• Nick Piggin's avatar
    fs: remove extra lookup in __lookup_hash · b04f784e
    Nick Piggin authored
    fs: remove extra lookup in __lookup_hash
    
    Optimize lookup for create operations, where no dentry should often be
    common-case. In cases where it is not, such as unlink, the added overhead
    is much smaller than the removed.
    
    Also, move comments about __d_lookup racyness to the __d_lookup call site.
    d_lookup is intuitive; __d_lookup is what needs commenting. So in that same
    vein, add kerneldoc comments to __d_lookup and clean up some of the comments:
    
    - We are interested in how the RCU lookup works here, particularly with
      renames. Make that explicit, and point to the document where it is explained
      in more detail.
    - RCU is pretty standard now, and macros make implementations pretty mindless.
      If we want to know about RCU barrier details, we look in RCU code.
    - Delete some boring legacy comments because we don't care much about how the
      code used to work, more about the interesting parts of how it works now. So
      comments about lazy LRU may be interesting, but would better be done in the
      LRU or refcount management code.
    Signed-off-by: default avatarNick Piggin <npiggin@kernel.dk>
    Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
    b04f784e
dcache.c 62.1 KB