[PATCH v4 14/24] s390/zcrypt/pkey: Rework ep11 findcard() implementation and callers

[Harald Freudenberger <freude@linux.ibm.com>]

Rework the memory usage of the ep11 findcard() implementation:
- findcard does not allocate memory for the list of apqns
  any more.
- the callers are now responsible to provide an array of
  apqns to store the matching apqns into.

Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
---
 drivers/s390/crypto/pkey_ep11.c       | 19 +++++++---------
 drivers/s390/crypto/zcrypt_ep11misc.c | 31 ++++++---------------------
 drivers/s390/crypto/zcrypt_ep11misc.h | 12 +++++------
 3 files changed, 20 insertions(+), 42 deletions(-)

diff --git a/drivers/s390/crypto/pkey_ep11.c b/drivers/s390/crypto/pkey_ep11.c
index 5b033ca3e828..b970f0be84be 100644
--- a/drivers/s390/crypto/pkey_ep11.c
+++ b/drivers/s390/crypto/pkey_ep11.c
@@ -73,7 +73,7 @@ static int ep11_apqns4key(const u8 *key, u32 keylen, u32 flags,
 			  struct pkey_apqn *apqns, size_t *nr_apqns)
 {
 	struct keytoken_header *hdr = (struct keytoken_header *)key;
-	u32 _nr_apqns, *_apqns = NULL;
+	u32 _apqns[MAXAPQNSINLIST], _nr_apqns = ARRAY_SIZE(_apqns);
 	int rc;
 
 	if (!flags)
@@ -98,7 +98,7 @@ static int ep11_apqns4key(const u8 *key, u32 keylen, u32 flags,
 			minhwtype = ZCRYPT_CEX7;
 			api = ap_is_se_guest() ? EP11_API_V6 : EP11_API_V4;
 		}
-		rc = ep11_findcard2(&_apqns, &_nr_apqns, 0xFFFF, 0xFFFF,
+		rc = ep11_findcard2(_apqns, &_nr_apqns, 0xFFFF, 0xFFFF,
 				    minhwtype, api, kb->wkvp);
 		if (rc)
 			goto out;
@@ -115,7 +115,7 @@ static int ep11_apqns4key(const u8 *key, u32 keylen, u32 flags,
 			minhwtype = ZCRYPT_CEX7;
 			api = ap_is_se_guest() ? EP11_API_V6 : EP11_API_V4;
 		}
-		rc = ep11_findcard2(&_apqns, &_nr_apqns, 0xFFFF, 0xFFFF,
+		rc = ep11_findcard2(_apqns, &_nr_apqns, 0xFFFF, 0xFFFF,
 				    minhwtype, api, kb->wkvp);
 		if (rc)
 			goto out;
@@ -135,7 +135,6 @@ static int ep11_apqns4key(const u8 *key, u32 keylen, u32 flags,
 	*nr_apqns = _nr_apqns;
 
 out:
-	kfree(_apqns);
 	pr_debug("rc=%d\n", rc);
 	return rc;
 }
@@ -144,7 +143,7 @@ static int ep11_apqns4type(enum pkey_key_type ktype,
 			   u8 cur_mkvp[32], u8 alt_mkvp[32], u32 flags,
 			   struct pkey_apqn *apqns, size_t *nr_apqns)
 {
-	u32 _nr_apqns, *_apqns = NULL;
+	u32 _apqns[MAXAPQNSINLIST], _nr_apqns = ARRAY_SIZE(_apqns);
 	int rc;
 
 	zcrypt_wait_api_operational();
@@ -158,7 +157,7 @@ static int ep11_apqns4type(enum pkey_key_type ktype,
 		if (flags & PKEY_FLAGS_MATCH_CUR_MKVP)
 			wkvp = cur_mkvp;
 		api = ap_is_se_guest() ? EP11_API_V6 : EP11_API_V4;
-		rc = ep11_findcard2(&_apqns, &_nr_apqns, 0xFFFF, 0xFFFF,
+		rc = ep11_findcard2(_apqns, &_nr_apqns, 0xFFFF, 0xFFFF,
 				    ZCRYPT_CEX7, api, wkvp);
 		if (rc)
 			goto out;
@@ -178,7 +177,6 @@ static int ep11_apqns4type(enum pkey_key_type ktype,
 	*nr_apqns = _nr_apqns;
 
 out:
-	kfree(_apqns);
 	pr_debug("rc=%d\n", rc);
 	return rc;
 }
@@ -423,7 +421,7 @@ static int ep11_verifykey(const u8 *key, u32 keylen,
 			  u32 *keytype, u32 *keybitsize, u32 *flags)
 {
 	struct keytoken_header *hdr = (struct keytoken_header *)key;
-	u32 nr_apqns, *apqns = NULL;
+	u32 apqns[MAXAPQNSINLIST], nr_apqns = ARRAY_SIZE(apqns);
 	int rc;
 
 	if (keylen < sizeof(*hdr))
@@ -443,7 +441,7 @@ static int ep11_verifykey(const u8 *key, u32 keylen,
 		*keybitsize = kb->head.bitlen;
 
 		api = ap_is_se_guest() ? EP11_API_V6 : EP11_API_V4;
-		rc = ep11_findcard2(&apqns, &nr_apqns, *card, *dom,
+		rc = ep11_findcard2(apqns, &nr_apqns, *card, *dom,
 				    ZCRYPT_CEX7, api,
 				    ep11_kb_wkvp(key, keylen));
 		if (rc)
@@ -467,7 +465,7 @@ static int ep11_verifykey(const u8 *key, u32 keylen,
 		*keybitsize = kh->bitlen;
 
 		api = ap_is_se_guest() ? EP11_API_V6 : EP11_API_V4;
-		rc = ep11_findcard2(&apqns, &nr_apqns, *card, *dom,
+		rc = ep11_findcard2(apqns, &nr_apqns, *card, *dom,
 				    ZCRYPT_CEX7, api,
 				    ep11_kb_wkvp(key, keylen));
 		if (rc)
@@ -484,7 +482,6 @@ static int ep11_verifykey(const u8 *key, u32 keylen,
 	}
 
 out:
-	kfree(apqns);
 	pr_debug("rc=%d\n", rc);
 	return rc;
 }
diff --git a/drivers/s390/crypto/zcrypt_ep11misc.c b/drivers/s390/crypto/zcrypt_ep11misc.c
index b545fbb3ca7d..1c9250a4e7f2 100644
--- a/drivers/s390/crypto/zcrypt_ep11misc.c
+++ b/drivers/s390/crypto/zcrypt_ep11misc.c
@@ -1523,14 +1523,14 @@ int ep11_kblob2protkey(u16 card, u16 dom,
 }
 EXPORT_SYMBOL(ep11_kblob2protkey);
 
-int ep11_findcard2(u32 **apqns, u32 *nr_apqns, u16 cardnr, u16 domain,
+int ep11_findcard2(u32 *apqns, u32 *nr_apqns, u16 cardnr, u16 domain,
 		   int minhwtype, int minapi, const u8 *wkvp)
 {
 	struct zcrypt_device_status_ext *device_status;
-	u32 *_apqns = NULL, _nr_apqns = 0;
-	int i, card, dom, rc;
 	struct ep11_domain_info edi;
 	struct ep11_card_info eci;
+	u32 _nr_apqns = 0;
+	int i, card, dom;
 
 	/* occupy the device status memory */
 	mutex_lock(&dev_status_mem_mutex);
@@ -1542,13 +1542,6 @@ int ep11_findcard2(u32 **apqns, u32 *nr_apqns, u16 cardnr, u16 domain,
 				      ZCRYPT_DEV_STATUS_CARD_MAX,
 				      ZCRYPT_DEV_STATUS_QUEUE_MAX);
 
-	/* allocate 1k space for up to 256 apqns */
-	_apqns = kmalloc_array(256, sizeof(u32), GFP_KERNEL);
-	if (!_apqns) {
-		rc = -ENOMEM;
-		goto out;
-	}
-
 	/* walk through all the crypto apqnss */
 	for (i = 0; i < ZCRYPT_DEV_STATUS_ENTRIES; i++) {
 		card = AP_QID_CARD(device_status[i].qid);
@@ -1585,25 +1578,15 @@ int ep11_findcard2(u32 **apqns, u32 *nr_apqns, u16 cardnr, u16 domain,
 				continue;
 		}
 		/* apqn passed all filtering criterons, add to the array */
-		if (_nr_apqns < 256)
-			_apqns[_nr_apqns++] = (((u16)card) << 16) | ((u16)dom);
+		if (_nr_apqns < *nr_apqns)
+			apqns[_nr_apqns++] = (((u16)card) << 16) | ((u16)dom);
 	}
 
-	/* nothing found ? */
-	if (!_nr_apqns) {
-		kfree(_apqns);
-		rc = -ENODEV;
-	} else {
-		/* no re-allocation, simple return the _apqns array */
-		*apqns = _apqns;
-		*nr_apqns = _nr_apqns;
-		rc = 0;
-	}
+	*nr_apqns = _nr_apqns;
 
-out:
 	mutex_unlock(&dev_status_mem_mutex);
 
-	return rc;
+	return _nr_apqns ? 0 : -ENODEV;
 }
 EXPORT_SYMBOL(ep11_findcard2);
 
diff --git a/drivers/s390/crypto/zcrypt_ep11misc.h b/drivers/s390/crypto/zcrypt_ep11misc.h
index dc1e418a6db1..2abd77aa16cf 100644
--- a/drivers/s390/crypto/zcrypt_ep11misc.h
+++ b/drivers/s390/crypto/zcrypt_ep11misc.h
@@ -136,14 +136,12 @@ int ep11_clr2keyblob(u16 cardnr, u16 domain, u32 keybitsize, u32 keygenflags,
  *   key for this domain. When a wkvp is given there will always be a re-fetch
  *   of the domain info for the potential apqn - so this triggers an request
  *   reply to each apqn eligible.
- * The array of apqn entries is allocated with kmalloc and returned in *apqns;
- * the number of apqns stored into the list is returned in *nr_apqns. One apqn
- * entry is simple a 32 bit value with 16 bit cardnr and 16 bit domain nr and
- * may be casted to struct pkey_apqn. The return value is either 0 for success
- * or a negative errno value. If no apqn meeting the criteria is found,
- * -ENODEV is returned.
+ * The caller should set *nr_apqns to the nr of elements available in *apqns.
+ * On return *nr_apqns is then updated with the nr of apqns filled into *apqns.
+ * The return value is either 0 for success or a negative errno value.
+ * If no apqn meeting the criteria is found, -ENODEV is returned.
  */
-int ep11_findcard2(u32 **apqns, u32 *nr_apqns, u16 cardnr, u16 domain,
+int ep11_findcard2(u32 *apqns, u32 *nr_apqns, u16 cardnr, u16 domain,
 		   int minhwtype, int minapi, const u8 *wkvp);
 
 /*
-- 
2.43.0