lib/test_maple_tree: add testing for maple tree

This is a test suite that uses the radix test infrastructure.  It has been
split into its own commit to allow for easier review of the maple tree
code.

The testing includes:
- Allocation of nodes
- gfp flag allocation checks
- Expansion & contraction of tree
- preallocation checks
- tree navigation by next/prev
- tree navigation by iterators (mas_for_each, etc)
- Number of nodes for a given number of entries
- Generic tree construction tests
- Addition and removal of entries in forward and reverse numerical indexes
- gap searching both forward and reverse
- Combining gaps by overwriting entries in different ways
- splitting right-most node
- splitting left-most node
- overwriting multiple slots
- overwriting across different levels of the tree
- overwriting the middle of a tree
- causing a 3-way split up to the root by overwriting the last slot and
  first slot of different nodes and spanning different levels
- RCU stress testing of the tree with threads
- Duplication of the tree by entry count
- Tests which were generated by fuzzers have been added.
- A large number of tests which come from recording crashing in a VM and
  reconstructing the tree (see check_erase2_set())

Link: https://lkml.kernel.org/r/20220906194824.2110408-8-Liam.Howlett@oracle.comSigned-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

tools/testing/radix-tree/Makefile

@@ -4,9 +4,9 @@ CFLAGS += -I. -I../../include -g -Og -Wall -D_LGPL_SOURCE -fsanitize=address \
 	  -fsanitize=undefined
 LDFLAGS += -fsanitize=address -fsanitize=undefined
 LDLIBS+= -lpthread -lurcu
-TARGETS = main idr-test multiorder xarray
+TARGETS = main idr-test multiorder xarray maple
 CORE_OFILES := xarray.o radix-tree.o idr.o linux.o test.o find_bit.o bitmap.o \
-			 slab.o
+			 slab.o maple.o
 OFILES = main.o $(CORE_OFILES) regression1.o regression2.o regression3.o \
 	 regression4.o tag_check.o multiorder.o idr-test.o iteration_check.o \
 	 iteration_check_2.o benchmark.o
@@ -29,6 +29,8 @@ idr-test: idr-test.o $(CORE_OFILES)
 
 xarray: $(CORE_OFILES)
 
+maple: $(CORE_OFILES)
+
 multiorder: multiorder.o $(CORE_OFILES)
 
 clean:
@@ -40,6 +42,7 @@ $(OFILES): Makefile *.h */*.h generated/map-shift.h \
 	../../include/linux/*.h \
 	../../include/asm/*.h \
 	../../../include/linux/xarray.h \
+	../../../include/linux/maple_tree.h \
 	../../../include/linux/radix-tree.h \
 	../../../include/linux/idr.h
 
@@ -51,6 +54,8 @@ idr.c: ../../../lib/idr.c
 
 xarray.o: ../../../lib/xarray.c ../../../lib/test_xarray.c
 
+maple.o: ../../../lib/maple_tree.c ../../../lib/test_maple_tree.c
+
 generated/map-shift.h:
 	@if ! grep -qws $(SHIFT) generated/map-shift.h; then		\
 		echo "#define XA_CHUNK_SHIFT $(SHIFT)" >		\