From: "Zeng, Star" <star.zeng@intel.com>
To: Laszlo Ersek <lersek@redhat.com>,
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: Re: [PATCH 5/5] MdeModulePkg/PartitionDxe: remove always false comparison
Date: Tue, 12 Sep 2017 08:50:35 +0000 [thread overview]
Message-ID: <0C09AFA07DD0434D9E2A0C6AEB0483103B9400D6@shsmsx102.ccr.corp.intel.com> (raw)
In-Reply-To: <20170910001304.8628-6-lersek@redhat.com>
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
next prev parent reply other threads:[~2017-09-12 8:47 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-10 0:12 [PATCH 0/5] MdeModulePkg: UDF fixes and cleanups Laszlo Ersek
2017-09-10 0:13 ` [PATCH 1/5] MdeModulePkg/UdfDxe: ASSERT() valid ReadFileInfo Flags for INLINE_DATA req Laszlo Ersek
2017-09-10 0:13 ` [PATCH 2/5] MdeModulePkg/UdfDxe: don't return unset Status if INLINE_DATA req succeeds Laszlo Ersek
2017-09-12 9:06 ` Zeng, Star
2017-09-10 0:13 ` [PATCH 3/5] MdeModulePkg/UdfDxe: replace zero-init of local variables with ZeroMem() Laszlo Ersek
2017-09-12 8:55 ` Zeng, Star
2017-09-12 9:38 ` Ni, Ruiyu
2017-09-12 9:57 ` Laszlo Ersek
2017-09-12 10:02 ` Zeng, Star
2017-09-12 9:55 ` Laszlo Ersek
2017-09-10 0:13 ` [PATCH 4/5] MdeModulePkg/PartitionDxe: don't divide 64-bit values with C operators Laszlo Ersek
2017-09-12 5:41 ` Bi, Dandan
2017-09-12 7:58 ` Laszlo Ersek
2017-09-12 8:28 ` Ni, Ruiyu
2017-09-12 8:46 ` Zeng, Star
2017-09-10 0:13 ` [PATCH 5/5] MdeModulePkg/PartitionDxe: remove always false comparison Laszlo Ersek
2017-09-12 8:50 ` Zeng, Star [this message]
2017-09-10 4:24 ` [PATCH 0/5] MdeModulePkg: UDF fixes and cleanups Shi, Steven
2017-09-10 8:38 ` Laszlo Ersek
2017-09-10 13:52 ` Laszlo Ersek
2017-09-10 14:27 ` Shi, Steven
2017-09-10 15:51 ` Paulo Alcantara
2017-09-11 6:58 ` Laszlo Ersek
2017-09-11 13:55 ` Paulo Alcantara
2017-09-11 13:07 ` Shi, Steven
2017-09-11 13:26 ` Ni, Ruiyu
2017-09-11 13:26 ` Laszlo Ersek
2017-09-11 13:52 ` Paulo Alcantara
2017-09-11 14:00 ` Shi, Steven
2017-09-10 15:05 ` Paulo Alcantara
2017-09-11 11:58 ` Ard Biesheuvel
2017-09-12 10:14 ` Laszlo Ersek
2017-09-12 15:38 ` Ard Biesheuvel
2017-09-12 21:29 ` Laszlo Ersek
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