crypto: nx - Fix uninitialised hv_nxc on error

The compiler correctly warns that hv_nxc may be used uninitialised
as that will occur when NX-GZIP is unavailable.

Fix it by rearranging the code and delay setting caps_feat until
the final query succeeds.

Fixes: b4ba221 ("crypto/nx: Get NX capabilities for GZIP coprocessor type")
Signed-off-by: Herbert Xu <[email protected]>

Author: herbertx

drivers/crypto/nx/nx-common-pseries.c

@@ -1145,6 +1145,7 @@ static void __init nxcop_get_capabilities(void)
 {
 	struct hv_vas_all_caps *hv_caps;
 	struct hv_nx_cop_caps *hv_nxc;
+	u64 feat;
 	int rc;
 
 	hv_caps = kmalloc(sizeof(*hv_caps), GFP_KERNEL);
@@ -1155,27 +1156,26 @@ static void __init nxcop_get_capabilities(void)
 	 */
 	rc = h_query_vas_capabilities(H_QUERY_NX_CAPABILITIES, 0,
 					  (u64)virt_to_phys(hv_caps));
+	if (!rc)
+		feat = be64_to_cpu(hv_caps->feat_type);
+	kfree(hv_caps);
 	if (rc)
-		goto out;
+		return;
+	if (!(feat & VAS_NX_GZIP_FEAT_BIT))
+		return;
 
-	caps_feat = be64_to_cpu(hv_caps->feat_type);
 	/*
 	 * NX-GZIP feature available
 	 */
-	if (caps_feat & VAS_NX_GZIP_FEAT_BIT) {
-		hv_nxc = kmalloc(sizeof(*hv_nxc), GFP_KERNEL);
-		if (!hv_nxc)
-			goto out;
-		/*
-		 * Get capabilities for NX-GZIP feature
-		 */
-		rc = h_query_vas_capabilities(H_QUERY_NX_CAPABILITIES,
-						  VAS_NX_GZIP_FEAT,
-						  (u64)virt_to_phys(hv_nxc));
-	} else {
-		pr_err("NX-GZIP feature is not available\n");
-		rc = -EINVAL;
-	}
+	hv_nxc = kmalloc(sizeof(*hv_nxc), GFP_KERNEL);
+	if (!hv_nxc)
+		return;
+	/*
+	 * Get capabilities for NX-GZIP feature
+	 */
+	rc = h_query_vas_capabilities(H_QUERY_NX_CAPABILITIES,
+					  VAS_NX_GZIP_FEAT,
+					  (u64)virt_to_phys(hv_nxc));
 
 	if (!rc) {
 		nx_cop_caps.descriptor = be64_to_cpu(hv_nxc->descriptor);
@@ -1185,13 +1185,10 @@ static void __init nxcop_get_capabilities(void)
 				be64_to_cpu(hv_nxc->min_compress_len);
 		nx_cop_caps.min_decompress_len =
 				be64_to_cpu(hv_nxc->min_decompress_len);
-	} else {
-		caps_feat = 0;
+		caps_feat = feat;
 	}
 
 	kfree(hv_nxc);
-out:
-	kfree(hv_caps);
 }
 
 static const struct vio_device_id nx842_vio_driver_ids[] = {