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[92.21.50.228]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-493be4540aesm63473575e9.0.2026.07.01.02.41.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 01 Jul 2026 02:41:55 -0700 (PDT) Date: Tue, 30 Jun 2026 18:38:10 +0100 From: David Laight To: Thorsten Blum Cc: Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , "Christophe Leroy (CS GROUP)" , linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] powerpc/dt_cpu_ftrs: Avoid separate strlen() in scan_callback() Message-ID: <20260630183810.3287d10d@pumpkin> In-Reply-To: <20260630154657.693088-2-thorsten.blum@linux.dev> References: <20260630154657.693088-2-thorsten.blum@linux.dev> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; arm-unknown-linux-gnueabihf) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Tue, 30 Jun 2026 17:46:56 +0200 Thorsten Blum wrote: > Use the return value of strscpy() when copying the display name instead > of checking the source string length with strlen() first. > > Keep dt_cpu_name static but move it into dt_cpu_ftrs_scan_callback(), > where it is assigned. > > Signed-off-by: Thorsten Blum > --- > arch/powerpc/kernel/dt_cpu_ftrs.c | 7 ++----- > 1 file changed, 2 insertions(+), 5 deletions(-) > > diff --git a/arch/powerpc/kernel/dt_cpu_ftrs.c b/arch/powerpc/kernel/dt_cpu_ftrs.c > index 3af6c06af02f..8d8e94e4d2bc 100644 > --- a/arch/powerpc/kernel/dt_cpu_ftrs.c > +++ b/arch/powerpc/kernel/dt_cpu_ftrs.c > @@ -90,8 +90,6 @@ static void __restore_cpu_cpufeatures(void) > init_pmu_registers(); > } > > -static char dt_cpu_name[64]; > - > static struct cpu_spec __initdata base_cpu_spec = { > .cpu_name = NULL, > .cpu_features = CPU_FTRS_DT_CPU_BASE, > @@ -1069,6 +1067,7 @@ static int __init count_cpufeatures_subnodes(unsigned long node, > static int __init dt_cpu_ftrs_scan_callback(unsigned long node, const char > *uname, int depth, void *data) > { > + static char dt_cpu_name[64]; > const __be32 *prop; > int count, i; > u32 isa; > @@ -1106,10 +1105,8 @@ static int __init dt_cpu_ftrs_scan_callback(unsigned long node, const char > } > > prop = of_get_flat_dt_prop(node, "display-name", NULL); > - if (prop && strlen((char *)prop) != 0) { > - strscpy(dt_cpu_name, (char *)prop, sizeof(dt_cpu_name)); > + if (prop && strscpy(dt_cpu_name, (char *)prop) != 0) That is different code. The old code only did the copy if the new string was non-empty. So you want to replace the strlen() with *(char *)prop != 0. Checks for strlen() == 0 are silly (but surprisingly common). A search might show up this gem: str[strlen(str)] = 0; -- David > cur_cpu_spec->cpu_name = dt_cpu_name; > - } > > cpufeatures_setup_finished(); > >