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

Harald Freudenberger
2025-03-04T17:21:32Z

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