linux-kernel - [PATCH] staging: greybus: Remove unnecessary NUL-termination checks

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Message-ID: <20250331183935.1880097-2-thorsten.blum@linux.dev>
Date: Mon, 31 Mar 2025 20:39:35 +0200
From: Thorsten Blum <thorsten.blum@...ux.dev>
To: Viresh Kumar <vireshk@...nel.org>,
	Johan Hovold <johan@...nel.org>,
	Alex Elder <elder@...nel.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: Thorsten Blum <thorsten.blum@...ux.dev>,
	greybus-dev@...ts.linaro.org,
	linux-staging@...ts.linux.dev,
	linux-kernel@...r.kernel.org
Subject: [PATCH] staging: greybus: Remove unnecessary NUL-termination checks

Commit 18f44de63f88 ("staging: greybus: change strncpy() to
strscpy_pad()") didn't remove the now unnecessary NUL-termination
checks. Unlike strncpy(), strscpy_pad() guarantees that the destination
buffer is NUL-terminated, making the checks obsolete. Remove them.

Signed-off-by: Thorsten Blum <thorsten.blum@...ux.dev>
---
 drivers/staging/greybus/fw-management.c | 39 +------------------------
 1 file changed, 1 insertion(+), 38 deletions(-)

diff --git a/drivers/staging/greybus/fw-management.c b/drivers/staging/greybus/fw-management.c
index a47385175582..852c0830261f 100644
--- a/drivers/staging/greybus/fw-management.c
+++ b/drivers/staging/greybus/fw-management.c
@@ -125,16 +125,6 @@ static int fw_mgmt_interface_fw_version_operation(struct fw_mgmt *fw_mgmt,
 
 	strscpy_pad(fw_info->firmware_tag, response.firmware_tag);
 
-	/*
-	 * The firmware-tag should be NULL terminated, otherwise throw error but
-	 * don't fail.
-	 */
-	if (fw_info->firmware_tag[GB_FIRMWARE_TAG_MAX_SIZE - 1] != '\0') {
-		dev_err(fw_mgmt->parent,
-			"fw-version: firmware-tag is not NULL terminated\n");
-		fw_info->firmware_tag[GB_FIRMWARE_TAG_MAX_SIZE - 1] = '\0';
-	}
-
 	return 0;
 }
 
@@ -154,15 +144,6 @@ static int fw_mgmt_load_and_validate_operation(struct fw_mgmt *fw_mgmt,
 	request.load_method = load_method;
 	strscpy_pad(request.firmware_tag, tag);
 
-	/*
-	 * The firmware-tag should be NULL terminated, otherwise throw error and
-	 * fail.
-	 */
-	if (request.firmware_tag[GB_FIRMWARE_TAG_MAX_SIZE - 1] != '\0') {
-		dev_err(fw_mgmt->parent, "load-and-validate: firmware-tag is not NULL terminated\n");
-		return -EINVAL;
-	}
-
 	/* Allocate ids from 1 to 255 (u8-max), 0 is an invalid id */
 	ret = ida_alloc_range(&fw_mgmt->id_map, 1, 255, GFP_KERNEL);
 	if (ret < 0) {
@@ -250,15 +231,6 @@ static int fw_mgmt_backend_fw_version_operation(struct fw_mgmt *fw_mgmt,
 
 	strscpy_pad(request.firmware_tag, fw_info->firmware_tag);
 
-	/*
-	 * The firmware-tag should be NULL terminated, otherwise throw error and
-	 * fail.
-	 */
-	if (request.firmware_tag[GB_FIRMWARE_TAG_MAX_SIZE - 1] != '\0') {
-		dev_err(fw_mgmt->parent, "backend-version: firmware-tag is not NULL terminated\n");
-		return -EINVAL;
-	}
-
 	ret = gb_operation_sync(connection,
 				GB_FW_MGMT_TYPE_BACKEND_FW_VERSION, &request,
 				sizeof(request), &response, sizeof(response));
@@ -301,16 +273,7 @@ static int fw_mgmt_backend_fw_update_operation(struct fw_mgmt *fw_mgmt,
 	struct gb_fw_mgmt_backend_fw_update_request request;
 	int ret;
 
-	ret = strscpy_pad(request.firmware_tag, tag);
-
-	/*
-	 * The firmware-tag should be NULL terminated, otherwise throw error and
-	 * fail.
-	 */
-	if (ret == -E2BIG) {
-		dev_err(fw_mgmt->parent, "backend-update: firmware-tag is not NULL terminated\n");
-		return -EINVAL;
-	}
+	strscpy_pad(request.firmware_tag, tag);
 
 	/* Allocate ids from 1 to 255 (u8-max), 0 is an invalid id */
 	ret = ida_alloc_range(&fw_mgmt->id_map, 1, 255, GFP_KERNEL);