. 6f */
47		- 6, 6, 6, 6, 6, 6, 6, 6, /* 70 .. 77 */
48		- 6, 6, 6, 6, 6, 6, 6, 6, /* 78 .. 7f */
49		- 7, 7, 7, 7, 7, 7, 7, 7, /* 80 .. 87 */
50		- 7, 7, 7, 7, 7, 7, 7, 7, /* 88 .. 8f */
51		- 7, 7, 7, 7, 7, 7, 7, 7, /* 90 .. 97 */
52		- 7, 7, 7, 7, 7, 7, 7, 7, /* 98 .. 9f */
53		- 7, 7, 7, 7, 7, 7, 7, 7, /* a0 .. a7 */
54		- 7, 7, 7, 7, 7, 7, 7, 7, /* a8 .. af */
55		- 7, 7, 7, 7, 7, 7, 7, 7, /* b0 .. b7 */
56		- 7, 7, 7, 7, 7, 7, 7, 7, /* b8 .. bf */
57		- 7, 7, 7, 7, 7, 7, 7, 7, /* c0 .. c7 */
58		- 7, 7, 7, 7, 7, 7, 7, 7, /* c8 .. cf */
59		- 7, 7, 7, 7, 7, 7, 7, 7, /* d0 .. d7 */
60		- 7, 7, 7, 7, 7, 7, 7, 7, /* d8 .. df */
61		- 7, 7, 7, 7, 7, 7, 7, 7, /* e0 .. e7 */
62		- 7, 7, 7, 7, 7, 7, 7, 7, /* e8 .. ef */
63		- 7, 7, 7, 7, 7, 7, 7, 7, /* f0 .. f7 */
64		- 7, 7, 7, 7, 7, 7, 7, 7, /* f8 .. ff */
65		-};
66		-#endif
67		-
68		-/*
69		- * xfs_highbit32: get high bit set out of 32-bit argument, -1 if none set.
70		- */
71		-inline int
72		-xfs_highbit32(
73		- __uint32_t v)
74		-{
75		-#ifdef HAVE_ARCH_HIGHBIT
76		- return highbit32(v);
77		-#else
78		- int i;
79		-
80		- if (v & 0xffff0000)
81		- if (v & 0xff000000)
82		- i = 24;
83		- else
84		- i = 16;
85		- else if (v & 0x0000ffff)
86		- if (v & 0x0000ff00)
87		- i = 8;
88		- else
89		- i = 0;
90		- else
91		- return -1;
92		- return i + xfs_highbit[(v >> i) & 0xff];
93		-#endif
94		-}
95		-
96		-/*
97		- * xfs_lowbit64: get low bit set out of 64-bit argument, -1 if none set.
98		- */
99		-int
100		-xfs_lowbit64(
101		- __uint64_t v)
102		-{
103		- __uint32_t w = (__uint32_t)v;
104		- int n = 0;
105		-
106		- if (w) { /* lower bits */
107		- n = ffs(w);
108		- } else { /* upper bits */
109		- w = (__uint32_t)(v >> 32);
110		- if (w && (n = ffs(w)))
111		- n += 32;
112		- }
113		- return n - 1;
114		-}
115		-
116		-/*
117		- * xfs_highbit64: get high bit set out of 64-bit argument, -1 if none set.
118		- */
119		-int
120		-xfs_highbit64(
121		- __uint64_t v)
122		-{
123		- __uint32_t h = (__uint32_t)(v >> 32);
124		-
125		- if (h)
126		- return xfs_highbit32(h) + 32;
127		- return xfs_highbit32((__uint32_t)v);
128		-}
129		-
130		-
131	28	/*
132	29	* Return whether bitmap is empty.
133	30	* Size is number of words in the bitmap, which is padded to word boundary
...	...	@@ -47,13 +47,30 @@
47	47	}
48	48
49	49	/* Get high bit set out of 32-bit argument, -1 if none set */
50		-extern int xfs_highbit32(__uint32_t v);
	50	+static inline int xfs_highbit32(__uint32_t v)
	51	+{
	52	+ return fls(v) - 1;
	53	+}
51	54
52		-/* Get low bit set out of 64-bit argument, -1 if none set */
53		-extern int xfs_lowbit64(__uint64_t v);
54		-
55	55	/* Get high bit set out of 64-bit argument, -1 if none set */
56		-extern int xfs_highbit64(__uint64_t);
	56	+static inline int xfs_highbit64(__uint64_t v)
	57	+{
	58	+ return fls64(v) - 1;
	59	+}
	60	+
	61	+/* Get low bit set out of 32-bit argument, -1 if none set */
	62	+static inline int xfs_lowbit32(__uint32_t v)
	63	+{
	64	+ unsigned long t = v;
	65	+ return (v) ? find_first_bit(&t, 32) : -1;
	66	+}
	67	+
	68	+/* Get low bit set out of 64-bit argument, -1 if none set */
	69	+static inline int xfs_lowbit64(__uint64_t v)
	70	+{
	71	+ unsigned long t = v;
	72	+ return (v) ? find_first_bit(&t, 64) : -1;
	73	+}
57	74
58	75	/* Return whether bitmap is empty (1 == empty) */
59	76	extern int xfs_bitmap_empty(uint *map, uint size);
...	...	@@ -73,18 +73,6 @@
73	73	*/
74	74
75	75	/*
76		- * xfs_lowbit32: get low bit set out of 32-bit argument, -1 if none set.
77		- */
78		-STATIC int
79		-xfs_lowbit32(
80		- __uint32_t v)
81		-{
82		- if (v)
83		- return ffs(v) - 1;
84		- return -1;
85		-}
86		-
87		-/*
88	76	* Allocate space to the bitmap or summary file, and zero it, for growfs.
89	77	*/
90	78	STATIC int /* error */
...	...	@@ -444,6 +432,7 @@
444	432	}
445	433	bbno = XFS_BITTOBLOCK(mp, bno);
446	434	i = 0;
	435	+ ASSERT(minlen != 0);
447	436	log2len = xfs_highbit32(minlen);
448	437	/*
449	438	* Loop over all bitmap blocks (bbno + i is current block).
...	...	@@ -612,6 +601,8 @@
612	601	xfs_suminfo_t sum; /* summary information for extents */
613	602
614	603	ASSERT(minlen % prod == 0 && maxlen % prod == 0);
	604	+ ASSERT(maxlen != 0);
	605	+
615	606	/*
616	607	* Loop over all the levels starting with maxlen.
617	608	* At each level, look at all the bitmap blocks, to see if there
...	...	@@ -669,6 +660,9 @@
669	660	*rtblock = NULLRTBLOCK;
670	661	return 0;
671	662	}
	663	+ ASSERT(minlen != 0);
	664	+ ASSERT(maxlen != 0);
	665	+
672	666	/*
673	667	* Loop over sizes, from maxlen down to minlen.
674	668	* This time, when we do the allocations, allow smaller ones
...	...	@@ -1954,6 +1948,7 @@
1954	1948	nsbp->sb_blocksize * nsbp->sb_rextsize);
1955	1949	nsbp->sb_rextents = nsbp->sb_rblocks;
1956	1950	do_div(nsbp->sb_rextents, nsbp->sb_rextsize);
	1951	+ ASSERT(nsbp->sb_rextents != 0);
1957	1952	nsbp->sb_rextslog = xfs_highbit32(nsbp->sb_rextents);
1958	1953	nrsumlevels = nmp->m_rsumlevels = nsbp->sb_rextslog + 1;
1959	1954	nrsumsize =