Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Arnd Bergmann <arnd@kernel.org>
To:     Miquel Raynal <miquel.raynal@bootlin.com>,
        Richard Weinberger <richard@nod.at>,
        Vignesh Raghavendra <vigneshr@ti.com>,
        =?UTF-8?q?Micha=C5=82=20K=C4=99pie=C5=84?= <kernel@kempniu.pl>
Cc:     Arnd Bergmann <arnd@arndb.de>, linux-mtd@lists.infradead.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH] mtdchar: mark bits of ioctl handler noinline
Date:   Mon, 17 Apr 2023 22:56:50 +0200
Message-Id: <20230417205654.1982368-1-arnd@kernel.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Arnd Bergmann <arnd@arndb.de>

The addition of the mtdchar_read_ioctl() function caused the stack usage
of mtdchar_ioctl() to grow beyond the warning limit on 32-bit architectures
with gcc-13:

drivers/mtd/mtdchar.c: In function 'mtdchar_ioctl':
drivers/mtd/mtdchar.c:1229:1: error: the frame size of 1488 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]

Mark both the read and write portions as noinline_for_stack to ensure
they don't get inlined and use separate stack slots to reduce the
maximum usage, both in the mtdchar_ioctl() and combined with any
of its callees.

Fixes: 095bb6e44eb1 ("mtdchar: add MEMREAD ioctl")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/mtd/mtdchar.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c
index 01f1c6792df9..8dc4f5c493fc 100644
--- a/drivers/mtd/mtdchar.c
+++ b/drivers/mtd/mtdchar.c
@@ -590,8 +590,8 @@ static void adjust_oob_length(struct mtd_info *mtd, uint64_t start,
 			    (end_page - start_page + 1) * oob_per_page);
 }
 
-static int mtdchar_write_ioctl(struct mtd_info *mtd,
-		struct mtd_write_req __user *argp)
+static noinline_for_stack int
+mtdchar_write_ioctl(struct mtd_info *mtd, struct mtd_write_req __user *argp)
 {
 	struct mtd_info *master = mtd_get_master(mtd);
 	struct mtd_write_req req;
@@ -688,8 +688,8 @@ static int mtdchar_write_ioctl(struct mtd_info *mtd,
 	return ret;
 }
 
-static int mtdchar_read_ioctl(struct mtd_info *mtd,
-		struct mtd_read_req __user *argp)
+static noinline_for_stack int
+mtdchar_read_ioctl(struct mtd_info *mtd, struct mtd_read_req __user *argp)
 {
 	struct mtd_info *master = mtd_get_master(mtd);
 	struct mtd_read_req req;
-- 
2.39.2