s390/zcrypt: Rework cca misc functions kmallocs to use the cprb mempool

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>
Link: https://lore.kernel.org/r/20250424133619.16495-16-freude@linux.ibm.com
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

Author: hfreude

drivers/s390/crypto/zcrypt_ccamisc.c

@@ -1126,20 +1126,29 @@ 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);
 
@@ -1196,7 +1205,7 @@ 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);
@@ -1628,10 +1637,12 @@ EXPORT_SYMBOL(cca_query_crypto_facility);
  */
 int cca_get_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));
 
@@ -1641,12 +1652,17 @@ int cca_get_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 */
@@ -1693,7 +1709,7 @@ int cca_get_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;
 }
 EXPORT_SYMBOL(cca_get_info);