Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6

Pull crypto updates from Herbert Xu:
 "Here is the crypto update for 4.15:

  API:

   - Disambiguate EBUSY when queueing crypto request by adding ENOSPC.
     This change touches code outside the crypto API.
   - Reset settings when empty string is written to rng_current.

  Algorithms:

   - Add OSCCA SM3 secure hash.

  Drivers:

   - Remove old mv_cesa driver (replaced by marvell/cesa).
   - Enable rfc3686/ecb/cfb/ofb AES in crypto4xx.
   - Add ccm/gcm AES in crypto4xx.
   - Add support for BCM7278 in iproc-rng200.
   - Add hash support on Exynos in s5p-sss.
   - Fix fallback-induced error in vmx.
   - Fix output IV in atmel-aes.
   - Fix empty GCM hash in mediatek.

  Others:

   - Fix DoS potential in lib/mpi.
   - Fix potential out-of-order issues with padata"

* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (162 commits)
  lib/mpi: call cond_resched() from mpi_powm() loop
  crypto: stm32/hash - Fix return issue on update
  crypto: dh - Remove pointless checks for NULL 'p' and 'g'
  crypto: qat - Clean up error handling in qat_dh_set_secret()
  crypto: dh - Don't permit 'key' or 'g' size longer than 'p'
  crypto: dh - Don't permit 'p' to be 0
  crypto: dh - Fix double free of ctx->p
  hwrng: iproc-rng200 - Add support for BCM7278
  dt-bindings: rng: Document BCM7278 RNG200 compatible
  crypto: chcr - Replace _manual_ swap with swap macro
  crypto: marvell - Add a NULL entry at the end of mv_cesa_plat_id_table[]
  hwrng: virtio - Virtio RNG devices need to be re-registered after suspend/resume
  crypto: atmel - remove empty functions
  crypto: ecdh - remove empty exit()
  MAINTAINERS: update maintainer for qat
  crypto: caam - remove unused param of ctx_map_to_sec4_sg()
  crypto: caam - remove unneeded edesc zeroization
  crypto: atmel-aes - Reset the controller before each use
  crypto: atmel-aes - properly set IV after {en,de}crypt
  hwrng: core - Reset user selected rng by writing "" to rng_current
  ...

1 files changed, 33 insertions, 20 deletions

diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
index 9701ac7d8b47..657b8770b6b9 100644
--- a/drivers/char/hw_random/core.c
+++ b/drivers/char/hw_random/core.c
@@ -292,26 +292,48 @@ static struct miscdevice rng_miscdev = {
 	.groups		= rng_dev_groups,
 };
 
+static int enable_best_rng(void)
+{
+	int ret = -ENODEV;
+
+	BUG_ON(!mutex_is_locked(&rng_mutex));
+
+	/* rng_list is sorted by quality, use the best (=first) one */
+	if (!list_empty(&rng_list)) {
+		struct hwrng *new_rng;
+
+		new_rng = list_entry(rng_list.next, struct hwrng, list);
+		ret = ((new_rng == current_rng) ? 0 : set_current_rng(new_rng));
+		if (!ret)
+			cur_rng_set_by_user = 0;
+	}
+
+	return ret;
+}
+
 static ssize_t hwrng_attr_current_store(struct device *dev,
 					struct device_attribute *attr,
 					const char *buf, size_t len)
 {
-	int err;
+	int err = -ENODEV;
 	struct hwrng *rng;
 
 	err = mutex_lock_interruptible(&rng_mutex);
 	if (err)
 		return -ERESTARTSYS;
-	err = -ENODEV;
-	list_for_each_entry(rng, &rng_list, list) {
-		if (sysfs_streq(rng->name, buf)) {
-			err = 0;
-			cur_rng_set_by_user = 1;
-			if (rng != current_rng)
+
+	if (sysfs_streq(buf, "")) {
+		err = enable_best_rng();
+	} else {
+		list_for_each_entry(rng, &rng_list, list) {
+			if (sysfs_streq(rng->name, buf)) {
+				cur_rng_set_by_user = 1;
 				err = set_current_rng(rng);
-			break;
+				break;
+			}
 		}
 	}
+
 	mutex_unlock(&rng_mutex);
 
 	return err ? : len;
@@ -423,7 +445,7 @@ static void start_khwrngd(void)
 {
 	hwrng_fill = kthread_run(hwrng_fillfn, NULL, "hwrng");
 	if (IS_ERR(hwrng_fill)) {
-		pr_err("hwrng_fill thread creation failed");
+		pr_err("hwrng_fill thread creation failed\n");
 		hwrng_fill = NULL;
 	}
 }
@@ -493,17 +515,8 @@ void hwrng_unregister(struct hwrng *rng)
 	mutex_lock(&rng_mutex);
 
 	list_del(&rng->list);
-	if (current_rng == rng) {
-		drop_current_rng();
-		cur_rng_set_by_user = 0;
-		/* rng_list is sorted by quality, use the best (=first) one */
-		if (!list_empty(&rng_list)) {
-			struct hwrng *new_rng;
-
-			new_rng = list_entry(rng_list.next, struct hwrng, list);
-			set_current_rng(new_rng);
-		}
-	}
+	if (current_rng == rng)
+		enable_best_rng();
 
 	if (list_empty(&rng_list)) {
 		mutex_unlock(&rng_mutex);