crypto: nx - prevent nx 842 load if no hw driver

Change the nx-842 common driver to wait for loading of both platform
drivers, and fail loading if the platform driver pointer is not set.
Add an independent platform driver pointer, that the platform drivers
set if they find they are able to load (i.e. if they find their platform
devicetree node(s)).

The problem is currently, the main nx-842 driver will stay loaded even
if there is no platform driver and thus no possible way it can do any
compression or decompression.  This allows the crypto 842-nx driver
to load even if it won't actually work.  For crypto compression users
(e.g. zswap) that expect an available crypto compression driver to
actually work, this is bad.  This patch fixes that, so the 842-nx crypto
compression driver won't load if it doesn't have the driver and hardware
available to perform the compression.

Signed-off-by: Dan Streetman <ddstreet@ieee.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 13 insertions, 4 deletions

diff --git a/drivers/crypto/nx/nx-842-powernv.c b/drivers/crypto/nx/nx-842-powernv.c
index 6a9fb8b2d05b..c388dba7da64 100644
--- a/drivers/crypto/nx/nx-842-powernv.c
+++ b/drivers/crypto/nx/nx-842-powernv.c
@@ -23,7 +23,6 @@
 #include <asm/prom.h>
 #include <asm/icswx.h>
 
-#define MODULE_NAME NX842_POWERNV_MODULE_NAME
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Dan Streetman <ddstreet@ieee.org>");
 MODULE_DESCRIPTION("842 H/W Compression driver for IBM PowerNV processors");
@@ -571,6 +570,7 @@ static struct nx842_constraints nx842_powernv_constraints = {
 };
 
 static struct nx842_driver nx842_powernv_driver = {
+	.name =		KBUILD_MODNAME,
 	.owner =	THIS_MODULE,
 	.constraints =	&nx842_powernv_constraints,
 	.compress =	nx842_powernv_compress,
@@ -593,7 +593,7 @@ static __init int nx842_powernv_init(void)
 
 	pr_info("loading\n");
 
-	for_each_compatible_node(dn, NULL, NX842_POWERNV_COMPAT_NAME)
+	for_each_compatible_node(dn, NULL, "ibm,power-nx")
 		nx842_powernv_probe(dn);
 
 	if (!nx842_ct) {
@@ -601,7 +601,16 @@ static __init int nx842_powernv_init(void)
 		return -ENODEV;
 	}
 
-	nx842_register_driver(&nx842_powernv_driver);
+	if (!nx842_platform_driver_set(&nx842_powernv_driver)) {
+		struct nx842_coproc *coproc, *n;
+
+		list_for_each_entry_safe(coproc, n, &nx842_coprocs, list) {
+			list_del(&coproc->list);
+			kfree(coproc);
+		}
+
+		return -EEXIST;
+	}
 
 	pr_info("loaded\n");
 
@@ -613,7 +622,7 @@ static void __exit nx842_powernv_exit(void)
 {
 	struct nx842_coproc *coproc, *n;
 
-	nx842_unregister_driver(&nx842_powernv_driver);
+	nx842_platform_driver_unset(&nx842_powernv_driver);
 
 	list_for_each_entry_safe(coproc, n, &nx842_coprocs, list) {
 		list_del(&coproc->list);