linux-kernel - Re: [PATCH v7 0/5] Update LZ4 compressor module

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Date:   Wed, 8 Feb 2017 21:24:25 -0800
From:   Eric Biggers <ebiggers3@...il.com>
To:     Minchan Kim <minchan@...nel.org>
Cc:     Sven Schmidt <4sschmid@...ormatik.uni-hamburg.de>,
        akpm@...ux-foundation.org, bongkyu.kim@....com,
        rsalvaterra@...il.com, sergey.senozhatsky@...il.com,
        gregkh@...uxfoundation.org, linux-kernel@...r.kernel.org,
        herbert@...dor.apana.org.au, davem@...emloft.net,
        linux-crypto@...r.kernel.org, anton@...msg.org, ccross@...roid.com,
        keescook@...omium.org, tony.luck@...el.com
Subject: Re: [PATCH v7 0/5] Update LZ4 compressor module

Also I noticed another bug, this time in LZ4_count():

> #if defined(CONFIG_64BIT)
> #define LZ4_ARCH64 1
> #else
> #define LZ4_ARCH64 0
> #endif
...
> #ifdef LZ4_ARCH64
>        if ((pIn < (pInLimit-3))
>                && (LZ4_read32(pMatch) == LZ4_read32(pIn))) {
>                pIn += 4; pMatch += 4;
>        }
> #endif

Because of how LZ4_ARCH64 is defined, it needs to be '#if LZ4_ARCH64'.

But I also think the way upstream LZ4 does 64-bit detection could have just been
left as-is; it has a function which gets inlined:

	static unsigned LZ4_64bits(void) { return sizeof(void*)==8; }

Eric