The eytzinger code was previously relying on the following wrap-around
properties and their "eytzinger0" equivalents:
eytzinger1_prev(0, size) == eytzinger1_last(size)
eytzinger1_next(0, size) == eytzinger1_first(size)
However, these properties are no longer relied upon and no longer
necessary, so remove the corresponding asserts and forbid the use of
eytzinger1_prev(0, size) and eytzinger1_next(0, size).
This allows to further simplify the code in eytzinger1_next() and
eytzinger1_prev(): where the left shifting happens, eytzinger1_next() is
trying to move i to the lowest child on the left, which is equivalent to
doubling i until the next doubling would cause it to be greater than
size. This is implemented by shifting i to the left so that the most
significant bits align and then shifting i to the right by one if the
result is greater than size.
Likewise, eytzinger1_prev() is trying to move to the lowest child on the
right; the same applies here.
The 1-offset in (size - 1) in eytzinger1_next() isn't needed at all, but
the equivalent offset in eytzinger1_prev() is surprisingly needed to
preserve the 'eytzinger1_prev(0, size) == eytzinger1_last(size)'
property. However, since we no longer support that property, we can get
rid of these offsets as well. This saves one addition in each function
and makes the code less confusing.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Several of the algorithms on eytzinger trees are implemented in terms of
the eytzinger0 primitives. However, those algorithms can just as easily
be expressed in terms of the eytzinger1 primitives, and that leads to
better and easier to understand code. Start by converting
eytzinger0_find().
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Implement eytzinger0_find_ge() directly instead of implementing it in
terms of eytzinger0_find_le() and adjusting the result.
This turns eytzinger0_find_ge() into a minimum search, so when there are
duplicate elements, the result of eytzinger0_find_ge() will now always
point at the first matching element.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Instead of implementing eytzinger0_find_gt() in terms of
eytzinger0_find_le() and adjusting the result, implement it directly.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Replace the over-complicated implementation of eytzinger0_find_le() by
an equivalent, simpler version.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
eytzinger0_find_le() is also easy to concert to 1-based eytzinger (but
see the next commit).
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Add an eytzinger0_for_each_prev() macro for iterating through an
eytzinger array in reverse.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
When EYTZINGER_DEBUG is defined, <linux/bug.h> needs to be included.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
The transaction commit path takes mark_lock, so we shouldn't be holding
it; use a bpos as an iterator so that we can drop and retake.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
- fix return types: promoting from unsigned to ssize_t does not do what
we want here, and was pointless since the rest of the eytzinger code
is u32
- nr, not size
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Pull out eytzinger.c and kill eytzinger_cmp_fn. We now provide
eytzinger0_sort and eytzinger0_sort_r, which use the standard cmp_func_t
and cmp_r_func_t callbacks.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
Initially forked from drivers/md/bcache, bcachefs is a new copy-on-write
filesystem with every feature you could possibly want.
Website: https://bcachefs.org
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
