Re: [PATCH v9 1/4] unicode: Add utf8_casefold_hash

Gabriel Krisman Bertazi
2020-06-24T05:13:24Z

Daniel Rosenberg <drosen@google.com> writes:

> This adds a case insensitive hash function to allow taking the hash
> without needing to allocate a casefolded copy of the string.
>
> Signed-off-by: Daniel Rosenberg <drosen@google.com>
> ---
> fs/unicode/utf8-core.c | 23 ++++++++++++++++++++++-
> include/linux/unicode.h | 3 +++
> 2 files changed, 25 insertions(+), 1 deletion(-)
>
> diff --git a/fs/unicode/utf8-core.c b/fs/unicode/utf8-core.c
> index 2a878b739115d..90656b9980720 100644
> --- a/fs/unicode/utf8-core.c
> +++ b/fs/unicode/utf8-core.c
> @@ -6,6 +6,7 @@
> #include <linux/parser.h>
> #include <linux/errno.h>
> #include <linux/unicode.h>
> +#include <linux/stringhash.h>
>
> #include "utf8n.h"
>
> @@ -122,9 +123,29 @@ int utf8_casefold(const struct unicode_map *um, const struct qstr *str,
> }
> return -EINVAL;
> }
> -
> EXPORT_SYMBOL(utf8_casefold);
>
> +int utf8_casefold_hash(const struct unicode_map *um, const void *salt,
> + struct qstr *str)
> +{
> + const struct utf8data *data = utf8nfdicf(um->version);
> + struct utf8cursor cur;
> + int c;
> + unsigned long hash = init_name_hash(salt);
> +
> + if (utf8ncursor(&cur, data, str->name, str->len) < 0)
> + return -EINVAL;
> +
> + while ((c = utf8byte(&cur))) {
> + if (c < 0)
> + return c;

Return -EINVAL here to match other unicode functions, since utf8byte
will return -1 on a binary blob, which doesn't make sense for this.

Other than that, looks good to me.

Reviewed-by: Gabriel Krisman Bertazi <krisman@collabora.com>

> + hash = partial_name_hash((unsigned char)c, hash);
> + }
> + str->hash = end_name_hash(hash);
> + return 0;
> +}
> +EXPORT_SYMBOL(utf8_casefold_hash);
> +
> int utf8_normalize(const struct unicode_map *um, const struct qstr *str,
> unsigned char *dest, size_t dlen)
> {
> diff --git a/include/linux/unicode.h b/include/linux/unicode.h
> index 990aa97d80496..74484d44c7554 100644
> --- a/include/linux/unicode.h
> +++ b/include/linux/unicode.h
> @@ -27,6 +27,9 @@ int utf8_normalize(const struct unicode_map *um, const struct qstr *str,
> int utf8_casefold(const struct unicode_map *um, const struct qstr *str,
> unsigned char *dest, size_t dlen);
>
> +int utf8_casefold_hash(const struct unicode_map *um, const void *salt,
> + struct qstr *str);
> +
> struct unicode_map *utf8_load(const char *version);
> void utf8_unload(struct unicode_map *um);

--
Gabriel Krisman Bertazi