Re: [PATCH 00/15] trivial: Drop unlikely before IS_ERR(_OR_NULL)

[Vlastimil Babka <vbabka@suse.cz>]

On 07/31/2015 10:38 AM, Viresh Kumar wrote:
> Hi,
>
> This cleans up the usage of IS_ERR(_OR_NULL)(), where the callers have
> added additional unlikely compiler flag to them. It also fixes the
> definition of IS_ERR_OR_NULL(), to use unlikely for all checks it does.

[+CC Steven Rostedt]

Any idea what the compiler does in the case of
"if (likely(IS_ERR(...)))"? There are apparently such cases in the source.

does the "likely" somehow override the "unlikely" of IS_ERR, or is the 
resulting code a mess?

Vlastimil

> Viresh Kumar (15):
>    err.h: add (missing) unlikely() to IS_ERR_OR_NULL()
>    PM / OPP: Drop unlikely before IS_ERR(_OR_NULL)
>    drivers: devfreq: Drop unlikely before IS_ERR(_OR_NULL)
>    drivers: gpu: Drop unlikely before IS_ERR(_OR_NULL)
>    drivers: input: Drop unlikely before IS_ERR(_OR_NULL)
>    drivers: md: Drop unlikely before IS_ERR(_OR_NULL)
>    drivers: misc: Drop unlikely before IS_ERR(_OR_NULL)
>    drivers: net: Drop unlikely before IS_ERR(_OR_NULL)
>    drivers: rtc: Drop unlikely before IS_ERR(_OR_NULL)
>    drivers: staging: Drop unlikely before IS_ERR(_OR_NULL)
>    drivers: target: Drop unlikely before IS_ERR(_OR_NULL)
>    fs: Drop unlikely before IS_ERR(_OR_NULL)
>    blk-cgroup: Drop unlikely before IS_ERR(_OR_NULL)
>    mm: Drop unlikely before IS_ERR(_OR_NULL)
>    net: Drop unlikely before IS_ERR(_OR_NULL)
>
>   drivers/base/power/opp.c                             | 6 +++---
>   drivers/devfreq/devfreq.c                            | 4 ++--
>   drivers/gpu/drm/ttm/ttm_tt.c                         | 4 ++--
>   drivers/gpu/drm/vmwgfx/vmwgfx_context.c              | 2 +-
>   drivers/gpu/drm/vmwgfx/vmwgfx_drv.c                  | 2 +-
>   drivers/input/mouse/alps.c                           | 2 +-
>   drivers/md/dm-snap-persistent.c                      | 2 +-
>   drivers/md/dm-verity.c                               | 2 +-
>   drivers/md/persistent-data/dm-block-manager.c        | 8 ++++----
>   drivers/misc/c2port/core.c                           | 2 +-
>   drivers/net/ethernet/ti/netcp_core.c                 | 4 ++--
>   drivers/rtc/interface.c                              | 2 +-
>   drivers/rtc/rtc-bfin.c                               | 2 +-
>   drivers/rtc/rtc-gemini.c                             | 2 +-
>   drivers/staging/android/ashmem.c                     | 2 +-
>   drivers/staging/lustre/include/linux/libcfs/libcfs.h | 2 +-
>   drivers/staging/lustre/lustre/obdclass/lu_object.c   | 6 +++---
>   drivers/target/tcm_fc/tfc_cmd.c                      | 2 +-
>   fs/cifs/readdir.c                                    | 2 +-
>   fs/ecryptfs/inode.c                                  | 2 +-
>   fs/ext4/extents.c                                    | 6 +++---
>   fs/ext4/namei.c                                      | 2 +-
>   fs/namei.c                                           | 4 ++--
>   fs/ncpfs/dir.c                                       | 2 +-
>   fs/nfs/objlayout/objio_osd.c                         | 2 +-
>   fs/proc/proc_sysctl.c                                | 2 +-
>   include/linux/blk-cgroup.h                           | 2 +-
>   include/linux/err.h                                  | 2 +-
>   mm/huge_memory.c                                     | 2 +-
>   net/openvswitch/datapath.c                           | 2 +-
>   net/sctp/socket.c                                    | 2 +-
>   net/socket.c                                         | 6 +++---
>   32 files changed, 47 insertions(+), 47 deletions(-)
>