[PATCH v2 16/20] s390/zcrypt: Add small mempool for ep11 card info list entries

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

Add a small memory pool for (pre-)allocating ep11 card info list
entries. These entries are rather small and the pool is a simple
way to support the xflag ZCRYPT_XFLAG_NOMEMALLOC to avoid mallocs.

Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
---
 drivers/s390/crypto/zcrypt_ep11misc.c | 48 ++++++++++++++++++++++-----
 1 file changed, 39 insertions(+), 9 deletions(-)

diff --git a/drivers/s390/crypto/zcrypt_ep11misc.c b/drivers/s390/crypto/zcrypt_ep11misc.c
index af59d66bff33..a9a6fdc32464 100644
--- a/drivers/s390/crypto/zcrypt_ep11misc.c
+++ b/drivers/s390/crypto/zcrypt_ep11misc.c
@@ -64,6 +64,10 @@ struct card_list_entry {
 static LIST_HEAD(card_list);
 static DEFINE_SPINLOCK(card_list_lock);
 
+/* memory pool for card_list_entry entries */
+#define INFO_ENTRY_MEMPOOL_MIN_ITEMS 4
+static mempool_t *info_mempool;
+
 static int card_cache_fetch(u16 cardnr, struct ep11_card_info *ci)
 {
 	int rc = -ENOENT;
@@ -82,7 +86,8 @@ static int card_cache_fetch(u16 cardnr, struct ep11_card_info *ci)
 	return rc;
 }
 
-static void card_cache_update(u16 cardnr, const struct ep11_card_info *ci)
+static void card_cache_update(u16 cardnr, const struct ep11_card_info *ci,
+			      u32 xflags)
 {
 	int found = 0;
 	struct card_list_entry *ptr;
@@ -96,7 +101,9 @@ static void card_cache_update(u16 cardnr, const struct ep11_card_info *ci)
 		}
 	}
 	if (!found) {
-		ptr = kmalloc(sizeof(*ptr), GFP_ATOMIC);
+		ptr = (xflags & ZCRYPT_XFLAG_NOMEMALLOC) ?
+			mempool_alloc_preallocated(info_mempool) :
+			mempool_alloc(info_mempool, GFP_ATOMIC);
 		if (!ptr) {
 			spin_unlock_bh(&card_list_lock);
 			return;
@@ -116,7 +123,7 @@ static void card_cache_scrub(u16 cardnr)
 	list_for_each_entry(ptr, &card_list, list) {
 		if (ptr->cardnr == cardnr) {
 			list_del(&ptr->list);
-			kfree(ptr);
+			mempool_free(ptr, info_mempool);
 			break;
 		}
 	}
@@ -130,7 +137,7 @@ static void __exit card_cache_free(void)
 	spin_lock_bh(&card_list_lock);
 	list_for_each_entry_safe(ptr, pnext, &card_list, list) {
 		list_del(&ptr->list);
-		kfree(ptr);
+		mempool_free(ptr, info_mempool);
 	}
 	spin_unlock_bh(&card_list_lock);
 }
@@ -772,7 +779,7 @@ int ep11_get_card_info(u16 card, struct ep11_card_info *info,
 			(pmqi->FW_major_vers << 8) + pmqi->FW_minor_vers;
 		memcpy(info->serial, pmqi->serial, sizeof(info->serial));
 		info->op_mode = pmqi->op_mode;
-		card_cache_update(card, info);
+		card_cache_update(card, info, xflags);
 	}
 
 out:
@@ -1713,6 +1720,8 @@ EXPORT_SYMBOL(ep11_findcard2);
 
 int __init zcrypt_ep11misc_init(void)
 {
+	int rc = -ENOMEM;
+
 	/* Pre-allocate a small memory pool for ep11 cprbs. */
 	cprb_mempool = mempool_create_kmalloc_pool(zcrypt_ep11_cprbpool_min_items,
 						   CPRB_MEMPOOL_ITEM_SIZE);
@@ -1720,19 +1729,39 @@ int __init zcrypt_ep11misc_init(void)
 		ZCRYPT_DBF_ERR("%s mempool_create(%d,%d) failed: %ld\n",
 			       __func__, zcrypt_ep11_cprbpool_min_items,
 			       CPRB_MEMPOOL_ITEM_SIZE, PTR_ERR(cprb_mempool));
+		rc = PTR_ERR(cprb_mempool);
 		cprb_mempool = NULL;
-		return -ENOMEM;
+		goto out;
+	}
+
+	/* Pre-allocate a very small memory pool for card info entries */
+	info_mempool = mempool_create_kmalloc_pool(INFO_ENTRY_MEMPOOL_MIN_ITEMS,
+						   sizeof(struct card_list_entry));
+	if (IS_ERR(info_mempool)) {
+		ZCRYPT_DBF_ERR("%s card info entry mempool_create(%d,%d) failed: %ld\n",
+			       __func__, INFO_ENTRY_MEMPOOL_MIN_ITEMS,
+			       (int)sizeof(struct card_list_entry),
+			       PTR_ERR(info_mempool));
+		rc = PTR_ERR(info_mempool);
+		info_mempool = NULL;
+		goto out;
 	}
 
 	/* Pre-allocate one crypto status card struct used in findcard() */
 	dev_status_mem = kvmalloc(ZCRYPT_DEV_STATUS_EXT_SIZE, GFP_KERNEL);
 	if (!dev_status_mem) {
 		ZCRYPT_DBF_ERR("%s allocation of dev_status_mem failed\n", __func__);
-		mempool_destroy(cprb_mempool);
-		return -ENOMEM;
+		goto out;
 	}
 
-	return 0;
+	rc = 0;
+
+out:
+	if (rc) {
+		mempool_destroy(cprb_mempool);
+		mempool_destroy(info_mempool);
+	}
+	return rc;
 }
 
 void zcrypt_ep11misc_exit(void)
@@ -1740,4 +1769,5 @@ void zcrypt_ep11misc_exit(void)
 	card_cache_free();
 	kvfree(dev_status_mem);
 	mempool_destroy(cprb_mempool);
+	mempool_destroy(info_mempool);
 }
-- 
2.43.0