On Thu, Dec 2, 2010 at 1:49 PM, Ryan Mallon <ryan@xxxxxxxxxxxxxxxx> wrote:
> On 12/01/2010 10:57 AM, Charles Manning wrote:
>> Signed-off-by: Charles Manning <cdhmanning@xxxxxxxxx>
>> ---
>> fs/yaffs2/yaffs_allocator.c | 397 +++++++++++++++++++++++++++++++++++++++++++
>> fs/yaffs2/yaffs_allocator.h | 30 ++++
>> fs/yaffs2/yaffs_attribs.c | 124 ++++++++++++++
>> fs/yaffs2/yaffs_attribs.h | 28 +++
>> fs/yaffs2/yaffs_bitmap.c | 104 +++++++++++
>> fs/yaffs2/yaffs_bitmap.h | 33 ++++
>> 6 files changed, 716 insertions(+), 0 deletions(-)
>> create mode 100644 fs/yaffs2/yaffs_allocator.c
>> create mode 100644 fs/yaffs2/yaffs_allocator.h
>> create mode 100644 fs/yaffs2/yaffs_attribs.c
>> create mode 100644 fs/yaffs2/yaffs_attribs.h
>> create mode 100644 fs/yaffs2/yaffs_bitmap.c
>> create mode 100644 fs/yaffs2/yaffs_bitmap.h
>>
>> diff --git a/fs/yaffs2/yaffs_allocator.c b/fs/yaffs2/yaffs_allocator.c
>> new file mode 100644
>> index 0000000..b9fe31e
>> --- /dev/null
>> +++ b/fs/yaffs2/yaffs_allocator.c
>> @@ -0,0 +1,397 @@
>> +/*
>> + * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
>> + *
>> + * Copyright (C) 2002-2010 Aleph One Ltd.
>> + * for Toby Churchill Ltd and Brightstar Engineering
>> + *
>> + * Created by Charles Manning <charles@xxxxxxxxxxxx>
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 as
>> + * published by the Free Software Foundation.
>> + */
>> +
>> +#include "yaffs_allocator.h"
>> +#include "yaffs_guts.h"
>> +#include "yaffs_trace.h"
>> +#include "yportenv.h"
>> +
>> +#ifdef CONFIG_YAFFS_YMALLOC_ALLOCATOR
>
> This doesn't appear to be defined anywhere and is not in Kconfig. Is
> this just a wrapper for support on other operating systems or does it
> can it be used on Linux for debugging? In the former case it should
> probably removed and in the latter it should probably have a comment
> explaining why you would want to define it.
>
> <snip>
>
>> +
>> +#include "yaffs_bitmap.h"
>> +#include "yaffs_trace.h"
>> +/*
>> + * Chunk bitmap manipulations
>> + */
>> +
>> +static Y_INLINE u8 *yaffs_block_bits(struct yaffs_dev *dev, int blk)
>
> Should just use inline.
>
> <snip>
>
>> +
>> +int yaffs_still_some_chunks(struct yaffs_dev *dev, int blk)
>> +{
>> + u8 *blk_bits = yaffs_block_bits(dev, blk);
>> + int i;
>> + for (i = 0; i < dev->chunk_bit_stride; i++) {
>
> Nitpick: You should have a blank line between variable declarations and
> start of code.
>
> <snip>
>
>> +int yaffs_count_chunk_bits(struct yaffs_dev *dev, int blk)
>> +{
>> + u8 *blk_bits = yaffs_block_bits(dev, blk);
>> + int i;
>> + int n = 0;
>> + for (i = 0; i < dev->chunk_bit_stride; i++) {
>> + u8 x = *blk_bits;
>> + while (x) {
>> + if (x & 1)
>> + n++;
>> + x >>= 1;
>> + }
>> +
>> + blk_bits++;
>> + }
>> + return n;
>> +}
>
>
> This is possibly more concise as a for loop. Also moving the definitions
> all to the top of the file and combining same types definitions on one
> line reduces this function to:
>
> int yaffs_count_chunk_bits(struct yaffs_dev *dev, int blk)
> {
> u8 x, *blk_bits = yaffs_block_bits(dev, blk);
> int i, n = 0;
>
> for (i = 0; i < dev->chunk_bit_stride; i++, blk_bits++)
> for (x = *blk_bits; x; x >>= 1)
> if (x & 1)
> n++;
>
> return n;
> }
Actually, how about using the standard hamming weight function?
This adds a dependency on linux/bitops.h, but seems to be carefully
crafted to be as fast as possible based on the available hardware.
int yaffs_count_chunk_bits(struct yaffs_dev *dev, int blk)
{
u8 *blk_bits = yaffs_block_bits(dev, blk);
int i, n = 0;
for (i = 0; i < dev->chunk_bit_stride; i++, blk_bits++)
n += hweight8(*blk_bits);
return n;
}
Kevin Granade
>
> ~Ryan
>
> --
> Bluewater Systems Ltd - ARM Technology Solution Centre
>
> Ryan Mallon 5 Amuri Park, 404 Barbadoes St
> ryan@xxxxxxxxxxxxxxxx PO Box 13 889, Christchurch 8013
> http://www.bluewatersys.com New Zealand
> Phone: +64 3 3779127 Freecall: Australia 1800 148 751
> Fax: +64 3 3779135 USA 1800 261 2934
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