If we need to increase the tree depth, allocate a new node, and then
race with another thread that increased the tree depth before us, we'll
still have a preallocated node that might be used later.
If we then use that node for a new non-root node, it'll still have a
pointer to the old root instead of being zeroed - fix this by zeroing it
in the cmpxchg failure path.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
this code originally used the page allocator directly, but most code
shouldn't do that - PAGE_SIZE varies with architecture, and slab is
faster.
4k is also on the large side for typical usage, 512 bytes is a better
choice for typical usage that might be somewhat sparse.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
This patch adds genradix_peek_prev(), genradix_iter_rewind(), and
genradix_for_each_reverse(), for iterating backwards over a generic
radix tree.
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
When we started spreading new inode numbers throughout most of the 64
bit inode space, that triggered some corner case bugs, in particular
some integer overflows related to the radix tree code. Oops.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
When building with W=1, we get some warnings:
l CC lib/generic-radix-tree.o
lib/generic-radix-tree.c:39:10: warning: no previous prototype for 'genradix_root_to_depth' [-Wmissing-prototypes]
39 | unsigned genradix_root_to_depth(struct genradix_root *r)
| ^~~~~~~~~~~~~~~~~~~~~~
lib/generic-radix-tree.c:44:23: warning: no previous prototype for 'genradix_root_to_node' [-Wmissing-prototypes]
44 | struct genradix_node *genradix_root_to_node(struct genradix_root *r)
| ^~~~~~~~~~~~~~~~~~~~~
They're not used anywhere else, so make them static inline.
Link: http://lkml.kernel.org/r/46923.1565236485@turing-police
Signed-off-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Very simple radix tree implementation that supports storing arbitrary
size entries, up to PAGE_SIZE - upcoming patches will convert existing
flex_array users to genradixes. The new genradix code has a much
simpler API and implementation, and doesn't have a hard limit on the
number of elements like flex_array does.
Link: http://lkml.kernel.org/r/20181217131929.11727-5-kent.overstreet@gmail.com
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Eric Paris <eparis@parisplace.org>
Cc: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Pravin B Shelar <pshelar@ovn.org>
Cc: Shaohua Li <shli@kernel.org>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
