kernel-ark/fs/dlm
Johannes Berg 053c095a82 netlink: make nlmsg_end() and genlmsg_end() void
Contrary to common expectations for an "int" return, these functions
return only a positive value -- if used correctly they cannot even
return 0 because the message header will necessarily be in the skb.

This makes the very common pattern of

  if (genlmsg_end(...) < 0) { ... }

be a whole bunch of dead code. Many places also simply do

  return nlmsg_end(...);

and the caller is expected to deal with it.

This also commonly (at least for me) causes errors, because it is very
common to write

  if (my_function(...))
    /* error condition */

and if my_function() does "return nlmsg_end()" this is of course wrong.

Additionally, there's not a single place in the kernel that actually
needs the message length returned, and if anyone needs it later then
it'll be very easy to just use skb->len there.

Remove this, and make the functions void. This removes a bunch of dead
code as described above. The patch adds lines because I did

-	return nlmsg_end(...);
+	nlmsg_end(...);
+	return 0;

I could have preserved all the function's return values by returning
skb->len, but instead I've audited all the places calling the affected
functions and found that none cared. A few places actually compared
the return value with <= 0 in dump functionality, but that could just
be changed to < 0 with no change in behaviour, so I opted for the more
efficient version.

One instance of the error I've made numerous times now is also present
in net/phonet/pn_netlink.c in the route_dumpit() function - it didn't
check for <0 or <=0 and thus broke out of the loop every single time.
I've preserved this since it will (I think) have caused the messages to
userspace to be formatted differently with just a single message for
every SKB returned to userspace. It's possible that this isn't needed
for the tools that actually use this, but I don't even know what they
are so couldn't test that changing this behaviour would be acceptable.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2015-01-18 01:03:45 -05:00
..
ast.c dlm: use INFO for recovery messages 2014-02-14 11:54:44 -06:00
ast.h
config.c fs/dlm/config.c: convert simple_str to kstr 2014-06-06 16:08:17 -07:00
config.h
debug_fs.c dlm: Use seq_puts() instead of seq_printf() for constant strings 2014-11-05 14:13:09 -05:00
dir.c dlm: use INFO for recovery messages 2014-02-14 11:54:44 -06:00
dir.h
dlm_internal.h dlm: use INFO for recovery messages 2014-02-14 11:54:44 -06:00
Kconfig
lock.c dlm: adopt orphan locks 2014-11-19 14:48:02 -06:00
lock.h dlm: adopt orphan locks 2014-11-19 14:48:02 -06:00
lockspace.c fs/dlm/lockspace.c: convert simple_str to kstr 2014-06-06 16:08:18 -07:00
lockspace.h
lowcomms.c dlm: keep listening connection alive with sctp mode 2014-06-12 10:26:14 -05:00
lowcomms.h
lvb_table.h
main.c
Makefile
member.c dlm: use INFO for recovery messages 2014-02-14 11:54:44 -06:00
member.h
memory.c
memory.h
midcomms.c
midcomms.h
netlink.c netlink: make nlmsg_end() and genlmsg_end() void 2015-01-18 01:03:45 -05:00
plock.c locks: Remove unused conf argument from lm_grant 2014-09-09 16:01:06 -04:00
rcom.c dlm: fix missing endian conversion of rcom_status flags 2014-10-14 15:11:48 -05:00
rcom.h
recover.c dlm: use INFO for recovery messages 2014-02-14 11:54:44 -06:00
recover.h
recoverd.c dlm: use INFO for recovery messages 2014-02-14 11:54:44 -06:00
recoverd.h
requestqueue.c
requestqueue.h
user.c dlm: adopt orphan locks 2014-11-19 14:48:02 -06:00
user.h
util.c
util.h