[PATCH v4 15/24] s390/zcrypt: Rework cca misc functions kmallocs to use the cprb mempool

Harald Freudenberger
2025-04-09T14:03:23Z

Rework two places in the zcrypt cca misc code using kmalloc() for
ephemeral memory allocation. As there is anyway now a cprb mempool
let's use this pool instead to satisfy these short term memory
allocations.

Signed-off-by: Harald Freudenberger <freude@linux.ibm.com>
Reviewed-by: Holger Dengler <dengler@linux.ibm.com>
---
drivers/s390/crypto/zcrypt_ccamisc.c | 42 +++++++++++++++++++---------
1 file changed, 29 insertions(+), 13 deletions(-)

diff --git a/drivers/s390/crypto/zcrypt_ccamisc.c b/drivers/s390/crypto/zcrypt_ccamisc.c
index 15731eb250fb..88f3c7708c2a 100644
--- a/drivers/s390/crypto/zcrypt_ccamisc.c
+++ b/drivers/s390/crypto/zcrypt_ccamisc.c
@@ -1128,20 +1128,29 @@ int cca_clr2cipherkey(u16 card, u16 dom, u32 keybitsize, u32 keygenflags,
const u8 *clrkey, u8 *keybuf, u32 *keybufsize)
{
int rc;
- u8 *token;
+ void *mem;
int tokensize;
- u8 exorbuf[32];
+ u8 *token, exorbuf[32];
struct cipherkeytoken *t;
+ u32 xflags = 0;

/* fill exorbuf with random data */
get_random_bytes(exorbuf, sizeof(exorbuf));

- /* allocate space for the key token to build */
- token = kmalloc(MAXCCAVLSCTOKENSIZE, GFP_KERNEL);
- if (!token)
+ /*
+ * Allocate space for the key token to build.
+ * Also we only need up to MAXCCAVLSCTOKENSIZE bytes for this
+ * we use the already existing cprb mempool to solve this
+ * short term memory requirement.
+ */
+ mem = (xflags & ZCRYPT_XFLAG_NOMEMALLOC) ?
+ mempool_alloc_preallocated(cprb_mempool) :
+ mempool_alloc(cprb_mempool, GFP_KERNEL);
+ if (!mem)
return -ENOMEM;

/* prepare the token with the key skeleton */
+ token = (u8 *)mem;
tokensize = SIZEOF_SKELETON;
memcpy(token, aes_cipher_key_skeleton, tokensize);

@@ -1198,7 +1207,7 @@ int cca_clr2cipherkey(u16 card, u16 dom, u32 keybitsize, u32 keygenflags,
*keybufsize = tokensize;

out:
- kfree(token);
+ mempool_free(mem, cprb_mempool);
return rc;
}
EXPORT_SYMBOL(cca_clr2cipherkey);
@@ -1629,10 +1638,12 @@ EXPORT_SYMBOL(cca_query_crypto_facility);
*/
static int fetch_cca_info(u16 cardnr, u16 domain, struct cca_info *ci)
{
+ void *mem;
int rc, found = 0;
size_t rlen, vlen;
- u8 *rarray, *varray, *pg;
+ u8 *rarray, *varray;
struct zcrypt_device_status_ext devstat;
+ u32 xflags = 0;

memset(ci, 0, sizeof(*ci));

@@ -1642,12 +1653,17 @@ static int fetch_cca_info(u16 cardnr, u16 domain, struct cca_info *ci)
return rc;
ci->hwtype = devstat.hwtype;

- /* prep page for rule array and var array use */
- pg = (u8 *)__get_free_page(GFP_KERNEL);
- if (!pg)
+ /*
+ * Prep memory for rule array and var array use.
+ * Use the cprb mempool for this.
+ */
+ mem = (xflags & ZCRYPT_XFLAG_NOMEMALLOC) ?
+ mempool_alloc_preallocated(cprb_mempool) :
+ mempool_alloc(cprb_mempool, GFP_KERNEL);
+ if (!mem)
return -ENOMEM;
- rarray = pg;
- varray = pg + PAGE_SIZE / 2;
+ rarray = (u8 *)mem;
+ varray = (u8 *)mem + PAGE_SIZE / 2;
rlen = vlen = PAGE_SIZE / 2;

/* QF for this card/domain */
@@ -1694,7 +1710,7 @@ static int fetch_cca_info(u16 cardnr, u16 domain, struct cca_info *ci)
}

out:
- free_page((unsigned long)pg);
+ mempool_free(mem, cprb_mempool);
return found == 2 ? 0 : -ENOENT;
}

--
2.43.0