linux-kernel - [PATCH] mtd: cfi: use struct_size() helper for cfiq allocation

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Message-ID: <20250918184420.76047-1-krishnagopi487@gmail.com>
Date: Fri, 19 Sep 2025 00:14:14 +0530
From: Gopi Krishna Menon <krishnagopi487@...il.com>
To: miquel.raynal@...tlin.com,
	richard@....at,
	vigneshr@...com
Cc: Gopi Krishna Menon <krishnagopi487@...il.com>,
	linux-mtd@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	skhan@...uxfoundation.org,
	david.hunter.linux@...il.com,
	linux-kernel-mentees@...ts.linux.dev
Subject: [PATCH] mtd: cfi: use struct_size() helper for cfiq allocation

Documentation/process/deprecated.rst recommends against performing
dynamic size calculations in the arguments of memory allocator
function due to the risk of overflow. Such calculations can
wrap around and result in a smaller allocation than what the caller
was expecting.

Replace the size calculation in cfiq allocation with struct_size()
helper to make the code clearer and handle the overflows correctly.

Signed-off-by: Gopi Krishna Menon <krishnagopi487@...il.com>
---
 drivers/mtd/chips/cfi_probe.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mtd/chips/cfi_probe.c b/drivers/mtd/chips/cfi_probe.c
index a04b6174181c..e254f9cd2796 100644
--- a/drivers/mtd/chips/cfi_probe.c
+++ b/drivers/mtd/chips/cfi_probe.c
@@ -208,7 +208,7 @@ static int __xipram cfi_chip_setup(struct map_info *map,
 	if (!num_erase_regions)
 		return 0;
 
-	cfi->cfiq = kmalloc(sizeof(struct cfi_ident) + num_erase_regions * 4, GFP_KERNEL);
+	cfi->cfiq = kmalloc(struct_size(cfi->cfiq, EraseRegionInfo, num_erase_regions), GFP_KERNEL);
 	if (!cfi->cfiq)
 		return 0;
 
-- 
2.43.0