Reviewed-by: Star Zeng <star.zeng@intel.com>
-----Original Message-----
From: Laszlo Ersek [mailto:lersek@redhat.com]
Sent: Sunday, September 10, 2017 8:13 AM
To: edk2-devel-01 <edk2-devel@lists.01.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>; Dong, Eric <eric.dong@intel.com>; Paulo Alcantara <pcacjr@zytor.com>; Ni, Ruiyu <ruiyu.ni@intel.com>; Zeng, Star <star.zeng@intel.com>
Subject: [PATCH 5/5] MdeModulePkg/PartitionDxe: remove always false comparison
In the expression
(RemainderByMediaBlockSize != 0 ||
Media->BlockSize > UDF_LOGICAL_SECTOR_SIZE)
the second expression is only evaluated if the first expression is false.
If the first expression is false, i.e.,
RemainderByMediaBlockSize == 0
then UDF_LOGICAL_SECTOR_SIZE is a whole multiple of "Media->BlockSize", which implies
UDF_LOGICAL_SECTOR_SIZE >= Media->BlockSize.
Therefore whenever
Media->BlockSize > UDF_LOGICAL_SECTOR_SIZE
is evaluated, it is false.
The expression
((expression) || FALSE)
is equivalent to
(expression).
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Paulo Alcantara <pcacjr@zytor.com>
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
---
MdeModulePkg/Universal/Disk/PartitionDxe/Udf.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/MdeModulePkg/Universal/Disk/PartitionDxe/Udf.c b/MdeModulePkg/Universal/Disk/PartitionDxe/Udf.c
index c491ef25f47e..3347b48421a8 100644
--- a/MdeModulePkg/Universal/Disk/PartitionDxe/Udf.c
+++ b/MdeModulePkg/Universal/Disk/PartitionDxe/Udf.c
@@ -252,12 +252,11 @@ PartitionInstallUdfChildHandles (
DivU64x32Remainder (
UDF_LOGICAL_SECTOR_SIZE, // Dividend
Media->BlockSize, // Divisor
&RemainderByMediaBlockSize // Remainder
);
- if (RemainderByMediaBlockSize != 0 ||
- Media->BlockSize > UDF_LOGICAL_SECTOR_SIZE) {
+ if (RemainderByMediaBlockSize != 0) {
return EFI_NOT_FOUND;
}
DevicePathNode = DevicePath;
while (!IsDevicePathEnd (DevicePathNode)) {
--
2.14.1.3.gb7cf6e02401b
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