s390/crypto: Map EBUSY to EIO when key conversion fails repeatedly

When hardware persistently returns -EBUSY after exhausting retries,
the error propagates to crypto_finalize_*_request(). The crypto API's
completion wrapper treats -EBUSY as a queueing status and swallows it,
preventing the completion callback from firing. This causes callers
using crypto_wait_req() to block indefinitely.

Translate persistent -EBUSY to -EIO after retry exhaustion to ensure
proper error propagation and callback invocation.

Fixes: 6cd87cb5ef ("s390/crypto: Rework protected key AES for true asynch support")
Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Reviewed-by: Holger Dengler <dengler@linux.ibm.com>
Cc: stable@vger.kernel.org # 6.16+
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

arch/s390/crypto/paes_s390.c

@@ -220,6 +220,10 @@ static inline int convert_key(const u8 *key, unsigned int keylen,
 				      xflags);
 	}
 
+	/* But finally map -EBUSY to -EIO to indicate an IO failure */
+	if (rc == -EBUSY)
+		rc = -EIO;
+
 out:
 	pr_debug("rc=%d\n", rc);
 	return rc;

arch/s390/crypto/phmac_s390.c

@@ -341,6 +341,10 @@ static inline int convert_key(const u8 *key, unsigned int keylen,
 				      xflags);
 	}
 
+	/* But finally map -EBUSY to -EIO to indicate an IO failure */
+	if (rc == -EBUSY)
+		rc = -EIO;
+
 out:
 	pr_debug("rc=%d\n", rc);
 	return rc;