[PATCH 0/2] xarray: free unused spare node after range creation

[Andrew Morton <akpm@linux-foundation.org>]

xas_nomem() can leave a spare xa_node in an XA state when another user
populates the tree before xas_create_range() retries.  Free an unused
spare at the end of range creation, and add a deterministic lib/test_xarray
check for that path.  The fix is first and the test is second.

The test patch was held on both sides of a kernel A/B run while only the
fix was removed and restored.  Without the fix, its spare-node assertion
failed (158825705 of 158825706 checks passed).  With the fix, all
158825706 checks passed.  Both runs used the same verified guest test
script.

Shardul Bankar (1):
  lib: xarray: free unused spare node in xas_create_range()

Andrew Morton (1):
  lib/test_xarray: check unused spare node after range creation

 lib/test_xarray.c | 31 +++++++++++++++++++++++++++++++
 lib/xarray.c      |  7 ++++++-
 2 files changed, 37 insertions(+), 1 deletion(-)