From: Ard Biesheuvel <ardb@kernel.org>
Date: Mon, 20 Jun 2022 12:03:50 +0200
Subject: media: atomisp_gmin_platform: stop abusing efivar API
Patch-mainline: v6.0-rc1
Git-commit: 38d4f74bc14847491d07bd745dc4a2c274f4987d
References: jsc#PED-1409

As the code comment already suggests, using the efivar API in this way
is not how it is intended, and so let's switch to the right one, which
is simply to call efi.get_variable() directly after checking whether or
not the GetVariable() runtime service is supported.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Lee, Chun-Yi <jlee@suse.com>
---
 drivers/staging/media/atomisp/pci/atomisp_gmin_platform.c |   27 +++-----------
 1 file changed, 6 insertions(+), 21 deletions(-)

--- a/drivers/staging/media/atomisp/pci/atomisp_gmin_platform.c
+++ b/drivers/staging/media/atomisp/pci/atomisp_gmin_platform.c
@@ -1217,7 +1217,7 @@ static int gmin_get_config_var(struct de
 	const struct dmi_system_id *id;
 	struct device *dev = maindev;
 	char var8[CFG_VAR_NAME_MAX];
-	struct efivar_entry *ev;
+	efi_status_t status;
 	int i, ret;
 
 	/* For sensors, try first to use the _DSM table */
@@ -1259,24 +1259,11 @@ static int gmin_get_config_var(struct de
 	for (i = 0; i < sizeof(var8) && var8[i]; i++)
 		var16[i] = var8[i];
 
-	/* Not sure this API usage is kosher; efivar_entry_get()'s
-	 * implementation simply uses VariableName and VendorGuid from
-	 * the struct and ignores the rest, but it seems like there
-	 * ought to be an "official" efivar_entry registered
-	 * somewhere?
-	 */
-	ev = kzalloc(sizeof(*ev), GFP_KERNEL);
-	if (!ev)
-		return -ENOMEM;
-	memcpy(&ev->var.VariableName, var16, sizeof(var16));
-	ev->var.VendorGuid = GMIN_CFG_VAR_EFI_GUID;
-	ev->var.DataSize = *out_len;
-
-	ret = efivar_entry_get(ev, &ev->var.Attributes,
-			       &ev->var.DataSize, ev->var.Data);
-	if (ret == 0) {
-		memcpy(out, ev->var.Data, ev->var.DataSize);
-		*out_len = ev->var.DataSize;
+	status = EFI_UNSUPPORTED;
+	if (efi_rt_services_supported(EFI_RT_SUPPORTED_GET_VARIABLE))
+		status = efi.get_variable(var16, &GMIN_CFG_VAR_EFI_GUID, NULL,
+					  (unsigned long *)out_len, out);
+	if (status == EFI_SUCCESS) {
 		dev_info(maindev, "found EFI entry for '%s'\n", var8);
 	} else if (is_gmin) {
 		dev_info(maindev, "Failed to find EFI gmin variable %s\n", var8);
@@ -1284,8 +1271,6 @@ static int gmin_get_config_var(struct de
 		dev_info(maindev, "Failed to find EFI variable %s\n", var8);
 	}
 
-	kfree(ev);
-
 	return ret;
 }