From: David Chinner <dgc@sgi.com>
To: xfs@oss.sgi.com
Cc: xfs-dev@sgi.com
Subject: [PATCH] Clean up bitops
Date: Tue, 30 Oct 2007 10:36:35 +1100 [thread overview]
Message-ID: <20071029233635.GR995458@sgi.com> (raw)
Use the generic bitops rather than implementing them ourselves.
Patch inspired by Andi Kleen.
Signed-off-by: Dave Chinner <dgc@sgi.com>
---
fs/xfs/xfs_bit.c | 103 ---------------------------------------------------
fs/xfs/xfs_bit.h | 27 ++++++++++---
fs/xfs/xfs_rtalloc.c | 19 +++------
3 files changed, 29 insertions(+), 120 deletions(-)
Index: 2.6.x-xfs-new/fs/xfs/xfs_bit.c
===================================================================
--- 2.6.x-xfs-new.orig/fs/xfs/xfs_bit.c 2007-06-20 15:54:59.000000000 +1000
+++ 2.6.x-xfs-new/fs/xfs/xfs_bit.c 2007-10-05 08:48:48.107390247 +1000
@@ -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
Index: 2.6.x-xfs-new/fs/xfs/xfs_bit.h
===================================================================
--- 2.6.x-xfs-new.orig/fs/xfs/xfs_bit.h 2007-06-20 15:54:59.000000000 +1000
+++ 2.6.x-xfs-new/fs/xfs/xfs_bit.h 2007-10-05 09:07:20.574761334 +1000
@@ -47,13 +47,30 @@ static inline __uint64_t xfs_mask64lo(in
}
/* Get high bit set out of 32-bit argument, -1 if none set */
-extern int xfs_highbit32(__uint32_t v);
-
-/* Get low bit set out of 64-bit argument, -1 if none set */
-extern int xfs_lowbit64(__uint64_t v);
+static inline int xfs_highbit32(__uint32_t v)
+{
+ return fls(v) - 1;
+}
/* 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);
Index: 2.6.x-xfs-new/fs/xfs/xfs_rtalloc.c
===================================================================
--- 2.6.x-xfs-new.orig/fs/xfs/xfs_rtalloc.c 2007-08-24 22:24:45.000000000 +1000
+++ 2.6.x-xfs-new/fs/xfs/xfs_rtalloc.c 2007-10-05 09:08:04.365058330 +1000
@@ -73,18 +73,6 @@ STATIC int xfs_rtmodify_summary(xfs_moun
*/
/*
- * 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 @@ xfs_rtallocate_extent_near(
}
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_rtallocate_extent_size(
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 @@ xfs_rtallocate_extent_size(
*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 @@ xfs_growfs_rt(
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 =
next reply other threads:[~2007-10-29 23:36 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-29 23:36 David Chinner [this message]
2007-10-30 10:07 ` [PATCH] Clean up bitops Christoph Hellwig
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