linux-kernel - Re: [PATCH 1/2] elf: simpler check for -EEXIST

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Message-ID: <20190315160517.GA2135@avx2>
Date:   Fri, 15 Mar 2019 19:05:17 +0300
From:   Alexey Dobriyan <adobriyan@...il.com>
To:     Tetsuo Handa <penguin-kernel@...ove.sakura.ne.jp>
Cc:     akpm@...ux-foundation.org, linux-kernel@...r.kernel.org,
        Michal Hocko <mhocko@...nel.org>
Subject: Re: [PATCH 1/2] elf: simpler check for -EEXIST

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@...il.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);
> >  
> > 
>