Hi,
While pondering some issues with DAX and how it uses the radix tree I
conceived the following patches. I don't know if they'll be useful
but I thought I would post them in case they are helpful.
The first is quite independent of the others - it removes some DAX
specific #defines from radix-tree.h which is a generic ADT.
The second makes an extra bit available when exception data is
stored in the radix tree.
The third uses this bit to provide a sleeping lock. With this
it should be possible to delete exceptional entries from the radix
tree in a race-free way without external locking.
Like the page lock it requires an external set of wait_queue_heads.
The same ones used for page_lock would be suitable.
Note that this code is only compile tested.
NeilBrown
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NeilBrown (3):
DAX: move RADIX_DAX_ definitions to dax.c
radix-tree: make 'indirect' bit available to exception entries.
radix-tree: support locking of individual exception entries.
fs/dax.c | 9 ++
include/linux/radix-tree.h | 28 +++++---
lib/radix-tree.c | 160 ++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 185 insertions(+), 12 deletions(-)
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