X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2Fcrc-t10dif.c;h=dfe6ec17c0a5fa774ec34d23de696be7b99a6182;hb=32665f2bbfed2e325d37236d9b0071a11a69124e;hp=43bc5b071f9698847e66353e867c7b4771628475;hpb=5a7d8a28080caed7fd4cb1b81d092adac4445e8e;p=firefly-linux-kernel-4.4.55.git

diff --git a/lib/crc-t10dif.c b/lib/crc-t10dif.c
index 43bc5b071f96..dfe6ec17c0a5 100644
--- a/lib/crc-t10dif.c
+++ b/lib/crc-t10dif.c
@@ -14,8 +14,10 @@
 #include <linux/err.h>
 #include <linux/init.h>
 #include <crypto/hash.h>
+#include <linux/static_key.h>
 
 static struct crypto_shash *crct10dif_tfm;
+static struct static_key crct10dif_fallback __read_mostly;
 
 __u16 crc_t10dif(const unsigned char *buffer, size_t len)
 {
@@ -25,6 +27,9 @@ __u16 crc_t10dif(const unsigned char *buffer, size_t len)
 	} desc;
 	int err;
 
+	if (static_key_false(&crct10dif_fallback))
+		return crc_t10dif_generic(0, buffer, len);
+
 	desc.shash.tfm = crct10dif_tfm;
 	desc.shash.flags = 0;
 	*(__u16 *)desc.ctx = 0;
@@ -39,7 +44,11 @@ EXPORT_SYMBOL(crc_t10dif);
 static int __init crc_t10dif_mod_init(void)
 {
 	crct10dif_tfm = crypto_alloc_shash("crct10dif", 0, 0);
-	return PTR_RET(crct10dif_tfm);
+	if (IS_ERR(crct10dif_tfm)) {
+		static_key_slow_inc(&crct10dif_fallback);
+		crct10dif_tfm = NULL;
+	}
+	return 0;
 }
 
 static void __exit crc_t10dif_mod_fini(void)