From: Andreas Schwab <schwab@linux-m68k.org>
To: Nathan Chancellor <nathan@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>,
Thomas Gleixner <tglx@kernel.org>, Theodore Ts'o <tytso@mit.edu>,
"Jason A. Donenfeld" <Jason@zx2c4.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Nick Desaulniers <ndesaulniers@google.com>,
Bill Wendling <morbo@google.com>,
Justin Stitt <justinstitt@google.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Huacai Chen <chenhuacai@kernel.org>,
WANG Xuerui <kernel@xen0n.name>,
Madhavan Srinivasan <maddy@linux.ibm.com>,
Michael Ellerman <mpe@ellerman.id.au>,
Nicholas Piggin <npiggin@gmail.com>,
"Christophe Leroy (CS GROUP)" <chleroy@kernel.org>,
Paul Walmsley <pjw@kernel.org>,
Palmer Dabbelt <palmer@dabbelt.com>,
Albert Ou <aou@eecs.berkeley.edu>,
Alexandre Ghiti <alex@ghiti.fr>,
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Sven Schnelle <svens@linux.ibm.com>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, loongarch@lists.linux.dev,
linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org,
linux-s390@vger.kernel.org, llvm@lists.linux.dev
Subject: Re: [PATCH v2] random: vDSO: Avoid call to memset() when zeroing reserved in __cvdso_getrandom_data()
Date: Sat, 26 Sep 2026 11:39:43 +0200 [thread overview]
Message-ID: <87zex4ic68.fsf@linux-m68k.org> (raw)
In-Reply-To: <20260925-vdso-getrandom-avoid-memset-llvm-24-v2-1-ce640f872393@kernel.org>
On Sep 25 2026, Nathan Chancellor wrote:
> +#if __has_builtin(__builtin_memset_inline)
> +#define memset_inline(dst, value, size) __builtin_memset_inline(dst, value, size)
> +#elif IS_ENABLED(CONFIG_CC_HAS_OPT_INLINE_MEMSET)
> +#define memset_inline(dst, value, size) __builtin_memset(dst, value, size)
> +#else
> +static inline void *memset_inline(void *dst, int value, size_t size)
> +{
> + char *d = dst;
> +
> + while (size--)
> + *d++ = value;
> +
> + return d;
> +}
> +#endif
> +
memset actually returns the original pointer, not the incremented one.
Nothing uses the return value of memset_inline here, but it is
confusing.
--
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1
"And now for something completely different."
prev parent reply other threads:[~2026-09-26 9:48 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-25 21:46 Nathan Chancellor
2026-09-25 21:53 ` Nick Desaulniers
2026-09-25 21:56 ` Nick Desaulniers
2026-09-25 22:00 ` Nick Desaulniers
2026-09-25 22:19 ` Nathan Chancellor
2026-09-26 6:34 ` Christophe Leroy (CS GROUP)
2026-09-26 10:02 ` Jason A. Donenfeld
2026-09-26 9:39 ` Andreas Schwab [this message]
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