From: Andrew Morton <akpm@linux-foundation.org>
To: Thorsten Blum <thorsten.blum@linux.dev>
Cc: Kees Cook <kees@kernel.org>, Andy Shevchenko <andy@kernel.org>,
linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
Subject: Re: [PATCH] string: use min in sized_strscpy
Date: Tue, 19 May 2026 12:37:40 -0700 [thread overview]
Message-ID: <20260519123740.458d905f958f39d41cb130fd@linux-foundation.org> (raw)
In-Reply-To: <20260514165601.527883-3-thorsten.blum@linux.dev>
On Thu, 14 May 2026 18:56:03 +0200 Thorsten Blum <thorsten.blum@linux.dev> wrote:
> Use min() and drop the limit variable to simplify sized_strscpy().
Why is this code so messy. Never seen so many typecasts per inch.
> @@ -125,11 +126,8 @@ ssize_t sized_strscpy(char *dest, const char *src, size_t count)
> * If src is unaligned, don't cross a page boundary,
> * since we don't know if the next page is mapped.
> */
> - if ((long)src & (sizeof(long) - 1)) {
> - size_t limit = PAGE_SIZE - ((long)src & (PAGE_SIZE - 1));
> - if (limit < max)
> - max = limit;
> - }
> + if ((long)src & (sizeof(long) - 1))
That looks like IS_ALIGNED()?
> + max = min(PAGE_SIZE - ((long)src & (PAGE_SIZE - 1)), max);
That looks like a dog's breakfast.
And a bit like ALIGN_DOWN. Not quite, but I'm sure we have helpers for
whatever this is doing.
> #else
> /* If src or dest is unaligned, don't do word-at-a-time. */
> if (((long) dest | (long) src) & (sizeof(long) - 1))
gargh.
Oh well, not your fault. I'll grab the patch, thanks.
prev parent reply other threads:[~2026-05-19 19:37 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-14 16:56 [PATCH] string: use min in sized_strscpy Thorsten Blum
2026-05-15 6:45 ` Andy Shevchenko
2026-05-15 15:09 ` Thorsten Blum
2026-05-17 5:56 ` Andy Shevchenko
2026-05-17 14:14 ` David Laight
2026-05-19 19:37 ` Andrew Morton [this message]
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