[PATCH] userns: simplify map_id_range_* functions

From: Nicolas Iooss
Date: Sat Jul 25 2015 - 22:01:50 EST


Functions map_id_range_down, map_id_down and map_id_up all used the
construction:

if (...)
id = ...
else
id = ...
return id;

which can be simplified by directly returning the result of the
computations in each branch.

Moreover as the condition tested whether the "break;" in the previous
for loop was hit, it is simpler to directly compute the result and
return it.

Signed-off-by: Nicolas Iooss <nicolas.iooss_linux@xxxxxxx>
---

As I could not find any relevant entry for kernel/user_namespace.c in
MAINTAINERS, I have built the list of recipients from the git history.
Please let me know if I was expected to proceed differently to submit
this patch.

kernel/user_namespace.c | 31 +++++++------------------------
1 file changed, 7 insertions(+), 24 deletions(-)

diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index 4109f8320684..bf063dc6b8d4 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -165,15 +165,10 @@ static u32 map_id_range_down(struct uid_gid_map *map, u32 id, u32 count)
last = first + map->extent[idx].count - 1;
if (id >= first && id <= last &&
(id2 >= first && id2 <= last))
- break;
+ return (id - first) + map->extent[idx].lower_first;
}
- /* Map the id or note failure */
- if (idx < extents)
- id = (id - first) + map->extent[idx].lower_first;
- else
- id = (u32) -1;
-
- return id;
+ /* Note failure */
+ return (u32) -1;
}

static u32 map_id_down(struct uid_gid_map *map, u32 id)
@@ -188,15 +183,9 @@ static u32 map_id_down(struct uid_gid_map *map, u32 id)
first = map->extent[idx].first;
last = first + map->extent[idx].count - 1;
if (id >= first && id <= last)
- break;
+ return (id - first) + map->extent[idx].lower_first;
}
- /* Map the id or note failure */
- if (idx < extents)
- id = (id - first) + map->extent[idx].lower_first;
- else
- id = (u32) -1;
-
- return id;
+ return (u32) -1;
}

static u32 map_id_up(struct uid_gid_map *map, u32 id)
@@ -211,15 +200,9 @@ static u32 map_id_up(struct uid_gid_map *map, u32 id)
first = map->extent[idx].lower_first;
last = first + map->extent[idx].count - 1;
if (id >= first && id <= last)
- break;
+ return (id - first) + map->extent[idx].first;
}
- /* Map the id or note failure */
- if (idx < extents)
- id = (id - first) + map->extent[idx].first;
- else
- id = (u32) -1;
-
- return id;
+ return (u32) -1;
}

/**
--
2.4.6

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