On Thu, May 11, 2017 at 12:42 PM, Leno Hou <leno...@gmail.com> wrote:
> This patch optimized the code by previously getpos function call.
> Therefore, It's takes the convenience to understand logic of code.
>
> v2:
> - getpos() returns errorno if not found the key
>
> v1:
> - cleanup code by using getpos()
FWIW:
Reviewed-by: Andy Shevchenko <andy.shevche...@gmail.com>
>
> Signed-off-by: Leno Hou <leno...@gmail.com>
> ---
> lib/btree.c | 50 +++++++++++++++++++++-----------------------------
> 1 file changed, 21 insertions(+), 29 deletions(-)
>
> diff --git a/lib/btree.c b/lib/btree.c
> index f93a945..8604773 100644
> --- a/lib/btree.c
> +++ b/lib/btree.c
> @@ -238,6 +238,18 @@ static int keyzero(struct btree_geo *geo, unsigned long
> *key)
> return 1;
> }
>
> +static int getpos(struct btree_geo *geo, unsigned long *node,
> + unsigned long *key)
> +{
> + unsigned int i;
> +
> + for (i = 0; i < geo->no_pairs; i++) {
> + if (keycmp(geo, node, i, key) <= 0)
> + return i;
> + }
> + return -ENOENT;
> +}
> +
> void *btree_lookup(struct btree_head *head, struct btree_geo *geo,
> unsigned long *key)
> {
> @@ -248,10 +260,8 @@ void *btree_lookup(struct btree_head *head, struct
> btree_geo *geo,
> return NULL;
>
> for ( ; height > 1; height--) {
> - for (i = 0; i < geo->no_pairs; i++)
> - if (keycmp(geo, node, i, key) <= 0)
> - break;
> - if (i == geo->no_pairs)
> + i = getpos(geo, node, key);
> + if (i < 0)
> return NULL;
> node = bval(geo, node, i);
> if (!node)
> @@ -278,10 +288,8 @@ int btree_update(struct btree_head *head, struct
> btree_geo *geo,
> return -ENOENT;
>
> for ( ; height > 1; height--) {
> - for (i = 0; i < geo->no_pairs; i++)
> - if (keycmp(geo, node, i, key) <= 0)
> - break;
> - if (i == geo->no_pairs)
> + i = getpos(geo, node, key);
> + if (i < 0)
> return -ENOENT;
> node = bval(geo, node, i);
> if (!node)
> @@ -326,10 +334,8 @@ void *btree_get_prev(struct btree_head *head, struct
> btree_geo *geo,
>
> node = head->node;
> for (height = head->height ; height > 1; height--) {
> - for (i = 0; i < geo->no_pairs; i++)
> - if (keycmp(geo, node, i, key) <= 0)
> - break;
> - if (i == geo->no_pairs)
> + i = getpos(geo, node, key);
> + if (i < 0)
> goto miss;
> oldnode = node;
> node = bval(geo, node, i);
> @@ -360,18 +366,6 @@ void *btree_get_prev(struct btree_head *head, struct
> btree_geo *geo,
> }
> EXPORT_SYMBOL_GPL(btree_get_prev);
>
> -static int getpos(struct btree_geo *geo, unsigned long *node,
> - unsigned long *key)
> -{
> - int i;
> -
> - for (i = 0; i < geo->no_pairs; i++) {
> - if (keycmp(geo, node, i, key) <= 0)
> - break;
> - }
> - return i;
> -}
> -
> static int getfill(struct btree_geo *geo, unsigned long *node, int start)
> {
> int i;
> @@ -392,11 +386,9 @@ static unsigned long *find_level(struct btree_head
> *head, struct btree_geo *geo,
> int i, height;
>
> for (height = head->height; height > level; height--) {
> - for (i = 0; i < geo->no_pairs; i++)
> - if (keycmp(geo, node, i, key) <= 0)
> - break;
> + i = getpos(geo, node, key);
>
> - if ((i == geo->no_pairs) || !bval(geo, node, i)) {
> + if ((i < 0) || !bval(geo, node, i)) {
> /* right-most key is too large, update it */
> /* FIXME: If the right-most key on higher levels is
> * always zero, this wouldn't be necessary. */
> @@ -466,7 +458,7 @@ static int btree_insert_level(struct btree_head *head,
> struct btree_geo *geo,
> /* two identical keys are not allowed */
> BUG_ON(pos < fill && keycmp(geo, node, pos, key) == 0);
>
> - if (fill == geo->no_pairs) {
> + if (fill < 0) {
> /* need to split node */
> unsigned long *new;
>
> --
> 2.7.4
>
--
With Best Regards,
Andy Shevchenko
