linux-kernel - [PATCH v3 02/66] radix tree test suite: Add kmem_cache_set_non

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Date:   Tue, 5 Oct 2021 01:30:26 +0000
From:   Liam Howlett <liam.howlett@...cle.com>
To:     "maple-tree@...ts.infradead.org" <maple-tree@...ts.infradead.org>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        David Hildenbrand <david@...hat.com>,
        Douglas Gilbert <dgilbert@...erlog.com>
CC:     Song Liu <songliubraving@...com>,
        Davidlohr Bueso <dave@...olabs.net>,
        "Paul E . McKenney" <paulmck@...nel.org>,
        Matthew Wilcox <willy@...radead.org>,
        David Rientjes <rientjes@...gle.com>,
        Axel Rasmussen <axelrasmussen@...gle.com>,
        Suren Baghdasaryan <surenb@...gle.com>,
        Vlastimil Babka <vbabka@...e.cz>,
        Rik van Riel <riel@...riel.com>,
        Peter Zijlstra <peterz@...radead.org>
Subject: [PATCH v3 02/66] radix tree test suite: Add
 kmem_cache_set_non_kernel()

From: "Liam R. Howlett" <Liam.Howlett@...cle.com>

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.

Signed-off-by: Liam R. Howlett <Liam.Howlett@...cle.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@...radead.org>
---
 tools/testing/radix-tree/linux.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/tools/testing/radix-tree/linux.c b/tools/testing/radix-tree/linux.c
index 2d9c59df60de..00ee01a14652 100644
--- a/tools/testing/radix-tree/linux.c
+++ b/tools/testing/radix-tree/linux.c
@@ -24,14 +24,24 @@ 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(struct kmem_cache *cachep, 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) {
@@ -116,5 +126,6 @@ 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;
 }
-- 
2.30.2