ext2/ext3:useless code for return value
Subsystems (2)
PATCH 1/1 ext2/ext3:useless code for return value
When rsv is the right hand side of goal, we should return NULL, because now rsv's prev is NULL, or we return rsv.
--- fs/ext2/balloc.c | 6 +----- fs/ext3/balloc.c | 6 +----- 2 files changed, 2 insertions(+), 10 deletions(-)
fs/ext2/balloc.c +0 -0
@@ -323,11 +323,7 @@ search_reserve_window(struct rb_root *root,
ext2_fsblk_t goal)
* side of the interval containing the goal. If it's the RHS,
* we need to back up one.
*/
- if (rsv->rsv_start > goal) {
- n = rb_prev(&rsv->rsv_node);
- rsv = rb_entry(n, struct ext2_reserve_window_node, rsv_node);
- }
- return rsv;
+ return (rsv->rsv_start < goal) ? rsv : NULL;
}
/*
fs/ext3/balloc.c +0 -0
@@ -310,11 +310,7 @@ search_reserve_window(struct rb_root *root,
ext3_fsblk_t goal)
* side of the interval containing the goal. If it's the RHS,
* we need to back up one.
*/
- if (rsv->rsv_start > goal) {
- n = rb_prev(&rsv->rsv_node);
- rsv = rb_entry(n, struct ext3_reserve_window_node, rsv_node);
- }
- return rsv;
+ return (rsv->rsv_start < goal) ? rsv : NULL;
}
/**
Signature · 10 lines
1.6.6 -- Peter Pan(潘卫平) Red Flag Software Co.,Ltd -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
Quoted 15 lines
When rsv is the right hand side of goal, we should return NULL, because now rsv's prev is NULL, or we return rsv.
Signed-off-by Peter Pan(潘卫平) <[email protected]>--- fs/ext2/balloc.c | 6 +----- fs/ext3/balloc.c | 6 +----- 2 files changed, 2 insertions(+), 10 deletions(-)fs/ext2/balloc.c +0
-0
fs/ext2/balloc.c search_reserve_window(struct rb_root *root, · line 327
Quoted 10 lines
fs/ext2/balloc.c +1
-5@@ -323,11 +323,7 @@ search_reserve_window(struct rb_root *root,ext2_fsblk_t goal) * side of the interval containing the goal. If it's the RHS, * we need to back up one. */ -if (rsv->rsv_start > goal) { - n =rb_prev (&rsv->rsv_node); - rsv = rb_entry(n, struct ext2_reserve_window_node, rsv_node); - } -return rsv; +return (rsv->rsv_start < goal) ? rsv :NULL ;
Hmm, I'm not sure I understand your reasoning. Suppose we have an RB-tree
with two intervals 0-10, 20-30. Interval 0-10 is in the root. Now we search for goal 15. In the root we go to right because 10<15, in the next node we go to left because 15 < 20. Then the loop terminates. Now your code would return NULL but previous code would return rb_prev of interval 20-30 which is 0-10. And that is what we want as far as I understand what we expect from the function...
Honza
Signature · 6 lines
Jan Kara <[email protected]> SuSE CR Labs -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
Quoted 33 lines · Jan Kara
Quoted 15 lines
When rsv is the right hand side of goal, we should return NULL, because now rsv's prev is NULL, or we return rsv.
Signed-off-by Peter Pan(潘卫平)<[email protected]>--- fs/ext2/balloc.c | 6 +----- fs/ext3/balloc.c | 6 +----- 2 files changed, 2 insertions(+), 10 deletions(-)fs/ext2/balloc.c +0
-0fs/ext2/balloc.c search_reserve_window(struct rb_root *root, · line 327
Quoted 10 lines
fs/ext2/balloc.c +1
-5@@ -323,11 +323,7 @@ search_reserve_window(struct rb_root *root,ext2_fsblk_t goal) * side of the interval containing the goal. If it's the RHS, * we need to back up one. */ -if (rsv->rsv_start> goal) { - n =rb_prev (&rsv->rsv_node); - rsv = rb_entry(n, struct ext2_reserve_window_node, rsv_node); - } -return rsv; +return (rsv->rsv_start< goal) ? rsv :NULL ;Hmm, I'm not sure I understand your reasoning. Suppose we have an RB-tree
with two intervals 0-10, 20-30. Interval 0-10 is in the root. Now we search for goal 15. In the root we go to right because 10<15, in the next node we go to left because 15< 20. Then the loop terminates. Now your code would return NULL but previous code would returnrb_prevof interval 20-30 which is 0-10. And that is what we want as far as I understand what we expect from the function...
Quoted 1 line
Honza
You got the point!
Many thanks.
Regards
Signature · 2 lines
Peter Pan Red Flag Software Co.,Ltd