From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Smalley Subject: Re: [PATCH 2/3] proc: Update get proc_pid_cmdline() to use mm.h helpers Date: Fri, 13 Dec 2013 09:23:49 -0500 Message-ID: <52AB1875.2090207@tycho.nsa.gov> References: <1386018639-18916-1-git-send-email-wroberts@tresys.com> <1386018639-18916-3-git-send-email-wroberts@tresys.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1386018639-18916-3-git-send-email-wroberts@tresys.com> Sender: owner-linux-mm@kvack.org To: William Roberts , linux-audit@redhat.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, rgb@redhat.com, viro@zeniv.linux.org.uk Cc: William Roberts List-Id: linux-audit@redhat.com On 12/02/2013 04:10 PM, William Roberts wrote: > Re-factor proc_pid_cmdline() to use get_cmdline_length() and > copy_cmdline() helpers from mm.h > > Signed-off-by: William Roberts > --- > fs/proc/base.c | 35 ++++++++++------------------------- > 1 file changed, 10 insertions(+), 25 deletions(-) > > diff --git a/fs/proc/base.c b/fs/proc/base.c > index 03c8d74..fb4eda5 100644 > --- a/fs/proc/base.c > +++ b/fs/proc/base.c > @@ -203,37 +203,22 @@ static int proc_root_link(struct dentry *dentry, struct path *path) > static int proc_pid_cmdline(struct task_struct *task, char * buffer) > { > int res = 0; > - unsigned int len; > + unsigned int len = 0; Why? You set len below before first use, so this is redundant. > struct mm_struct *mm = get_task_mm(task); > if (!mm) > - goto out; > - if (!mm->arg_end) > - goto out_mm; /* Shh! No looking before we're done */ > + return 0; Equivalent to goto out in the original code, so why change it? Don't make unnecessary changes. Also, I think the get_task_mm() ought to move into the helper (or all of proc_pid_cmdline() should just become the helper). In what situation will you not be calling get_task_mm() and mmput() around every call to the helper? > > - len = mm->arg_end - mm->arg_start; > - > + len = get_cmdline_length(mm); > + if (!len) > + goto mm_out; Could be moved into the helper. Not sure how the inline function helps readability or maintainability. > + > + /*The caller of this allocates a page */ > if (len > PAGE_SIZE) > len = PAGE_SIZE; If the capping of len is handled by the caller, then pass an int to your helper rather than an unsigned int to avoid problems later with access_process_vm(). > -out_mm: > + > + res = copy_cmdline(task, mm, buffer, len); > +mm_out: > mmput(mm); Odd style. If there is only one exit path, just call it out; if there are two, keep them as out_mm and out. > -out: > return res; > } > > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org