| Message ID | 20240911142759.20989-3-richard.weiyang@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | refine mas_mab_cp() | expand |
* Wei Yang <richard.weiyang@gmail.com> [240911 10:29]: > When we break the loop after assigning a pivot, the index i/j is not > changed. Then the following code assign pivot, which means we do the > assignment with same i/j by mas_safe_pivot. > > Since the loop condition is (i < piv_end), from which we can get i is > less than mt_pivots[mt]. It implies mas_safe_pivot() return pivot[i] > which is the same value we get in loop. > > Now we can conclude it does a redundant assignment on a pivot of 0. > Let's just go to complete to avoid it. > > Signed-off-by: Wei Yang <richard.weiyang@gmail.com> Reviewed-by: Liam R. Howlett <Liam.Howlett@Oracle.com> > --- > lib/maple_tree.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/lib/maple_tree.c b/lib/maple_tree.c > index 6fd62b7ef240..f7bb3f686548 100644 > --- a/lib/maple_tree.c > +++ b/lib/maple_tree.c > @@ -1942,7 +1942,7 @@ static inline void mas_mab_cp(struct ma_state *mas, unsigned char mas_start, > for (; i < piv_end; i++, j++) { > b_node->pivot[j] = pivots[i]; > if (unlikely(!b_node->pivot[j])) > - break; > + goto complete; > > if (unlikely(mas->max == b_node->pivot[j])) > goto complete; > -- > 2.34.1 >
diff --git a/lib/maple_tree.c b/lib/maple_tree.c index 6fd62b7ef240..f7bb3f686548 100644 --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -1942,7 +1942,7 @@ static inline void mas_mab_cp(struct ma_state *mas, unsigned char mas_start, for (; i < piv_end; i++, j++) { b_node->pivot[j] = pivots[i]; if (unlikely(!b_node->pivot[j])) - break; + goto complete; if (unlikely(mas->max == b_node->pivot[j])) goto complete;
When we break the loop after assigning a pivot, the index i/j is not changed. Then the following code assign pivot, which means we do the assignment with same i/j by mas_safe_pivot. Since the loop condition is (i < piv_end), from which we can get i is less than mt_pivots[mt]. It implies mas_safe_pivot() return pivot[i] which is the same value we get in loop. Now we can conclude it does a redundant assignment on a pivot of 0. Let's just go to complete to avoid it. Signed-off-by: Wei Yang <richard.weiyang@gmail.com> --- lib/maple_tree.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)