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Message-ID: <20100224162152.GK3687@quack.suse.cz>
Date: Wed, 24 Feb 2010 17:21:52 +0100
From: Jan Kara <jack@...e.cz>
To: Akinobu Mita <akinobu.mita@...il.com>
Cc: linux-kernel@...r.kernel.org, Jan Kara <jack@...e.cz>
Subject: Re: [PATCH] udf: use ext2_find_next_bit
On Tue 23-02-10 23:11:13, Akinobu Mita wrote:
> Use ext2_find_next_bit (generic_find_next_le_bit) to find the set bit
> in little endian bitmap region.
>
> Signed-off-by: Akinobu Mita <akinobu.mita@...il.com>
> Cc: Jan Kara <jack@...e.cz>
I've looked at the code and I think this is wrong. UDF uses 1 for free
block in the bitmap and 0 for used one. So you need to use
generic_find_next_le_bit...
Something like the patch below?
Honza
--
Jan Kara <jack@...e.cz>
SUSE Labs, CR
---
>From bfc8c674188d4be5856e445f9b57e1b7a3dbff6d Mon Sep 17 00:00:00 2001
From: Jan Kara <jack@...e.cz>
Date: Wed, 24 Feb 2010 17:18:57 +0100
Subject: [PATCH] udf: Use generic function for bit searching
Use generic_find_next_le_bit to search for bits in bitmap so
that we don't duplicate code unnecessarily.
Signed-off-by: Jan Kara <jack@...e.cz>
---
fs/udf/balloc.c | 51 ++-------------------------------------------------
1 files changed, 2 insertions(+), 49 deletions(-)
diff --git a/fs/udf/balloc.c b/fs/udf/balloc.c
index 82372e3..f5ff06c 100644
--- a/fs/udf/balloc.c
+++ b/fs/udf/balloc.c
@@ -31,55 +31,8 @@
#define udf_clear_bit(nr, addr) ext2_clear_bit(nr, addr)
#define udf_set_bit(nr, addr) ext2_set_bit(nr, addr)
#define udf_test_bit(nr, addr) ext2_test_bit(nr, addr)
-#define udf_find_first_one_bit(addr, size) find_first_one_bit(addr, size)
#define udf_find_next_one_bit(addr, size, offset) \
- find_next_one_bit(addr, size, offset)
-
-#define leBPL_to_cpup(x) leNUM_to_cpup(BITS_PER_LONG, x)
-#define leNUM_to_cpup(x, y) xleNUM_to_cpup(x, y)
-#define xleNUM_to_cpup(x, y) (le ## x ## _to_cpup(y))
-#define uintBPL_t uint(BITS_PER_LONG)
-#define uint(x) xuint(x)
-#define xuint(x) __le ## x
-
-static inline int find_next_one_bit(void *addr, int size, int offset)
-{
- uintBPL_t *p = ((uintBPL_t *) addr) + (offset / BITS_PER_LONG);
- int result = offset & ~(BITS_PER_LONG - 1);
- unsigned long tmp;
-
- if (offset >= size)
- return size;
- size -= result;
- offset &= (BITS_PER_LONG - 1);
- if (offset) {
- tmp = leBPL_to_cpup(p++);
- tmp &= ~0UL << offset;
- if (size < BITS_PER_LONG)
- goto found_first;
- if (tmp)
- goto found_middle;
- size -= BITS_PER_LONG;
- result += BITS_PER_LONG;
- }
- while (size & ~(BITS_PER_LONG - 1)) {
- tmp = leBPL_to_cpup(p++);
- if (tmp)
- goto found_middle;
- result += BITS_PER_LONG;
- size -= BITS_PER_LONG;
- }
- if (!size)
- return result;
- tmp = leBPL_to_cpup(p);
-found_first:
- tmp &= ~0UL >> (BITS_PER_LONG - size);
-found_middle:
- return result + ffz(~tmp);
-}
-
-#define find_first_one_bit(addr, size)\
- find_next_one_bit((addr), (size), 0)
+ generic_find_next_le_bit((unsigned long *)addr, size, offset)
static int read_block_bitmap(struct super_block *sb,
struct udf_bitmap *bitmap, unsigned int block,
@@ -356,7 +309,7 @@ repeat:
break;
}
} else {
- bit = udf_find_next_one_bit((char *)bh->b_data,
+ bit = udf_find_next_one_bit(bh->b_data,
sb->s_blocksize << 3,
group_start << 3);
if (bit < sb->s_blocksize << 3)
--
1.6.4.2
--
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