Re: [PATCH net-next 2/2] bonding: combine netlink and console error messages

[Jonathan Toppins]

On 8/8/21 6:02 AM, Joe Perches wrote:
> On Sat, 2021-08-07 at 17:54 -0400, Jonathan Toppins wrote:
> > On 8/6/21 11:52 PM, Joe Perches wrote:
> > > On Fri, 2021-08-06 at 23:30 -0400, Jonathan Toppins wrote:
> > > > There seems to be no reason to have different error messages between
> > > > netlink and printk. It also cleans up the function slightly.
> > > []
> > > > diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
> > > []
> > > > +#define BOND_NL_ERR(bond_dev, extack, errmsg) do {		\
> > > > +	NL_SET_ERR_MSG(extack, errmsg);				\
> > > > +	netdev_err(bond_dev, "Error: " errmsg "\n");		\
> > > > +} while (0)
> > > > +
> > > > +#define SLAVE_NL_ERR(bond_dev, slave_dev, extack, errmsg) do {	\
> > > > +	NL_SET_ERR_MSG(extack, errmsg);				\
> > > > +	slave_err(bond_dev, slave_dev, "Error: " errmsg "\n");	\
> > > > +} while (0)
> > >
> > > If you are doing this, it's probably smaller object code to use
> > > 	"%s", errmsg
> > > as the errmsg string can be reused
> > >
> > > #define BOND_NL_ERR(bond_dev, extack, errmsg)			\
> > > do {								\
> > > 	NL_SET_ERR_MSG(extack, errmsg);				\
> > > 	netdev_err(bond_dev, "Error: %s\n", errmsg);		\
> > > } while (0)
> > >
> > > #define SLAVE_NL_ERR(bond_dev, slave_dev, extack, errmsg)	\
> > > do {								\
> > > 	NL_SET_ERR_MSG(extack, errmsg);				\
> > > 	slave_err(bond_dev, slave_dev, "Error: %s\n", errmsg);	\
> > > } while (0)
> >
> > I like the thought and would agree if not for how NL_SET_ERR_MSG is
> > coded. Unfortunately it does not appear as though doing the above change
> > actually generates smaller object code. Maybe I have incorrectly
> > interpreted something?
>
> No, it's because you are compiling allyesconfig or equivalent.
> Try defconfig with bonding.

$ git clean -dxf
$ git log -1 -p
commit 8985f8d3fa38bca5f5384f9210ed735d58fd94f2 (HEAD -> 
upstream-bonding-cleanup)
Author: Jonathan Toppins <jtoppins@xxxxxxxxxx>
Date:   Sun Aug 8 21:45:14 2021 -0400

    object code optimization

diff --git a/drivers/net/bonding/bond_main.c 
b/drivers/net/bonding/bond_main.c
index 46b95175690b..e2903ae7cdab 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1714,12 +1714,12 @@ void bond_lower_state_changed(struct slave *slave)

 #define BOND_NL_ERR(bond_dev, extack, errmsg) do {             \
        NL_SET_ERR_MSG(extack, errmsg);                         \
-       netdev_err(bond_dev, "Error: " errmsg "\n");            \
+       netdev_err(bond_dev, "Error: %s\n", errmsg);            \
 } while (0)

 #define SLAVE_NL_ERR(bond_dev, slave_dev, extack, errmsg) do { \
        NL_SET_ERR_MSG(extack, errmsg);                         \
-       slave_err(bond_dev, slave_dev, "Error: " errmsg "\n");  \
+       slave_err(bond_dev, slave_dev, "Error: %s\n", errmsg);  \
 } while (0)

 /* enslave device <slave> to bond device <master> */
$ git log --oneline -2
8985f8d3fa38 (HEAD -> upstream-bonding-cleanup) object code optimization
e326bf8fd30f bonding: combine netlink and console error messages
$ make defconfig
  HOSTCC  scripts/basic/fixdep
[...]
*** Default configuration is based on 'x86_64_defconfig'
#
# configuration written to .config
#
$ grep "BONDING" .config
# CONFIG_BONDING is not set
$ make menuconfig
  UPD     scripts/kconfig/mconf-cfg
[...]
configuration written to .config

*** End of the configuration.
*** Execute 'make' to start the build or try 'make help'.

$ grep "BONDING" .config
CONFIG_BONDING=m
$ git rebase -i --exec "make drivers/net/bonding/bond_main.o; ls -l 
drivers/net/bonding/bond_main.o" HEAD^^
Executing: make drivers/net/bonding/bond_main.o; ls -l 
drivers/net/bonding/bond_main.o
  SYNC    include/config/auto.conf.cmd
[...]
  CC      /home/jtoppins/projects/linux-rhel7/tools/objtool/librbtree.o
  LD      /home/jtoppins/projects/linux-rhel7/tools/objtool/objtool-in.o
  LINK    /home/jtoppins/projects/linux-rhel7/tools/objtool/objtool
  CC [M]  drivers/net/bonding/bond_main.o
-rw-r--r--. 1 jtoppins jtoppins 131800 Aug  8 21:47 
drivers/net/bonding/bond_main.o
Executing: make drivers/net/bonding/bond_main.o; ls -l 
drivers/net/bonding/bond_main.o
  CALL    scripts/checksyscalls.sh
  CALL    scripts/atomic/check-atomics.sh
  DESCEND objtool
  CC [M]  drivers/net/bonding/bond_main.o
-rw-r--r--. 1 jtoppins jtoppins 131928 Aug  8 21:47 
drivers/net/bonding/bond_main.o
Successfully rebased and updated refs/heads/upstream-bonding-cleanup.
$ gcc --version
gcc (GCC) 8.4.1 20200928 (Red Hat 8.4.1-1)
Copyright (C) 2018 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

-Jon