Re: [PATCH 7/9] nfsd: factor out hash functions for export caches.

["J. Bruce Fields" <bfields@fieldses.org>]

On Wed, Feb 03, 2010 at 05:31:31PM +1100, NeilBrown wrote:
> Both the _lookup and the _update functions for these two caches
> independently calculate the hash of the key.
> So factor out that code for improved reuse.

Applied.--b.

> 
> Signed-off-by: NeilBrown <neilb@suse.de>
> ---
>  fs/nfsd/export.c |   40 +++++++++++++++++++++++-----------------
>  1 files changed, 23 insertions(+), 17 deletions(-)
> 
> diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c
> index c487810..cb8766c 100644
> --- a/fs/nfsd/export.c
> +++ b/fs/nfsd/export.c
> @@ -258,10 +258,9 @@ static struct cache_detail svc_expkey_cache = {
>  	.alloc		= expkey_alloc,
>  };
>  
> -static struct svc_expkey *
> -svc_expkey_lookup(struct svc_expkey *item)
> +static int
> +svc_expkey_hash(struct svc_expkey *item)
>  {
> -	struct cache_head *ch;
>  	int hash = item->ek_fsidtype;
>  	char * cp = (char*)item->ek_fsid;
>  	int len = key_len(item->ek_fsidtype);
> @@ -269,6 +268,14 @@ svc_expkey_lookup(struct svc_expkey *item)
>  	hash ^= hash_mem(cp, len, EXPKEY_HASHBITS);
>  	hash ^= hash_ptr(item->ek_client, EXPKEY_HASHBITS);
>  	hash &= EXPKEY_HASHMASK;
> +	return hash;
> +}
> +
> +static struct svc_expkey *
> +svc_expkey_lookup(struct svc_expkey *item)
> +{
> +	struct cache_head *ch;
> +	int hash = svc_expkey_hash(item);
>  
>  	ch = sunrpc_cache_lookup(&svc_expkey_cache, &item->h,
>  				 hash);
> @@ -282,13 +289,7 @@ static struct svc_expkey *
>  svc_expkey_update(struct svc_expkey *new, struct svc_expkey *old)
>  {
>  	struct cache_head *ch;
> -	int hash = new->ek_fsidtype;
> -	char * cp = (char*)new->ek_fsid;
> -	int len = key_len(new->ek_fsidtype);
> -
> -	hash ^= hash_mem(cp, len, EXPKEY_HASHBITS);
> -	hash ^= hash_ptr(new->ek_client, EXPKEY_HASHBITS);
> -	hash &= EXPKEY_HASHMASK;
> +	int hash = svc_expkey_hash(new);
>  
>  	ch = sunrpc_cache_update(&svc_expkey_cache, &new->h,
>  				 &old->h, hash);
> @@ -737,14 +738,22 @@ struct cache_detail svc_export_cache = {
>  	.alloc		= svc_export_alloc,
>  };
>  
> -static struct svc_export *
> -svc_export_lookup(struct svc_export *exp)
> +static int
> +svc_export_hash(struct svc_export *exp)
>  {
> -	struct cache_head *ch;
>  	int hash;
> +
>  	hash = hash_ptr(exp->ex_client, EXPORT_HASHBITS);
>  	hash ^= hash_ptr(exp->ex_path.dentry, EXPORT_HASHBITS);
>  	hash ^= hash_ptr(exp->ex_path.mnt, EXPORT_HASHBITS);
> +	return hash;
> +}
> +
> +static struct svc_export *
> +svc_export_lookup(struct svc_export *exp)
> +{
> +	struct cache_head *ch;
> +	int hash = svc_export_hash(exp);
>  
>  	ch = sunrpc_cache_lookup(&svc_export_cache, &exp->h,
>  				 hash);
> @@ -758,10 +767,7 @@ static struct svc_export *
>  svc_export_update(struct svc_export *new, struct svc_export *old)
>  {
>  	struct cache_head *ch;
> -	int hash;
> -	hash = hash_ptr(old->ex_client, EXPORT_HASHBITS);
> -	hash ^= hash_ptr(old->ex_path.dentry, EXPORT_HASHBITS);
> -	hash ^= hash_ptr(old->ex_path.mnt, EXPORT_HASHBITS);
> +	int hash = svc_export_hash(old);
>  
>  	ch = sunrpc_cache_update(&svc_export_cache, &new->h,
>  				 &old->h,
> 
>