radix tree test suite: add kmem_cache_set_non_kernel()

kmem_cache_set_non_kernel() is a mechanism to allow a certain number of
kmem_cache_alloc requests to succeed even when GFP_KERNEL is not set in
the flags.  This functionality allows for testing different paths though
the code.

Link: https://lkml.kernel.org/r/20220906194824.2110408-4-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
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: 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>

diff --git a/tools/testing/radix-tree/linux.c b/tools/testing/radix-tree/linux.c
index d5c1bcb..277aa8b 100644 (file)
--- a/tools/testing/radix-tree/linux.c
+++ b/tools/testing/radix-tree/linux.c
@@ -23,15 +23,26 @@ struct kmem_cache {
        int nr_objs;
        void *objs;
        void (*ctor)(void *);
+       unsigned int non_kernel;
 };
 
+void kmem_cache_set_non_kernel(struct kmem_cache *cachep, unsigned int val)
+{
+       cachep->non_kernel = val;
+}
+
 void *kmem_cache_alloc_lru(struct kmem_cache *cachep, struct list_lru *lru,
                int gfp)
+
 {
        void *p;
 
-       if (!(gfp & __GFP_DIRECT_RECLAIM))
-               return NULL;
+       if (!(gfp & __GFP_DIRECT_RECLAIM)) {
+               if (!cachep->non_kernel)
+                       return NULL;
+
+               cachep->non_kernel--;
+       }
 
        pthread_mutex_lock(&cachep->lock);
        if (cachep->nr_objs) {
@@ -90,5 +101,6 @@ kmem_cache_create(const char *name, unsigned int size, unsigned int align,
        ret->nr_objs = 0;
        ret->objs = NULL;
        ret->ctor = ctor;
+       ret->non_kernel = 0;
        return ret;
 }