[PATCH RESEND] staging: nvec: use strcmp() instead of strncmp() with magic length

[PATCH RESEND] staging: nvec: use strcmp() instead of strncmp() with magic length

[Artem Lytkin]

Replace strncmp() with a hardcoded length of 30 with strcmp().
The bat_type string is already null-terminated (set two lines above),
so strncmp() with an arbitrary length is misleading and functionally
equivalent to strcmp().

Signed-off-by: Artem Lytkin <iprintercanon@gmail.com>
---
 drivers/staging/nvec/nvec_power.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/staging/nvec/nvec_power.c b/drivers/staging/nvec/nvec_power.c
index 2faab9fdedef7..89dd997aaf36b 100644
--- a/drivers/staging/nvec/nvec_power.c
+++ b/drivers/staging/nvec/nvec_power.c
@@ -207,7 +207,7 @@ static int nvec_power_bat_notifier(struct notifier_block *nb,
 		 * This differs a little from the spec fill in more if you find
 		 * some.
 		 */
-		if (!strncmp(power->bat_type, "Li", 30))
+		if (!strcmp(power->bat_type, "Li"))
 			power->bat_type_enum = POWER_SUPPLY_TECHNOLOGY_LION;
 		else
 			power->bat_type_enum = POWER_SUPPLY_TECHNOLOGY_UNKNOWN;
-- 
2.43.0

Re: [PATCH RESEND] staging: nvec: use strcmp() instead of strncmp() with magic length

[Thierry Reding]

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On Thu, Jul 23, 2026 at 07:18:23PM +0300, Artem Lytkin wrote:
> Replace strncmp() with a hardcoded length of 30 with strcmp().
> The bat_type string is already null-terminated (set two lines above),
> so strncmp() with an arbitrary length is misleading and functionally
> equivalent to strcmp().
> 
> Signed-off-by: Artem Lytkin <iprintercanon@gmail.com>
> ---
>  drivers/staging/nvec/nvec_power.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

I don't really see a point in this. strncmp() doesn't do any harm and it
isn't misleading either. It's just very explicit that it should never
check more than those 30 characters that can fit into the type string.

Technically res->length could be larger than 30, in which case the
memcpy() might copy more than those 30. Judging by the nvec core code we
never sanity check the length, so even that memcpy() could be entirely
wrong.

Either way, this change by itself doesn't look useful.

Thierry

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