On Mon, 2014-09-22 at 15:41 +0200, David Sterba wrote:
> On Mon, Sep 22, 2014 at 04:58:26PM +0800, Gui Hecheng wrote:
> > So we check page alignment every time before we are going to
> > fetch the next @len and after the former piece of data is decompressed.
> > If the current page that we reach has less than 4 bytes left,
> > then we should fetch the next @len at the start of next page.
>
> Thanks for the fix.
>
> > --- a/cmds-restore.c
> > +++ b/cmds-restore.c
> > @@ -57,6 +57,9 @@ static int dry_run = 0;
> >
> > #define LZO_LEN 4
> > #define PAGE_CACHE_SIZE 4096
> > +#define PAGE_CACHE_MASK (~(PAGE_CACHE_SIZE - 1))
> > +#define PAGE_CACHE_ALIGN(addr) (((addr) + PAGE_CACHE_SIZE - 1) \
> > + & PAGE_CACHE_MASK)
>
> This is not type-safe, the PAGE_CACHE_SIZE should be unsigned long.
>
> > #define lzo1x_worst_compress(x) ((x) + ((x) / 16) + 64 + 3)
> >
> > static int decompress_zlib(char *inbuf, char *outbuf, u64 compress_len,
> > @@ -93,6 +96,28 @@ static inline size_t read_compress_length(unsigned char
> > *buf)
> > return le32_to_cpu(dlen);
> > }
> >
> > +static void align_if_need(size_t *tot_in, size_t *in_len)
> > +{
> > + int tot_in_aligned;
> > + int bytes_left;
> > +
> > + tot_in_aligned = PAGE_CACHE_ALIGN(*tot_in);
>
> size_t -> int, plus other tricks that happen inside the macro
>
> > + bytes_left = tot_in_aligned - *tot_in;
>
> int = int - size_t
>
> > +
> > + if (bytes_left >= LZO_LEN)
> > + return;
> > +
> > + /*
> > + * The LZO_LEN bytes is guaranteed to be
> > + * in one page as a whole, so if a page
> > + * has fewer than LZO_LEN bytes left,
> > + * the LZO_LEN bytes should be fetched
> > + * at the start of the next page
> > + */
>
> Nitpick, the comment can use the whole width of the line
>
> /*
> * The LZO_LEN bytes is guaranteed to be in one page as a whole,
> * so if a page has fewer than LZO_LEN bytes left, the LZO_LEN
> * bytes should be fetched at the start of the next page
> */
>
> > + *in_len += bytes_left;
> > + *tot_in = tot_in_aligned;
> > +}
Thanks David, I will pay more attention to the type-safe issue and
resend.
-Gui
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