Re: [PATCH fs/proc/bootconfig] remove redundant comments from /proc/bootconfig

[Paul E. McKenney]

On Fri, Apr 05, 2024 at 11:57:45AM +0900, Masami Hiramatsu wrote:
> On Fri, 5 Apr 2024 10:23:24 +0900
> Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx> wrote:
> 
> > On Thu, 4 Apr 2024 10:43:14 -0700
> > "Paul E. McKenney" <paulmck@xxxxxxxxxx> wrote:
> > 
> > > On Thu, Apr 04, 2024 at 08:55:22AM +0900, Masami Hiramatsu wrote:
> > > > On Wed, 3 Apr 2024 12:16:28 -0700
> > > > "Paul E. McKenney" <paulmck@xxxxxxxxxx> wrote:
> > > > 
> > > > > commit 717c7c894d4b ("fs/proc: Add boot loader arguments as comment to
> > > > > /proc/bootconfig") adds bootloader argument comments into /proc/bootconfig.
> > > > > 
> > > > > /proc/bootconfig shows boot_command_line[] multiple times following
> > > > > every xbc key value pair, that's duplicated and not necessary.
> > > > > Remove redundant ones.
> > > > > 
> > > > > Output before and after the fix is like:
> > > > > key1 = value1
> > > > > *bootloader argument comments*
> > > > > key2 = value2
> > > > > *bootloader argument comments*
> > > > > key3 = value3
> > > > > *bootloader argument comments*
> > > > > ...
> > > > > 
> > > > > key1 = value1
> > > > > key2 = value2
> > > > > key3 = value3
> > > > > *bootloader argument comments*
> > > > > ...
> > > > > 
> > > > > Fixes: 717c7c894d4b ("fs/proc: Add boot loader arguments as comment to /proc/bootconfig")
> > > > > Signed-off-by: Zhenhua Huang <quic_zhenhuah@xxxxxxxxxxx>
> > > > > Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
> > > > > Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
> > > > > Cc: <linux-trace-kernel@xxxxxxxxxxxxxxx>
> > > > > Cc: <linux-fsdevel@xxxxxxxxxxxxxxx>
> > > > 
> > > > OOps, good catch! Let me pick it.
> > > > 
> > > > Acked-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
> > > 
> > > Thank you, and I have applied your ack and pulled this into its own
> > > bootconfig.2024.04.04a.
> > > 
> > > My guess is that you will push this via your own tree, and so I will
> > > drop my copy as soon as yours hits -next.
> > 
> > Thanks! I would like to make PR this soon as bootconfig fixes for v6.9-rc2.
> 
> Hmm I found that this always shows the command line comment in
> /proc/bootconfig even without "bootconfig" option.
> I think that is easier for user-tools but changes the behavior and
> a bit redundant.
> 
> We should skip showing this original argument comment if bootconfig is
> not initialized (no "bootconfig" in cmdline) as it is now.

So something like this folded into that patch?

------------------------------------------------------------------------

diff --git a/fs/proc/bootconfig.c b/fs/proc/bootconfig.c
index e5635a6b127b0..7d2520378f5f2 100644
--- a/fs/proc/bootconfig.c
+++ b/fs/proc/bootconfig.c
@@ -63,7 +63,7 @@ static int __init copy_xbc_key_value_list(char *dst, size_t size)
 			dst += ret;
 		}
 	}
-	if (ret >= 0 && boot_command_line[0]) {
+	if (bootconfig_is_present() && ret >= 0 && boot_command_line[0]) {
 		ret = snprintf(dst, rest(dst, end), "# Parameters from bootloader:\n# %s\n",
 			       boot_command_line);
 		if (ret > 0)
diff --git a/include/linux/bootconfig.h b/include/linux/bootconfig.h
index ca73940e26df8..ef70d1b381421 100644
--- a/include/linux/bootconfig.h
+++ b/include/linux/bootconfig.h
@@ -10,6 +10,7 @@
 #ifdef __KERNEL__
 #include <linux/kernel.h>
 #include <linux/types.h>
+int bootconfig_is_present(void);
 #else /* !__KERNEL__ */
 /*
  * NOTE: This is only for tools/bootconfig, because tools/bootconfig will
diff --git a/init/main.c b/init/main.c
index 2ca52474d0c30..720a669b1493d 100644
--- a/init/main.c
+++ b/init/main.c
@@ -1572,3 +1572,8 @@ static noinline void __init kernel_init_freeable(void)
 
 	integrity_load_keys();
 }
+
+int bootconfig_is_present(void)
+{
+	return bootconfig_found || IS_ENABLED(CONFIG_BOOT_CONFIG_FORCE);
+}

------------------------------------------------------------------------

Give or take placement of the bootconfig_is_present() function's
declaration and definition.

							Thanx, Paul

							Thanx, Paul

> Thank you,
> 
> 
> > Thank you,
> > 
> > > 
> > > 							Thanx, Paul
> > > 
> > > > Thank you!
> > > > 
> > > > > 
> > > > > diff --git a/fs/proc/bootconfig.c b/fs/proc/bootconfig.c
> > > > > index 902b326e1e560..e5635a6b127b0 100644
> > > > > --- a/fs/proc/bootconfig.c
> > > > > +++ b/fs/proc/bootconfig.c
> > > > > @@ -62,12 +62,12 @@ static int __init copy_xbc_key_value_list(char *dst, size_t size)
> > > > >  				break;
> > > > >  			dst += ret;
> > > > >  		}
> > > > > -		if (ret >= 0 && boot_command_line[0]) {
> > > > > -			ret = snprintf(dst, rest(dst, end), "# Parameters from bootloader:\n# %s\n",
> > > > > -				       boot_command_line);
> > > > > -			if (ret > 0)
> > > > > -				dst += ret;
> > > > > -		}
> > > > > +	}
> > > > > +	if (ret >= 0 && boot_command_line[0]) {
> > > > > +		ret = snprintf(dst, rest(dst, end), "# Parameters from bootloader:\n# %s\n",
> > > > > +			       boot_command_line);
> > > > > +		if (ret > 0)
> > > > > +			dst += ret;
> > > > >  	}
> > > > >  out:
> > > > >  	kfree(key);
> > > > 
> > > > 
> > > > -- 
> > > > Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
> > 
> > 
> > -- 
> > Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
> 
> 
> -- 
> Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>