* [PATCH 1/2] elf: simpler check for -EEXIST
@ 2019-03-14 20:42 Alexey Dobriyan
2019-03-14 22:02 ` Tetsuo Handa
0 siblings, 1 reply; 4+ messages in thread
From: Alexey Dobriyan @ 2019-03-14 20:42 UTC (permalink / raw)
To: akpm; +Cc: linux-kernel, penguin-kernel
PTR_ERR((void *)map_addr) == -EEXIST
is a very complicated way of doing the obvious.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---
fs/binfmt_elf.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -375,8 +375,7 @@ static unsigned long elf_map(struct file *filep, unsigned long addr,
} else
map_addr = vm_mmap(filep, addr, size, prot, type, off);
- if ((type & MAP_FIXED_NOREPLACE) &&
- PTR_ERR((void *)map_addr) == -EEXIST)
+ if ((type & MAP_FIXED_NOREPLACE) && map_addr == -EEXIST)
pr_info("%d (%s): Uhuuh, elf segment at %px requested but the memory is mapped already\n",
task_pid_nr(current), current->comm, (void *)addr);
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH 1/2] elf: simpler check for -EEXIST
2019-03-14 20:42 [PATCH 1/2] elf: simpler check for -EEXIST Alexey Dobriyan
@ 2019-03-14 22:02 ` Tetsuo Handa
2019-03-15 16:05 ` Alexey Dobriyan
0 siblings, 1 reply; 4+ messages in thread
From: Tetsuo Handa @ 2019-03-14 22:02 UTC (permalink / raw)
To: Alexey Dobriyan, akpm; +Cc: linux-kernel, Michal Hocko
On 2019/03/15 5:42, Alexey Dobriyan wrote:
> PTR_ERR((void *)map_addr) == -EEXIST
>
> is a very complicated way of doing the obvious.
Michal suggested me to explicitly use PTR_ERR() for documentation purpose in
a reply mail to https://lkml.kernel.org/r/20180418115546.GZ17484@dhcp22.suse.cz .
>
> Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
> ---
>
> fs/binfmt_elf.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> --- a/fs/binfmt_elf.c
> +++ b/fs/binfmt_elf.c
> @@ -375,8 +375,7 @@ static unsigned long elf_map(struct file *filep, unsigned long addr,
> } else
> map_addr = vm_mmap(filep, addr, size, prot, type, off);
>
> - if ((type & MAP_FIXED_NOREPLACE) &&
> - PTR_ERR((void *)map_addr) == -EEXIST)
> + if ((type & MAP_FIXED_NOREPLACE) && map_addr == -EEXIST)
> pr_info("%d (%s): Uhuuh, elf segment at %px requested but the memory is mapped already\n",
> task_pid_nr(current), current->comm, (void *)addr);
>
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH 1/2] elf: simpler check for -EEXIST
2019-03-14 22:02 ` Tetsuo Handa
@ 2019-03-15 16:05 ` Alexey Dobriyan
2019-03-16 8:31 ` Michal Hocko
0 siblings, 1 reply; 4+ messages in thread
From: Alexey Dobriyan @ 2019-03-15 16:05 UTC (permalink / raw)
To: Tetsuo Handa; +Cc: akpm, linux-kernel, Michal Hocko
On Fri, Mar 15, 2019 at 07:02:23AM +0900, Tetsuo Handa wrote:
> On 2019/03/15 5:42, Alexey Dobriyan wrote:
> > PTR_ERR((void *)map_addr) == -EEXIST
> >
> > is a very complicated way of doing the obvious.
>
> Michal suggested me to explicitly use PTR_ERR()
without any explanation why...
I wonder what documentation does this line need?
map_addr == -EEXIST
> for documentation purpose in
> a reply mail to https://lkml.kernel.org/r/20180418115546.GZ17484@dhcp22.suse.cz .
>
> >
> > Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
> > ---
> >
> > fs/binfmt_elf.c | 3 +--
> > 1 file changed, 1 insertion(+), 2 deletions(-)
> >
> > --- a/fs/binfmt_elf.c
> > +++ b/fs/binfmt_elf.c
> > @@ -375,8 +375,7 @@ static unsigned long elf_map(struct file *filep, unsigned long addr,
> > } else
> > map_addr = vm_mmap(filep, addr, size, prot, type, off);
> >
> > - if ((type & MAP_FIXED_NOREPLACE) &&
> > - PTR_ERR((void *)map_addr) == -EEXIST)
> > + if ((type & MAP_FIXED_NOREPLACE) && map_addr == -EEXIST)
> > pr_info("%d (%s): Uhuuh, elf segment at %px requested but the memory is mapped already\n",
> > task_pid_nr(current), current->comm, (void *)addr);
> >
> >
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH 1/2] elf: simpler check for -EEXIST
2019-03-15 16:05 ` Alexey Dobriyan
@ 2019-03-16 8:31 ` Michal Hocko
0 siblings, 0 replies; 4+ messages in thread
From: Michal Hocko @ 2019-03-16 8:31 UTC (permalink / raw)
To: Alexey Dobriyan; +Cc: Tetsuo Handa, akpm, linux-kernel
On Fri 15-03-19 19:05:17, Alexey Dobriyan wrote:
> On Fri, Mar 15, 2019 at 07:02:23AM +0900, Tetsuo Handa wrote:
> > On 2019/03/15 5:42, Alexey Dobriyan wrote:
> > > PTR_ERR((void *)map_addr) == -EEXIST
> > >
> > > is a very complicated way of doing the obvious.
> >
> > Michal suggested me to explicitly use PTR_ERR()
>
> without any explanation why...
The return value is ERR_PTR. This code uses unsigned long which is OK
but I thought it is better to call out the return value convention
explicitly. It is not like I would argue about that though.
--
Michal Hocko
SUSE Labs
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2019-03-16 8:31 UTC | newest]
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2019-03-14 20:42 [PATCH 1/2] elf: simpler check for -EEXIST Alexey Dobriyan
2019-03-14 22:02 ` Tetsuo Handa
2019-03-15 16:05 ` Alexey Dobriyan
2019-03-16 8:31 ` Michal Hocko
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