Re: [PATCH v7 07/16] net,9p: use new hashtable implementation

Mathieu Desnoyers
2012-10-29T12:15:11Z

* Sasha Levin (levinsasha928@gmail.com) wrote:
> Switch 9p error table to use the new hashtable implementation. This reduces the amount of
> generic unrelated code in 9p.
>
> Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
> ---
> net/9p/error.c | 21 ++++++++++-----------
> 1 file changed, 10 insertions(+), 11 deletions(-)
>
> diff --git a/net/9p/error.c b/net/9p/error.c
> index 2ab2de7..a5cc7dd 100644
> --- a/net/9p/error.c
> +++ b/net/9p/error.c
> @@ -34,7 +34,7 @@
> #include <linux/jhash.h>
> #include <linux/errno.h>
> #include <net/9p/9p.h>
> -
> +#include <linux/hashtable.h>

missing newline.

> /**
> * struct errormap - map string errors from Plan 9 to Linux numeric ids
> * @name: string sent over 9P
> @@ -50,8 +50,8 @@ struct errormap {
> struct hlist_node list;
> };
>
> -#define ERRHASHSZ 32
> -static struct hlist_head hash_errmap[ERRHASHSZ];
> +#define ERR_HASH_BITS 5
> +static DEFINE_HASHTABLE(hash_errmap, ERR_HASH_BITS);
>
> /* FixMe - reduce to a reasonable size */
> static struct errormap errmap[] = {
> @@ -193,18 +193,17 @@ static struct errormap errmap[] = {
> int p9_error_init(void)
> {
> struct errormap *c;
> - int bucket;
> + u32 hash;
>
> /* initialize hash table */
> - for (bucket = 0; bucket < ERRHASHSZ; bucket++)
> - INIT_HLIST_HEAD(&hash_errmap[bucket]);
> + hash_init(hash_errmap);

As for most of the other patches in this series, the hash_init is
redundant for a statically defined hash table.

Thanks,

Mathieu

>
> /* load initial error map into hash table */
> for (c = errmap; c->name != NULL; c++) {
> c->namelen = strlen(c->name);
> - bucket = jhash(c->name, c->namelen, 0) % ERRHASHSZ;
> + hash = jhash(c->name, c->namelen, 0);
> INIT_HLIST_NODE(&c->list);
> - hlist_add_head(&c->list, &hash_errmap[bucket]);
> + hash_add(hash_errmap, &c->list, hash);
> }
>
> return 1;
> @@ -223,13 +222,13 @@ int p9_errstr2errno(char *errstr, int len)
> int errno;
> struct hlist_node *p;
> struct errormap *c;
> - int bucket;
> + u32 hash;
>
> errno = 0;
> p = NULL;
> c = NULL;
> - bucket = jhash(errstr, len, 0) % ERRHASHSZ;
> - hlist_for_each_entry(c, p, &hash_errmap[bucket], list) {
> + hash = jhash(errstr, len, 0);
> + hash_for_each_possible(hash_errmap, c, p, list, hash) {
> if (c->namelen == len && !memcmp(c->name, errstr, len)) {
> errno = c->val;
> break;
> --
> 1.7.12.4
>

--
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.