Messages in this thread | | | Date | Fri, 20 Apr 2018 22:46:28 +0300 | From | Alexey Dobriyan <> | Subject | Re: [PATCH 4/5] proc: simpler iterations for /proc/*/cmdline |
| |
On Thu, Apr 19, 2018 at 05:15:20PM -0700, Andrew Morton wrote: > On Wed, 21 Feb 2018 22:30:09 +0300 Alexey Dobriyan <adobriyan@gmail.com> wrote: > > > "rv" variable is used both as a counter of bytes transferred and > > an error value holder but it can be reduced solely to error values > > if original start of userspace buffer is stashed and used at the very > > end. > > > > ... > > > > --- a/fs/proc/base.c > > +++ b/fs/proc/base.c > > > > ... > > > > @@ -371,12 +365,16 @@ static ssize_t proc_pid_cmdline_read(struct file *file, char __user *buf, > > } > > } > > > > +end: > > + free_page((unsigned long)page); > > + mmput(mm); > > + *pos += buf - buf0; > > + return buf - buf0; > > + > > out_free_page: > > free_page((unsigned long)page); > > out_mmput: > > mmput(mm); > > - if (rv > 0) > > - *pos += rv; > > return rv; > > } > > (scratches head). Why not do this? > > --- a/fs/proc/base.c~proc-simpler-iterations-for-proc-cmdline-fix > +++ a/fs/proc/base.c > @@ -363,11 +363,8 @@ static ssize_t proc_pid_cmdline_read(str > } > > end: > - free_page((unsigned long)page); > - mmput(mm); > *pos += buf - buf0; > - return buf - buf0; > - > + rv = buf - buf0; > out_free_page: > free_page((unsigned long)page); > out_mmput: > > (and maybe rv should be ssize_t)
It should as cmdline area can be set to arbitrary values.
I hate ssize_t and it's bloat.
$ ./scripts/bloat-o-meter ../vmlinux-000 ../obj/vmlinux add/remove: 0/0 grow/shrink: 1/0 up/down: 11/0 (11) Function old new delta proc_pid_cmdline_read 867 878 +11
| |