Messages in this thread Patch in this message | | | Date | Thu, 19 Apr 2018 17:15:20 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH 4/5] proc: simpler iterations for /proc/*/cmdline |
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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)
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