2020-12-17 05:31:30

by Adrian Huang

Subject: [PATCH 1/1] x86/mm: Refine mmap syscall implementation

From: Adrian Huang <[email protected]>

It is unnecessary to use the local variable 'error' in the mmap
syscall implementation function, so use the return statement
instead of it.

Signed-off-by: Adrian Huang <[email protected]>
---
arch/x86/kernel/sys_x86_64.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/sys_x86_64.c b/arch/x86/kernel/sys_x86_64.c
index 504fa5425bce..660b78827638 100644
--- a/arch/x86/kernel/sys_x86_64.c
+++ b/arch/x86/kernel/sys_x86_64.c
@@ -90,14 +90,10 @@ SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,
unsigned long, prot, unsigned long, flags,
unsigned long, fd, unsigned long, off)
{
- long error;
- error = -EINVAL;
if (off & ~PAGE_MASK)
- goto out;
+ return -EINVAL;

- error = ksys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT);
-out:
- return error;
+ return ksys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT);
}

static void find_start_end(unsigned long addr, unsigned long flags,
--
2.17.1

2020-12-22 14:55:15

by Christoph Hellwig

Subject: Re: [PATCH 1/1] x86/mm: Refine mmap syscall implementation

On Thu, Dec 17, 2020 at 01:26:48PM +0800, Adrian Huang wrote:
> From: Adrian Huang <[email protected]>
>
> It is unnecessary to use the local variable 'error' in the mmap
> syscall implementation function, so use the return statement
> instead of it.

I'm normally not a fan of standalone cleanup patches, but this one
actually improves the function a lot, so:

Reviewed-by: Christoph Hellwig <[email protected]>

2021-01-05 18:31:12

by tip-bot2 for Alexey Makhalov

Subject: [tip: x86/cleanups] x86/mm: Refine mmap syscall implementation

The following commit has been merged into the x86/cleanups branch of tip:

Commit-ID: 91a8f6cb06b33adc79fbf5f7381d907485767c00
Gitweb: https://git.kernel.org/tip/91a8f6cb06b33adc79fbf5f7381d907485767c00
Author: Adrian Huang <[email protected]>
AuthorDate: Thu, 17 Dec 2020 13:26:48 +08:00
Committer: Borislav Petkov <[email protected]>
CommitterDate: Tue, 05 Jan 2021 19:07:42 +01:00

x86/mm: Refine mmap syscall implementation

It is unnecessary to use the local variable 'error' in the mmap syscall
implementation function - just return -EINVAL directly and get rid of
the local variable altogether.

[ bp: Massage commit message. ]

Signed-off-by: Adrian Huang <[email protected]>
Signed-off-by: Borislav Petkov <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
---
arch/x86/kernel/sys_x86_64.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/sys_x86_64.c b/arch/x86/kernel/sys_x86_64.c
index 504fa54..660b788 100644
--- a/arch/x86/kernel/sys_x86_64.c
+++ b/arch/x86/kernel/sys_x86_64.c
@@ -90,14 +90,10 @@ SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len,
unsigned long, prot, unsigned long, flags,
unsigned long, fd, unsigned long, off)
{
- long error;
- error = -EINVAL;
if (off & ~PAGE_MASK)
- goto out;
+ return -EINVAL;

- error = ksys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT);
-out:
- return error;
+ return ksys_mmap_pgoff(addr, len, prot, flags, fd, off >> PAGE_SHIFT);
}

static void find_start_end(unsigned long addr, unsigned long flags,