Re: [PATCH 0/4] variables fixes in compression.c

[David Sterba <dsterba@suse.cz>]

On Sat, May 29, 2021 at 05:48:32PM +0800, Anand Jain wrote:
> Patch (btrfs: reduce compressed_bio member's types) reduced the
> size to unsigned int as in [1]. Fix its cascading effects here.
> And one stale comment in the patch 4/4.
> 
> [1]
> -       unsigned long len;
> +       unsigned int len;
> 
> -       int compress_type;
> +       u8 compress_type;
> 
> -       unsigned long nr_pages;
> +       unsigned int nr_pages;
> 
> -       unsigned long compressed_len;
> +       unsigned int compressed_len;
> 
> -       int errors;
> +       u8 errors;
> 
> As shown in [2], we set the max compressable block size to 128K. So
> struct async_extent can reduce some of its members to unsigned int as
> well.
> 
> [2]
> static noinline int compress_file_range(struct async_chunk *async_chunk)
> ::
>   617         total_compressed = min_t(unsigned long, total_compressed,
>   618                         BTRFS_MAX_UNCOMPRESSED);
> 
> But changes touches too many places, and my first attempt to fix
> is unsatisfactory to me, so I am just sending the changes limited to the
> file compression.c.

That's fin. As long as a patch does one change (possibly cascading to
more places) it should be doable step by step.

> Anand Jain (4):
>   btrfs: optimize users of members of the struct compressed_bio
>   btrfs: optimize variables size in btrfs_submit_compressed_read
>   btrfs: optimize variables size in btrfs_submit_compressed_write
>   btrfs: fix comment about max_out in btrfs_compress_pages

Added to misc-next, thanks.