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From:   Gabriel Krisman Bertazi <krisman@collabora.com>
To:     Christoph Hellwig <hch@lst.de>
Cc:     Shreeya Patel <shreeya.patel@collabora.com>,
        linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org,
        linux-f2fs-devel@lists.sourceforge.net
Subject: Re: [PATCH 10/11] unicode: Add utf8-data module
Organization: Collabora
References: <20210915070006.954653-1-hch@lst.de>
        <20210915070006.954653-11-hch@lst.de>
Date:   Tue, 12 Oct 2021 08:25:23 -0300
In-Reply-To: <20210915070006.954653-11-hch@lst.de> (Christoph Hellwig's
        message of "Wed, 15 Sep 2021 09:00:05 +0200")
Message-ID: <87wnmipjrw.fsf@collabora.com>
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux)
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

Christoph Hellwig <hch@lst.de> writes:

> utf8data.h contains a large database table which is an auto-generated
> decodification trie for the unicode normalization functions.
>
> Allow building it into a separate module.
>
> Based on a patch from Shreeya Patel <shreeya.patel@collabora.com>.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  fs/unicode/Kconfig                            | 13 ++++-
>  fs/unicode/Makefile                           | 13 ++---
>  fs/unicode/mkutf8data.c                       | 24 ++++++++--
>  fs/unicode/utf8-core.c                        | 35 +++++++++++---
>  fs/unicode/utf8-norm.c                        | 48 ++++---------------
>  fs/unicode/utf8-selftest.c                    | 16 +++----
>  ...{utf8data.h_shipped => utf8data.c_shipped} | 22 +++++++--
>  fs/unicode/utf8n.h                            | 40 ++++++++--------
>  include/linux/unicode.h                       |  2 +
>  9 files changed, 123 insertions(+), 90 deletions(-)
>  rename fs/unicode/{utf8data.h_shipped => utf8data.c_shipped} (99%)
>
> diff --git a/fs/unicode/Kconfig b/fs/unicode/Kconfig
> index 2c27b9a5cd6ce..610d7bc05d6e3 100644
> --- a/fs/unicode/Kconfig
> +++ b/fs/unicode/Kconfig
> @@ -8,7 +8,16 @@ config UNICODE
>  	  Say Y here to enable UTF-8 NFD normalization and NFD+CF casefolding
>  	  support.
>  
> +config UNICODE_UTF8_DATA
> +	tristate "UTF-8 normalization and casefolding tables"
> +	depends on UNICODE
> +	default UNICODE
> +	help
> +	  This contains a large table of case foldings, which can be loaded as
> +	  a separate module if you say M here.  To be on the safe side stick
> +	  to the default of Y.  Saying N here makes no sense, if you do not want
> +	  utf8 casefolding support, disable CONFIG_UNICODE instead.
> +
>  config UNICODE_NORMALIZATION_SELFTEST
>  	tristate "Test UTF-8 normalization support"
> -	depends on UNICODE
> -	default n
> +	depends on UNICODE_UTF8_DATA
> diff --git a/fs/unicode/Makefile b/fs/unicode/Makefile
> index b88aecc865502..2f9d9188852b5 100644
> --- a/fs/unicode/Makefile
> +++ b/fs/unicode/Makefile
> @@ -2,14 +2,15 @@
>  
>  obj-$(CONFIG_UNICODE) += unicode.o
>  obj-$(CONFIG_UNICODE_NORMALIZATION_SELFTEST) += utf8-selftest.o
> +obj-$(CONFIG_UNICODE_UTF8_DATA) += utf8data.o
>  
>  unicode-y := utf8-norm.o utf8-core.o
>  
> -$(obj)/utf8-norm.o: $(obj)/utf8data.h
> +$(obj)/utf8-data.o: $(obj)/utf8data.c
>  
> -# In the normal build, the checked-in utf8data.h is just shipped.
> +# In the normal build, the checked-in utf8data.c is just shipped.
>  #
> -# To generate utf8data.h from UCD, put *.txt files in this directory
> +# To generate utf8data.c from UCD, put *.txt files in this directory
>  # and pass REGENERATE_UTF8DATA=1 from the command line.
>  ifdef REGENERATE_UTF8DATA
>  
> @@ -24,15 +25,15 @@ quiet_cmd_utf8data = GEN     $@
>  		-t $(srctree)/$(src)/NormalizationTest.txt \
>  		-o $@
>  
> -$(obj)/utf8data.h: $(obj)/mkutf8data $(filter %.txt, $(cmd_utf8data)) FORCE
> +$(obj)/utf8data.c: $(obj)/mkutf8data $(filter %.txt, $(cmd_utf8data)) FORCE
>  	$(call if_changed,utf8data)
>  
>  else
>  
> -$(obj)/utf8data.h: $(src)/utf8data.h_shipped FORCE
> +$(obj)/utf8data.c: $(src)/utf8data.c_shipped FORCE
>  	$(call if_changed,shipped)
>  
>  endif
>  
> -targets += utf8data.h
> +targets += utf8data.c
>  hostprogs += mkutf8data
> diff --git a/fs/unicode/mkutf8data.c b/fs/unicode/mkutf8data.c
> index ff2025ac5a325..bc1a7c8b5c8df 100644
> --- a/fs/unicode/mkutf8data.c
> +++ b/fs/unicode/mkutf8data.c
> @@ -3287,12 +3287,10 @@ static void write_file(void)
>  		open_fail(utf8_name, errno);
>  
>  	fprintf(file, "/* This file is generated code, do not edit. */\n");
> -	fprintf(file, "#ifndef __INCLUDED_FROM_UTF8NORM_C__\n");
> -	fprintf(file, "#error Only nls_utf8-norm.c should include this file.\n");
> -	fprintf(file, "#endif\n");
>  	fprintf(file, "\n");
> -	fprintf(file, "static const unsigned int utf8vers = %#x;\n",
> -		unicode_maxage);
> +	fprintf(file, "#include <linux/module.h>\n");
> +	fprintf(file, "#include <linux/kernel.h>\n");
> +	fprintf(file, "#include \"utf8n.h\"\n");
>  	fprintf(file, "\n");
>  	fprintf(file, "static const unsigned int utf8agetab[] = {\n");
>  	for (i = 0; i != ages_count; i++)
> @@ -3339,6 +3337,22 @@ static void write_file(void)
>  		fprintf(file, "\n");
>  	}
>  	fprintf(file, "};\n");
> +	fprintf(file, "\n");
> +	fprintf(file, "struct utf8data_table utf8_data_table = {\n");
> +	fprintf(file, "\t.utf8agetab = utf8agetab,\n");
> +	fprintf(file, "\t.utf8agetab_size = ARRAY_SIZE(utf8agetab),\n");
> +	fprintf(file, "\n");
> +	fprintf(file, "\t.utf8nfdicfdata = utf8nfdicfdata,\n");
> +	fprintf(file, "\t.utf8nfdicfdata_size = ARRAY_SIZE(utf8nfdicfdata),\n");
> +	fprintf(file, "\n");
> +	fprintf(file, "\t.utf8nfdidata = utf8nfdidata,\n");
> +	fprintf(file, "\t.utf8nfdidata_size = ARRAY_SIZE(utf8nfdidata),\n");
> +	fprintf(file, "\n");
> +	fprintf(file, "\t.utf8data = utf8data,\n");
> +	fprintf(file, "};\n");
> +	fprintf(file, "EXPORT_SYMBOL_GPL(utf8_data_table);");
> +	fprintf(file, "\n");
> +	fprintf(file, "MODULE_LICENSE(\"GPL v2\");\n");
>  	fclose(file);
>  }
>  
> diff --git a/fs/unicode/utf8-core.c b/fs/unicode/utf8-core.c
> index d9f713d38c0ad..38ca824f10158 100644
> --- a/fs/unicode/utf8-core.c
> +++ b/fs/unicode/utf8-core.c
> @@ -160,25 +160,45 @@ int utf8_normalize(const struct unicode_map *um, const struct qstr *str,
>  }
>  EXPORT_SYMBOL(utf8_normalize);
>  
> +static const struct utf8data *find_table_version(const struct utf8data *table,
> +		size_t nr_entries, unsigned int version)
> +{
> +	size_t i = nr_entries - 1;
> +
> +	while (version < table[i].maxage)
> +		i--;
> +	if (version > table[i].maxage)
> +		return NULL;
> +	return &table[i];
> +}
> +
>  struct unicode_map *utf8_load(unsigned int version)
>  {
>  	struct unicode_map *um;
>  
> -	if (!utf8version_is_supported(version))
> -		return ERR_PTR(-EINVAL);
> -
>  	um = kzalloc(sizeof(struct unicode_map), GFP_KERNEL);
>  	if (!um)
>  		return ERR_PTR(-ENOMEM);
>  	um->version = version;
> -	um->ntab[UTF8_NFDI] = utf8nfdi(version);
> -	if (!um->ntab[UTF8_NFDI])
> +
> +	um->tables = symbol_request(utf8_data_table);
> +	if (!um->tables)
>  		goto out_free_um;
> -	um->ntab[UTF8_NFDICF] = utf8nfdicf(version);
> +
> +	if (!utf8version_is_supported(um, version))
> +		goto out_symbol_put;
> +	um->ntab[UTF8_NFDI] = find_table_version(um->tables->utf8nfdidata,
> +			um->tables->utf8nfdidata_size, um->version);
> +	if (!um->ntab[UTF8_NFDI])
> +		goto out_symbol_put;
> +	um->ntab[UTF8_NFDICF] = find_table_version(um->tables->utf8nfdicfdata,
> +			um->tables->utf8nfdicfdata_size, um->version);
>  	if (!um->ntab[UTF8_NFDICF])
> -		goto out_free_um;
> +		goto out_symbol_put;
>  	return um;
>  
> +out_symbol_put:
> +	symbol_put(um->tables);
>  out_free_um:
>  	kfree(um);
>  	return ERR_PTR(-EINVAL);
> @@ -187,6 +207,7 @@ EXPORT_SYMBOL(utf8_load);
>  
>  void utf8_unload(struct unicode_map *um)
>  {
> +	symbol_put(utf8_data_table);

This triggers a BUG_ON if the symbol isn't loaded/loadable,
i.e. ext4_fill_super fails early.  I'm not sure how to fix it, though.


 Failed to find symbol utf8_data_table
 ------------[ cut here ]------------
 kernel BUG at kernel/module.c:1022!
 invalid opcode: 0000 [#1] SMP
 CPU: 1 PID: 387 Comm: mount Not tainted 5.15.0-rc4-for-next_5.15 #5
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014
 RIP: 0010:__symbol_put+0x88/0x90
 Code: 84 c0 74 26 48 8b 7c 24 10 e8 44 f9 ff ff 65 ff 0d 1d 44 ea 7e 48 8b 44 24 30 65 48 33 04 25 28 00 00 00 75 07 48 83 c4 38 c3 <0f> 0b e8 51 ca a9 00 90 0f 1f 44 00 00 48 63 46 04 48 8d 74

 RSP: 0018:ffffc90000623cc0 EFLAGS: 00010246
 RAX: 0000000000000000 RBX: ffff888102e91490 RCX: 0000000000000000
 RDX: 0000000000000000 RSI: ffff88813b9d7860 RDI: ffff88813b9d7868
 RBP: ffffc90000623de0 R08: 0000000000000000 R09: c0000000ffffefff
 R10: ffffc900006239d8 R11: ffffc900006239d0 R12: 00000000ffffffea
 R13: 0000000000000000 R14: ffff888102e94000 R15: ffff888102e91000
 FS:  00007efcab508800(0000) GS:ffff88813b800000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 00007ff08eec56f4 CR3: 0000000102f31000 CR4: 00000000000006e0
 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
 Call Trace:
  ext4_fill_super+0x289/0x32b0
  ? bdev_name.isra.7+0x53/0xd0
  ? vsnprintf+0x379/0x520
  ? ext4_enable_quotas+0x260/0x260
  ? mount_bdev+0x18a/0x1c0
  ? ext4_enable_quotas+0x260/0x260
  mount_bdev+0x18a/0x1c0
  legacy_get_tree+0x30/0x50
  vfs_get_tree+0x23/0x90
  ? ns_capable_common+0x2b/0x50
  path_mount+0x6da/0xa50
  ? kmem_cache_free+0xf4/0x140
  do_mount+0x75/0x90
  __x64_sys_mount+0xc4/0xe0
  do_syscall_64+0x3a/0xb0
  entry_SYSCALL_64_after_hwframe+0x44/0xae
 RIP: 0033:0x7efcab71f6ba
 Code: 48 8b 0d b1 f7 0b 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 7e f7 0b 00 f7 d8 64 89

 RSP: 002b:00007ffefb824338 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
 RAX: ffffffffffffffda RBX: 00007efcab873264 RCX: 00007efcab71f6ba
 RDX: 000055a2867dad10 RSI: 000055a2867d40f0 RDI: 000055a2867d40d0
 RBP: 000055a2867d3ea0 R08: 0000000000000000 R09: 000055a2867d3010
 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
 R13: 000055a2867d40d0 R14: 000055a2867dad10 R15: 000055a2867d3ea0
 Modules linked in:
 ---[ end trace abcd43d820168730 ]---


>  	kfree(um);
>  }
>  EXPORT_SYMBOL(utf8_unload);
> diff --git a/fs/unicode/utf8-norm.c b/fs/unicode/utf8-norm.c
> index 7c1f28ab31a80..829c7e2ad764a 100644
> --- a/fs/unicode/utf8-norm.c
> +++ b/fs/unicode/utf8-norm.c
> @@ -6,21 +6,12 @@
>  
>  #include "utf8n.h"
>  
> -struct utf8data {
> -	unsigned int maxage;
> -	unsigned int offset;
> -};
> -
> -#define __INCLUDED_FROM_UTF8NORM_C__
> -#include "utf8data.h"
> -#undef __INCLUDED_FROM_UTF8NORM_C__
> -
> -int utf8version_is_supported(unsigned int version)
> +int utf8version_is_supported(const struct unicode_map *um, unsigned int version)
>  {
> -	int i = ARRAY_SIZE(utf8agetab) - 1;
> +	int i = um->tables->utf8agetab_size - 1;
>  
> -	while (i >= 0 && utf8agetab[i] != 0) {
> -		if (version == utf8agetab[i])
> +	while (i >= 0 && um->tables->utf8agetab[i] != 0) {
> +		if (version == um->tables->utf8agetab[i])
>  			return 1;
>  		i--;
>  	}
> @@ -161,7 +152,7 @@ typedef const unsigned char utf8trie_t;
>   * underlying datatype: unsigned char.
>   *
>   * leaf[0]: The unicode version, stored as a generation number that is
> - *          an index into utf8agetab[].  With this we can filter code
> + *          an index into ->utf8agetab[].  With this we can filter code
>   *          points based on the unicode version in which they were
>   *          defined.  The CCC of a non-defined code point is 0.
>   * leaf[1]: Canonical Combining Class. During normalization, we need
> @@ -313,7 +304,7 @@ static utf8leaf_t *utf8nlookup(const struct unicode_map *um,
>  		enum utf8_normalization n, unsigned char *hangul, const char *s,
>  		size_t len)
>  {
> -	utf8trie_t	*trie = utf8data + um->ntab[n]->offset;
> +	utf8trie_t	*trie = um->tables->utf8data + um->ntab[n]->offset;
>  	int		offlen;
>  	int		offset;
>  	int		mask;
> @@ -404,7 +395,8 @@ ssize_t utf8nlen(const struct unicode_map *um, enum utf8_normalization n,
>  		leaf = utf8nlookup(um, n, hangul, s, len);
>  		if (!leaf)
>  			return -1;
> -		if (utf8agetab[LEAF_GEN(leaf)] > um->ntab[n]->maxage)
> +		if (um->tables->utf8agetab[LEAF_GEN(leaf)] >
> +		    um->ntab[n]->maxage)
>  			ret += utf8clen(s);
>  		else if (LEAF_CCC(leaf) == DECOMPOSE)
>  			ret += strlen(LEAF_STR(leaf));
> @@ -520,7 +512,7 @@ int utf8byte(struct utf8cursor *u8c)
>  
>  		ccc = LEAF_CCC(leaf);
>  		/* Characters that are too new have CCC 0. */
> -		if (utf8agetab[LEAF_GEN(leaf)] >
> +		if (u8c->um->tables->utf8agetab[LEAF_GEN(leaf)] >
>  		    u8c->um->ntab[u8c->n]->maxage) {
>  			ccc = STOPPER;
>  		} else if (ccc == DECOMPOSE) {
> @@ -597,25 +589,3 @@ int utf8byte(struct utf8cursor *u8c)
>  	}
>  }
>  EXPORT_SYMBOL(utf8byte);
> -
> -const struct utf8data *utf8nfdi(unsigned int maxage)
> -{
> -	int i = ARRAY_SIZE(utf8nfdidata) - 1;
> -
> -	while (maxage < utf8nfdidata[i].maxage)
> -		i--;
> -	if (maxage > utf8nfdidata[i].maxage)
> -		return NULL;
> -	return &utf8nfdidata[i];
> -}
> -
> -const struct utf8data *utf8nfdicf(unsigned int maxage)
> -{
> -	int i = ARRAY_SIZE(utf8nfdicfdata) - 1;
> -
> -	while (maxage < utf8nfdicfdata[i].maxage)
> -		i--;
> -	if (maxage > utf8nfdicfdata[i].maxage)
> -		return NULL;
> -	return &utf8nfdicfdata[i];
> -}
> diff --git a/fs/unicode/utf8-selftest.c b/fs/unicode/utf8-selftest.c
> index cfa3832b75f42..eb2bbdd688d71 100644
> --- a/fs/unicode/utf8-selftest.c
> +++ b/fs/unicode/utf8-selftest.c
> @@ -255,21 +255,21 @@ static void check_utf8_comparisons(struct unicode_map *table)
>  	}
>  }
>  
> -static void check_supported_versions(void)
> +static void check_supported_versions(struct unicode_map *um)
>  {
>  	/* Unicode 7.0.0 should be supported. */
> -	test(utf8version_is_supported(UNICODE_AGE(7, 0, 0)));
> +	test(utf8version_is_supported(um, UNICODE_AGE(7, 0, 0)));
>  
>  	/* Unicode 9.0.0 should be supported. */
> -	test(utf8version_is_supported(UNICODE_AGE(9, 0, 0)));
> +	test(utf8version_is_supported(um, UNICODE_AGE(9, 0, 0)));
>  
>  	/* Unicode 1x.0.0 (the latest version) should be supported. */
> -	test(utf8version_is_supported(UTF8_LATEST));
> +	test(utf8version_is_supported(um, UTF8_LATEST));
>  
>  	/* Next versions don't exist. */
> -	test(!utf8version_is_supported(UNICODE_AGE(13, 0, 0)));
> -	test(!utf8version_is_supported(UNICODE_AGE(0, 0, 0)));
> -	test(!utf8version_is_supported(UNICODE_AGE(-1, -1, -1)));
> +	test(!utf8version_is_supported(um, UNICODE_AGE(13, 0, 0)));
> +	test(!utf8version_is_supported(um, UNICODE_AGE(0, 0, 0)));
> +	test(!utf8version_is_supported(um, UNICODE_AGE(-1, -1, -1)));
>  }
>  
>  static int __init init_test_ucd(void)
> @@ -285,7 +285,7 @@ static int __init init_test_ucd(void)
>  		return PTR_ERR(um);
>  	}
>  
> -	check_supported_versions();
> +	check_supported_versions(um);
>  	check_utf8_nfdi(um);
>  	check_utf8_nfdicf(um);
>  	check_utf8_comparisons(um);
> diff --git a/fs/unicode/utf8data.h_shipped b/fs/unicode/utf8data.c_shipped
> similarity index 99%
> rename from fs/unicode/utf8data.h_shipped
> rename to fs/unicode/utf8data.c_shipped
> index 76e4f0e1b0891..d9b62901aa96b 100644
> --- a/fs/unicode/utf8data.h_shipped
> +++ b/fs/unicode/utf8data.c_shipped
> @@ -1,9 +1,8 @@
>  /* This file is generated code, do not edit. */
> -#ifndef __INCLUDED_FROM_UTF8NORM_C__
> -#error Only nls_utf8-norm.c should include this file.
> -#endif
>  
> -static const unsigned int utf8vers = 0xc0100;
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include "utf8n.h"
>  
>  static const unsigned int utf8agetab[] = {
>  	0,
> @@ -4107,3 +4106,18 @@ static const unsigned char utf8data[64256] = {
>  	0x52,0x04,0x00,0x00,0x11,0x04,0x00,0x00,0x02,0x00,0xcf,0x86,0xcf,0x06,0x02,0x00,
>  	0x81,0x80,0xcf,0x86,0x85,0x84,0xcf,0x86,0xcf,0x06,0x02,0x00,0x00,0x00,0x00,0x00
>  };
> +
> +struct utf8data_table utf8_data_table = {
> +	.utf8agetab = utf8agetab,
> +	.utf8agetab_size = ARRAY_SIZE(utf8agetab),
> +
> +	.utf8nfdicfdata = utf8nfdicfdata,
> +	.utf8nfdicfdata_size = ARRAY_SIZE(utf8nfdicfdata),
> +
> +	.utf8nfdidata = utf8nfdidata,
> +	.utf8nfdidata_size = ARRAY_SIZE(utf8nfdidata),
> +
> +	.utf8data = utf8data,
> +};
> +EXPORT_SYMBOL_GPL(utf8_data_table);
> +MODULE_LICENSE("GPL v2");
> diff --git a/fs/unicode/utf8n.h b/fs/unicode/utf8n.h
> index 206c89f0dbf71..bd00d587747a7 100644
> --- a/fs/unicode/utf8n.h
> +++ b/fs/unicode/utf8n.h
> @@ -13,25 +13,7 @@
>  #include <linux/module.h>
>  #include <linux/unicode.h>
>  
> -int utf8version_is_supported(unsigned int version);
> -
> -/*
> - * Look for the correct const struct utf8data for a unicode version.
> - * Returns NULL if the version requested is too new.
> - *
> - * Two normalization forms are supported: nfdi and nfdicf.
> - *
> - * nfdi:
> - *  - Apply unicode normalization form NFD.
> - *  - Remove any Default_Ignorable_Code_Point.
> - *
> - * nfdicf:
> - *  - Apply unicode normalization form NFD.
> - *  - Remove any Default_Ignorable_Code_Point.
> - *  - Apply a full casefold (C + F).
> - */
> -extern const struct utf8data *utf8nfdi(unsigned int maxage);
> -extern const struct utf8data *utf8nfdicf(unsigned int maxage);
> +int utf8version_is_supported(const struct unicode_map *um, unsigned int version);
>  
>  /*
>   * Determine the length of the normalized from of the string,
> @@ -78,4 +60,24 @@ int utf8ncursor(struct utf8cursor *u8c, const struct unicode_map *um,
>   */
>  extern int utf8byte(struct utf8cursor *u8c);
>  
> +struct utf8data {
> +	unsigned int maxage;
> +	unsigned int offset;
> +};
> +
> +struct utf8data_table {
> +	const unsigned int *utf8agetab;
> +	int utf8agetab_size;
> +
> +	const struct utf8data *utf8nfdicfdata;
> +	int utf8nfdicfdata_size;
> +
> +	const struct utf8data *utf8nfdidata;
> +	int utf8nfdidata_size;
> +
> +	const unsigned char *utf8data;
> +};
> +
> +extern struct utf8data_table utf8_data_table;
> +
>  #endif /* UTF8NORM_H */
> diff --git a/include/linux/unicode.h b/include/linux/unicode.h
> index 526ca8b8391a5..4d39e6e11a950 100644
> --- a/include/linux/unicode.h
> +++ b/include/linux/unicode.h
> @@ -6,6 +6,7 @@
>  #include <linux/dcache.h>
>  
>  struct utf8data;
> +struct utf8data_table;
>  
>  #define UNICODE_MAJ_SHIFT		16
>  #define UNICODE_MIN_SHIFT		8
> @@ -49,6 +50,7 @@ enum utf8_normalization {
>  struct unicode_map {
>  	unsigned int version;
>  	const struct utf8data *ntab[UTF8_NMAX];
> +	const struct utf8data_table *tables;
>  };
>  
>  int utf8_validate(const struct unicode_map *um, const struct qstr *str);

-- 
Gabriel Krisman Bertazi