Le 02/05/2021 à 00:50, Khaled ROMDHANI a écrit :
Fix the warning: variable 'zone' is used
uninitialized whenever '?:' condition is true.
Fix that by preventing the code to reach
the last assertion. If the variable 'mirror'
is invalid, the assertion fails and we return
immediately.
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Signed-off-by: Khaled ROMDHANI <khaledromdhani216@xxxxxxxxx>
---
fs/btrfs/zoned.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 8250ab3f0868..23da9d8dc184 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -145,7 +145,7 @@ static inline u32 sb_zone_number(int shift, int mirror)
case 2: zone = 1ULL << (BTRFS_SB_LOG_SECOND_SHIFT - shift); break;
default:
ASSERT((u32)mirror < 3);
- break;
+ return 0;
}
ASSERT(zone <= U32_MAX);
base-commit: b5c294aac8a6164ddf38bfbdd1776091b4a1eeba
Hi,
just a few comments.
If I understand correctly, what you try to do is to silence a compiler
warning if no case branch is taken.
First, all your proposals are based on the previous one.
I find it hard to follow because we don't easily see what are the
differences since the beginning.
The "base-commit" at the bottom of your mail, is related to your own
local tree, I guess. It can't be used by any-one.
My understanding it that a patch, should it be v2, v3..., must apply to
the current tree. (In my case, it is the latest linux-next)
This is not the case here and you have to apply each step to see the
final result.
Should this version be fine, a maintainer wouldn't be able to apply it
as-is.
You also try to take into account previous comments to check for
incorrect negative values for minor and catch (the can't happen today)
cases, should BTRFS_SUPER_MIRROR_MAX change and this function remain the
same.
So, why hard-coding '3'?
The reason of magic numbers are hard to remember. You should avoid them
or add a comment about it.
My own personal variation would be something like the code below (untested).
Hope this helps.
CJ
diff --git a/fs/btrfs/zoned.c b/fs/btrfs/zoned.c
index 70b23a0d03b1..75fe5f001d8b 100644
--- a/fs/btrfs/zoned.c
+++ b/fs/btrfs/zoned.c
@@ -138,11 +138,14 @@ static inline u32 sb_zone_number(int shift, int
mirror)
{
u64 zone;
- ASSERT(mirror < BTRFS_SUPER_MIRROR_MAX);
+ ASSERT(mirror >= 0 && mirror < BTRFS_SUPER_MIRROR_MAX);
switch (mirror) {
case 0: zone = 0; break;
case 1: zone = 1ULL << (BTRFS_SB_LOG_FIRST_SHIFT - shift); break;
case 2: zone = 1ULL << (BTRFS_SB_LOG_SECOND_SHIFT - shift); break;
+ default:
+ ASSERT(! "mirror < BTRFS_SUPER_MIRROR_MAX but not handled above.");
+ return 0;
}
ASSERT(zone <= U32_MAX);
