Merge tag 'kvm-arm-for-v4.4-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git...

[firefly-linux-kernel-4.4.55.git] / lib / crc-t10dif.c

diff --git a/lib/crc-t10dif.c b/lib/crc-t10dif.c
index 43bc5b071f9698847e66353e867c7b4771628475..1ad33e555805a22cc901d4ed029826eea0b78250 100644 (file)
--- a/lib/crc-t10dif.c
+++ b/lib/crc-t10dif.c
@@ -14,10 +14,12 @@
 #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)
+__u16 crc_t10dif_update(__u16 crc, const unsigned char *buffer, size_t len)
 {
        struct {
                struct shash_desc shash;
@@ -25,21 +27,34 @@ __u16 crc_t10dif(const unsigned char *buffer, size_t len)
        } desc;
        int err;
 
+       if (static_key_false(&crct10dif_fallback))
+               return crc_t10dif_generic(crc, buffer, len);
+
        desc.shash.tfm = crct10dif_tfm;
        desc.shash.flags = 0;
-       *(__u16 *)desc.ctx = 0;
+       *(__u16 *)desc.ctx = crc;
 
        err = crypto_shash_update(&desc.shash, buffer, len);
        BUG_ON(err);
 
        return *(__u16 *)desc.ctx;
 }
+EXPORT_SYMBOL(crc_t10dif_update);
+
+__u16 crc_t10dif(const unsigned char *buffer, size_t len)
+{
+       return crc_t10dif_update(0, buffer, len);
+}
 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)