[PATCH v3 1/4] s390/crypto: Replace cond_resched() with msleep(1)

With [1] cond_resched() is always compiled away and becomes a no-op.

The comments for all cond_resched() calls in crypto code however indicate
that the current process should be scheduled away to avoid instant
re-invocation of a callback. This is not what cond_resched() would do or
did.

Instead of just removing the cond_resched() calls, replace them with
msleep() calls, as suggested by Holger Dengler. This forces the current
task to be scheduled away (sleeps) like originally intended.

[1] commit 7dadeaa6e851 ("sched: Further restrict the preemption modes")

Signed-off-by: Heiko Carstens <[email protected]>
---
 arch/s390/crypto/paes_s390.c  | 8 ++++----
 arch/s390/crypto/phmac_s390.c | 4 ++--
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/s390/crypto/paes_s390.c b/arch/s390/crypto/paes_s390.c
index 8cfe6166c193..511cb6105436 100644
--- a/arch/s390/crypto/paes_s390.c
+++ b/arch/s390/crypto/paes_s390.c
@@ -555,7 +555,7 @@ static int ecb_paes_do_one_request(struct crypto_engine *engine, void *areq)
 		 * To avoid immediately re-invocation of this callback,
 		 * tell the scheduler to voluntarily give up the CPU here.
 		 */
-		cond_resched();
+		msleep(1);
 		pr_debug("rescheduling request\n");
 		return -ENOSPC;
 	} else if (rc) {
@@ -821,7 +821,7 @@ static int cbc_paes_do_one_request(struct crypto_engine *engine, void *areq)
 		 * To avoid immediately re-invocation of this callback,
 		 * tell the scheduler to voluntarily give up the CPU here.
 		 */
-		cond_resched();
+		msleep(1);
 		pr_debug("rescheduling request\n");
 		return -ENOSPC;
 	} else if (rc) {
@@ -1129,7 +1129,7 @@ static int ctr_paes_do_one_request(struct crypto_engine *engine, void *areq)
 		 * To avoid immediately re-invocation of this callback,
 		 * tell the scheduler to voluntarily give up the CPU here.
 		 */
-		cond_resched();
+		msleep(1);
 		pr_debug("rescheduling request\n");
 		return -ENOSPC;
 	} else if (rc) {
@@ -1572,7 +1572,7 @@ static int xts_paes_do_one_request(struct crypto_engine *engine, void *areq)
 		 * To avoid immediately re-invocation of this callback,
 		 * tell the scheduler to voluntarily give up the CPU here.
 		 */
-		cond_resched();
+		msleep(1);
 		pr_debug("rescheduling request\n");
 		return -ENOSPC;
 	} else if (rc) {
diff --git a/arch/s390/crypto/phmac_s390.c b/arch/s390/crypto/phmac_s390.c
index 03ca33ffe6cc..da76c7beb184 100644
--- a/arch/s390/crypto/phmac_s390.c
+++ b/arch/s390/crypto/phmac_s390.c
@@ -895,7 +895,7 @@ static int phmac_do_one_request(struct crypto_engine *engine, void *areq)
 			 * tell scheduler to voluntarily give up the CPU here.
 			 */
 			pr_debug("rescheduling request\n");
-			cond_resched();
+			msleep(1);
 			return -ENOSPC;
 		} else if (rc) {
 			hwh_advance(hwh, rc);
@@ -916,7 +916,7 @@ static int phmac_do_one_request(struct crypto_engine *engine, void *areq)
 			 * tell scheduler to voluntarily give up the CPU here.
 			 */
 			pr_debug("rescheduling request\n");
-			cond_resched();
+			msleep(1);
 			return -ENOSPC;
 		}
 		break;
-- 
2.53.0