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Date:   Fri, 6 Nov 2020 18:38:46 +0000
From:   Christoph Hellwig <hch@infradead.org>
To:     Nick Terrell <nickrterrell@gmail.com>
Cc:     Herbert Xu <herbert@gondor.apana.org.au>,
        linux-crypto@vger.kernel.org, linux-btrfs@vger.kernel.org,
        squashfs-devel@lists.sourceforge.net,
        linux-f2fs-devel@lists.sourceforge.net,
        linux-kernel@vger.kernel.org, Kernel Team <Kernel-team@fb.com>,
        Nick Terrell <terrelln@fb.com>, Chris Mason <clm@fb.com>,
        Petr Malat <oss@malat.biz>, Johannes Weiner <jweiner@fb.com>,
        Niket Agarwal <niketa@fb.com>, Yann Collet <cyan@fb.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [PATCH v5 1/9] lib: zstd: Add zstd compatibility wrapper
Message-ID: <20201106183846.GA28005@infradead.org>
References: <20201103060535.8460-1-nickrterrell@gmail.com>
 <20201103060535.8460-2-nickrterrell@gmail.com>
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In-Reply-To: <20201103060535.8460-2-nickrterrell@gmail.com>
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You just keep resedning this crap, don't you?  Haven't you been told
multiple times to provide a proper kernel API by now?

On Mon, Nov 02, 2020 at 10:05:27PM -0800, Nick Terrell wrote:
> From: Nick Terrell <terrelln@fb.com>
> 
> Adds zstd_compat.h which provides the necessary functions from the
> current zstd.h API. It is only active for zstd versions 1.4.6 and newer.
> That means it is disabled currently, but will become active when a later
> patch in this series updates the zstd library in the kernel to 1.4.6.
> 
> This header allows the zstd upgrade to 1.4.6 without changing any
> callers, since they all include zstd through the compatibility wrapper.
> Later patches in this series transition each caller away from the
> compatibility wrapper. After all the callers have been transitioned away
> from the compatibility wrapper, the final patch in this series deletes
> it.
> 
> Signed-off-by: Nick Terrell <terrelln@fb.com>
> ---
>  crypto/zstd.c               |   2 +-
>  fs/btrfs/zstd.c             |   2 +-
>  fs/f2fs/compress.c          |   2 +-
>  fs/squashfs/zstd_wrapper.c  |   2 +-
>  include/linux/zstd_compat.h | 116 ++++++++++++++++++++++++++++++++++++
>  lib/decompress_unzstd.c     |   2 +-
>  6 files changed, 121 insertions(+), 5 deletions(-)
>  create mode 100644 include/linux/zstd_compat.h
> 
> diff --git a/crypto/zstd.c b/crypto/zstd.c
> index 1a3309f066f7..dcda3cad3b5c 100644
> --- a/crypto/zstd.c
> +++ b/crypto/zstd.c
> @@ -11,7 +11,7 @@
>  #include <linux/module.h>
>  #include <linux/net.h>
>  #include <linux/vmalloc.h>
> -#include <linux/zstd.h>
> +#include <linux/zstd_compat.h>
>  #include <crypto/internal/scompress.h>
>  
>  
> diff --git a/fs/btrfs/zstd.c b/fs/btrfs/zstd.c
> index 9a4871636c6c..a7367ff573d4 100644
> --- a/fs/btrfs/zstd.c
> +++ b/fs/btrfs/zstd.c
> @@ -16,7 +16,7 @@
>  #include <linux/refcount.h>
>  #include <linux/sched.h>
>  #include <linux/slab.h>
> -#include <linux/zstd.h>
> +#include <linux/zstd_compat.h>
>  #include "misc.h"
>  #include "compression.h"
>  #include "ctree.h"
> diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
> index 14262e0f1cd6..57a6360b9827 100644
> --- a/fs/f2fs/compress.c
> +++ b/fs/f2fs/compress.c
> @@ -11,7 +11,7 @@
>  #include <linux/backing-dev.h>
>  #include <linux/lzo.h>
>  #include <linux/lz4.h>
> -#include <linux/zstd.h>
> +#include <linux/zstd_compat.h>
>  
>  #include "f2fs.h"
>  #include "node.h"
> diff --git a/fs/squashfs/zstd_wrapper.c b/fs/squashfs/zstd_wrapper.c
> index b7cb1faa652d..f8c512a6204e 100644
> --- a/fs/squashfs/zstd_wrapper.c
> +++ b/fs/squashfs/zstd_wrapper.c
> @@ -11,7 +11,7 @@
>  #include <linux/mutex.h>
>  #include <linux/bio.h>
>  #include <linux/slab.h>
> -#include <linux/zstd.h>
> +#include <linux/zstd_compat.h>
>  #include <linux/vmalloc.h>
>  
>  #include "squashfs_fs.h"
> diff --git a/include/linux/zstd_compat.h b/include/linux/zstd_compat.h
> new file mode 100644
> index 000000000000..cda9208bf04a
> --- /dev/null
> +++ b/include/linux/zstd_compat.h
> @@ -0,0 +1,116 @@
> +/*
> + * Copyright (c) 2016-present, Facebook, Inc.
> + * All rights reserved.
> + *
> + * This source code is licensed under the BSD-style license found in the
> + * LICENSE file in the root directory of https://github.com/facebook/zstd.
> + * An additional grant of patent rights can be found in the PATENTS file in the
> + * same directory.
> + *
> + * 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. This program is dual-licensed; you may select
> + * either version 2 of the GNU General Public License ("GPL") or BSD license
> + * ("BSD").
> + */
> +
> +#ifndef ZSTD_COMPAT_H
> +#define ZSTD_COMPAT_H
> +
> +#include <linux/zstd.h>
> +
> +#if defined(ZSTD_VERSION_NUMBER) && (ZSTD_VERSION_NUMBER >= 10406)
> +/*
> + * This header provides backwards compatibility for the zstd-1.4.6 library
> + * upgrade. This header allows us to upgrade the zstd library version without
> + * modifying any callers. Then we will migrate callers from the compatibility
> + * wrapper one at a time until none remain. At which point we will delete this
> + * header.
> + *
> + * It is temporary and will be deleted once the upgrade is complete.
> + */
> +
> +#include <linux/zstd_errors.h>
> +
> +static inline size_t ZSTD_CCtxWorkspaceBound(ZSTD_compressionParameters compression_params)
> +{
> +    return ZSTD_estimateCCtxSize_usingCParams(compression_params);
> +}
> +
> +static inline size_t ZSTD_CStreamWorkspaceBound(ZSTD_compressionParameters compression_params)
> +{
> +    return ZSTD_estimateCStreamSize_usingCParams(compression_params);
> +}
> +
> +static inline size_t ZSTD_DCtxWorkspaceBound(void)
> +{
> +    return ZSTD_estimateDCtxSize();
> +}
> +
> +static inline size_t ZSTD_DStreamWorkspaceBound(unsigned long long window_size)
> +{
> +    return ZSTD_estimateDStreamSize(window_size);
> +}
> +
> +static inline ZSTD_CCtx* ZSTD_initCCtx(void* wksp, size_t wksp_size)
> +{
> +    if (wksp == NULL)
> +        return NULL;
> +    return ZSTD_initStaticCCtx(wksp, wksp_size);
> +}
> +
> +static inline ZSTD_CStream* ZSTD_initCStream_compat(ZSTD_parameters params, uint64_t pledged_src_size, void* wksp, size_t wksp_size)
> +{
> +    ZSTD_CStream* cstream;
> +    size_t ret;
> +
> +    if (wksp == NULL)
> +        return NULL;
> +
> +    cstream = ZSTD_initStaticCStream(wksp, wksp_size);
> +    if (cstream == NULL)
> +        return NULL;
> +
> +    /* 0 means unknown in old API but means 0 in new API */
> +    if (pledged_src_size == 0)
> +        pledged_src_size = ZSTD_CONTENTSIZE_UNKNOWN;
> +
> +    ret = ZSTD_initCStream_advanced(cstream, NULL, 0, params, pledged_src_size);
> +    if (ZSTD_isError(ret))
> +        return NULL;
> +
> +    return cstream;
> +}
> +#define ZSTD_initCStream ZSTD_initCStream_compat
> +
> +static inline ZSTD_DCtx* ZSTD_initDCtx(void* wksp, size_t wksp_size)
> +{
> +    if (wksp == NULL)
> +        return NULL;
> +    return ZSTD_initStaticDCtx(wksp, wksp_size);
> +}
> +
> +static inline ZSTD_DStream* ZSTD_initDStream_compat(unsigned long long window_size, void* wksp, size_t wksp_size)
> +{
> +    if (wksp == NULL)
> +        return NULL;
> +    (void)window_size;
> +    return ZSTD_initStaticDStream(wksp, wksp_size);
> +}
> +#define ZSTD_initDStream ZSTD_initDStream_compat
> +
> +typedef ZSTD_frameHeader ZSTD_frameParams;
> +
> +static inline size_t ZSTD_getFrameParams(ZSTD_frameParams* frame_params, const void* src, size_t src_size)
> +{
> +    return ZSTD_getFrameHeader(frame_params, src, src_size);
> +}
> +
> +static inline size_t ZSTD_compressCCtx_compat(ZSTD_CCtx* cctx, void* dst, size_t dst_capacity, const void* src, size_t src_size, ZSTD_parameters params)
> +{
> +    return ZSTD_compress_advanced(cctx, dst, dst_capacity, src, src_size, NULL, 0, params);
> +}
> +#define ZSTD_compressCCtx ZSTD_compressCCtx_compat
> +
> +#endif /* ZSTD_VERSION_NUMBER >= 10406 */
> +#endif /* ZSTD_COMPAT_H */
> diff --git a/lib/decompress_unzstd.c b/lib/decompress_unzstd.c
> index 790abc472f5b..6bb805aeec08 100644
> --- a/lib/decompress_unzstd.c
> +++ b/lib/decompress_unzstd.c
> @@ -77,7 +77,7 @@
>  
>  #include <linux/decompress/mm.h>
>  #include <linux/kernel.h>
> -#include <linux/zstd.h>
> +#include <linux/zstd_compat.h>
>  
>  /* 128MB is the maximum window size supported by zstd. */
>  #define ZSTD_WINDOWSIZE_MAX	(1 << ZSTD_WINDOWLOG_MAX)
> -- 
> 2.28.0
> 
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