tree fcc0f3e2d2e7fb16ee11a9de20d8d842e9766041
parent 1d339638a954edce06ffcaa15d883d322e9e8291
author Andy Shevchenko <andriy.shevchenko@linux.intel.com> 1602817891 -0700
committer Linus Torvalds <torvalds@linux-foundation.org> 1602871880 -0700

include/linux/list.h: add a macro to test if entry is pointing to the head

Add a macro to test if entry is pointing to the head of the list which is
useful in cases like:

  list_for_each_entry(pos, &head, member) {
    if (cond)
      break;
  }
  if (list_entry_is_head(pos, &head, member))
    return -ERRNO;

that allows to avoid additional variable to be added to track if loop has
not been stopped in the middle.

While here, convert list_for_each_entry*() family of macros to use a new one.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Cezary Rojewski <cezary.rojewski@intel.com>
Link: https://lkml.kernel.org/r/20200929134342.51489-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>