From: Ayush Sawal <ayush.sawal@chelsio.com>
Date: Wed, 10 Jun 2020 02:54:32 +0530
Subject: Crypto/chcr: Checking cra_refcnt before unregistering the algorithms
Patch-mainline: v5.8-rc1
Git-commit: 8b9914cd723bfce8dbff65bd135563f887dcb19d
References: jsc#SLE-15129

This patch puts a check for algorithm unregister, to avoid removal of
driver if the algorithm is under use.

Signed-off-by: Ayush Sawal <ayush.sawal@chelsio.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/crypto/chelsio/chcr_algo.c |   18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

--- a/drivers/crypto/chelsio/chcr_algo.c
+++ b/drivers/crypto/chelsio/chcr_algo.c
@@ -4424,22 +4424,32 @@ static int chcr_unregister_alg(void)
 	for (i = 0; i < ARRAY_SIZE(driver_algs); i++) {
 		switch (driver_algs[i].type & CRYPTO_ALG_TYPE_MASK) {
 		case CRYPTO_ALG_TYPE_SKCIPHER:
-			if (driver_algs[i].is_registered)
+			if (driver_algs[i].is_registered && refcount_read(
+			    &driver_algs[i].alg.skcipher.base.cra_refcnt)
+			    == 1) {
 				crypto_unregister_skcipher(
 						&driver_algs[i].alg.skcipher);
+				driver_algs[i].is_registered = 0;
+			}
 			break;
 		case CRYPTO_ALG_TYPE_AEAD:
-			if (driver_algs[i].is_registered)
+			if (driver_algs[i].is_registered && refcount_read(
+			    &driver_algs[i].alg.aead.base.cra_refcnt) == 1) {
 				crypto_unregister_aead(
 						&driver_algs[i].alg.aead);
+				driver_algs[i].is_registered = 0;
+			}
 			break;
 		case CRYPTO_ALG_TYPE_AHASH:
-			if (driver_algs[i].is_registered)
+			if (driver_algs[i].is_registered && refcount_read(
+			    &driver_algs[i].alg.hash.halg.base.cra_refcnt)
+			    == 1) {
 				crypto_unregister_ahash(
 						&driver_algs[i].alg.hash);
+				driver_algs[i].is_registered = 0;
+			}
 			break;
 		}
-		driver_algs[i].is_registered = 0;
 	}
 	return 0;
 }