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SubjectRe: [PATCH] Fix ext4 bitops
On Fri, Feb 01, 2008 at 10:04:04PM +0100, Bastian Blank wrote:
> On Fri, Feb 01, 2008 at 12:22:57PM -0800, Andrew Morton wrote:
> > On Fri, 1 Feb 2008 21:02:08 +0100
> > Bastian Blank <bastian@waldi.eu.org> wrote:
> >
> > > Fix ext4 bitops.
> >
> > This is incomplete. Please tell us what was "fixed".
> >
> > If it was a build error then please quote the compile error output in the
> > changelog, as well as the usual description of what the problem is, and how
> > it was fixed.
>
> | fs/ext4/mballoc.c: In function 'ext4_mb_generate_buddy':
> | fs/ext4/mballoc.c:954: error: implicit declaration of function 'generic_find_next_le_bit'
>
> The s390 specific bitops uses parts of the generic implementation.
> Include the correct header.

That doesn't work:

fs/built-in.o: In function `ext4_mb_release_inode_pa':
mballoc.c:(.text+0x95a8a): undefined reference to `generic_find_next_le_bit'
fs/built-in.o: In function `ext4_mb_init_cache':
mballoc.c:(.text+0x967ea): undefined reference to `generic_find_next_le_bit'

This still needs generic_find_next_le_bit which comes
from lib/find_next_bit.c. That one doesn't get built on s390 since we
don't set GENERIC_FIND_NEXT_BIT.
Currently we have the lengthly patch below queued.

Subject: [PATCH] Implement ext2_find_next_bit.

From: Heiko Carstens <heiko.carstens@de.ibm.com>

Fixes this compile error:

fs/ext4/mballoc.c:
In function 'ext4_mb_generate_buddy':
fs/ext4/mballoc.c:954:
error: implicit declaration of function 'generic_find_next_le_bit'

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---

include/asm-s390/bitops.h | 130 +++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 128 insertions(+), 2 deletions(-)

diff -urpN linux-2.6/include/asm-s390/bitops.h linux-2.6-patched/include/asm-s390/bitops.h
--- linux-2.6/include/asm-s390/bitops.h 2008-02-01 12:29:03.000000000 +0100
+++ linux-2.6-patched/include/asm-s390/bitops.h 2008-02-01 12:31:39.000000000 +0100
@@ -772,8 +772,6 @@ static inline int sched_find_first_bit(u
test_and_clear_bit((nr)^(__BITOPS_WORDSIZE - 8), (unsigned long *)addr)
#define ext2_test_bit(nr, addr) \
test_bit((nr)^(__BITOPS_WORDSIZE - 8), (unsigned long *)addr)
-#define ext2_find_next_bit(addr, size, off) \
- generic_find_next_le_bit((unsigned long *)(addr), (size), (off))

#ifndef __s390x__

@@ -820,6 +818,48 @@ ext2_find_first_zero_bit(void *vaddr, un
return (res < size) ? res : size;
}

+static inline int __ext2_find_first_bit(void *vaddr, unsigned int size)
+{
+ typedef struct { long _[__BITOPS_WORDS(size)]; } addrtype;
+ unsigned long cmp, count;
+ unsigned int res;
+
+ if (!size)
+ return 0;
+ asm volatile(
+ " lhi %1,0\n"
+ " lr %2,%3\n"
+ " lhi %0,0\n"
+ " ahi %2,31\n"
+ " srl %2,5\n"
+ "0: cl %1,0(%0,%4)\n"
+ " jne 1f\n"
+ " ahi %0,4\n"
+ " brct %2,0b\n"
+ " lr %0,%3\n"
+ " j 4f\n"
+ "1: l %2,0(%0,%4)\n"
+ " sll %0,3\n"
+ " ahi %0,24\n"
+ " lhi %1,0xff\n"
+ " tmh %2,0xffff\n"
+ " jnz 2f\n"
+ " ahi %0,-16\n"
+ " srl %2,16\n"
+ "2: tml %2,0xff00\n"
+ " jnz 3f\n"
+ " ahi %0,-8\n"
+ " srl %2,8\n"
+ "3: nr %2,%1\n"
+ " ic %2,0(%2,%5)\n"
+ " alr %0,%2\n"
+ "4:"
+ : "=&a" (res), "=&d" (cmp), "=&a" (count)
+ : "a" (size), "a" (vaddr), "a" (&_sb_findmap),
+ "m" (*(addrtype *) vaddr) : "cc");
+ return (res < size) ? res : size;
+}
+
#else /* __s390x__ */

static inline unsigned long
@@ -867,6 +907,51 @@ ext2_find_first_zero_bit(void *vaddr, un
return (res < size) ? res : size;
}

+static inline unsigned long __ext2_find_first_bit(void *vaddr,
+ unsigned long size)
+{
+ typedef struct { long _[__BITOPS_WORDS(size)]; } addrtype;
+ unsigned long res, cmp, count;
+
+ if (!size)
+ return 0;
+ asm volatile(
+ " lghi %1,0\n"
+ " lgr %2,%3\n"
+ " lghi %0,0\n"
+ " aghi %2,63\n"
+ " srlg %2,%2,6\n"
+ "0: clg %1,0(%0,%4)\n"
+ " jne 1f\n"
+ " aghi %0,8\n"
+ " brct %2,0b\n"
+ " lgr %0,%3\n"
+ " j 5f\n"
+ "1: cl %1,0(%0,%4)\n"
+ " jne 2f\n"
+ " aghi %0,4\n"
+ "2: l %2,0(%0,%4)\n"
+ " sllg %0,%0,3\n"
+ " aghi %0,24\n"
+ " lghi %1,0xff\n"
+ " tmlh %2,0xffff\n"
+ " jnz 3f\n"
+ " aghi %0,-16\n"
+ " srl %2,16\n"
+ "3: tmll %2,0xff00\n"
+ " jnz 4f\n"
+ " aghi %0,-8\n"
+ " srl %2,8\n"
+ "4: ngr %2,%1\n"
+ " ic %2,0(%2,%5)\n"
+ " algr %0,%2\n"
+ "5:"
+ : "=&a" (res), "=&d" (cmp), "=&a" (count)
+ : "a" (size), "a" (vaddr), "a" (&_sb_findmap),
+ "m" (*(addrtype *) vaddr) : "cc");
+ return (res < size) ? res : size;
+}
+
#endif /* __s390x__ */

static inline int
@@ -910,6 +995,47 @@ ext2_find_next_zero_bit(void *vaddr, uns
return offset + ext2_find_first_zero_bit(p, size);
}

+static inline unsigned long ext2_find_next_bit(void *vaddr, unsigned long size,
+ unsigned long offset)
+{
+ unsigned long *addr = vaddr, *p;
+ unsigned long word, bit, set;
+
+ if (offset >= size)
+ return size;
+ bit = offset & (__BITOPS_WORDSIZE - 1);
+ offset -= bit;
+ size -= offset;
+ p = addr + offset / __BITOPS_WORDSIZE;
+ if (bit) {
+#ifndef __s390x__
+ asm volatile(
+ " ic %0,0(%1)\n"
+ " icm %0,2,1(%1)\n"
+ " icm %0,4,2(%1)\n"
+ " icm %0,8,3(%1)"
+ : "=&a" (word) : "a" (p), "m" (*p) : "cc");
+#else
+ asm volatile(
+ " lrvg %0,%1"
+ : "=a" (word) : "m" (*p) );
+#endif
+ /*
+ * s390 version of __ffs returns __BITOPS_WORDSIZE
+ * if no one bit is present in the word.
+ */
+ set = __ffs(word >> bit) + bit;
+ if (set >= size)
+ return size + offset;
+ if (set < __BITOPS_WORDSIZE)
+ return set + offset;
+ offset += __BITOPS_WORDSIZE;
+ size -= __BITOPS_WORDSIZE;
+ p++;
+ }
+ return offset + __ext2_find_first_bit(p, size);
+}
+
#include <asm-generic/bitops/minix.h>

#endif /* __KERNEL__ */

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