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From: David Laight <David.Laight@ACULAB.COM>
To: 'Peng Zhang' <zhangpeng.00@bytedance.com>,
	Gang Li <ligang.bdlg@bytedance.com>
Cc: "akpm@linux-foundation.org" <akpm@linux-foundation.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"maple-tree@lists.infradead.org" <maple-tree@lists.infradead.org>,
	David Binderman <dcb314@hotmail.com>
Subject: RE: [PATCH] maple_tree: Use correct variable type in sizeof
Date: Tue, 11 Apr 2023 10:16:41 +0000	[thread overview]
Message-ID: <4211c1ee2b854711b9ff03ddd8e82905@AcuMS.aculab.com> (raw)
In-Reply-To: <b1ea2c08-8e88-e04f-417b-4cf0daa417b1@bytedance.com>

From: Peng Zhang
> Sent: 10 April 2023 11:09
> 
> 在 2023/4/10 17:46, Gang Li 写道:
> > On 2023/4/10 17:14, Peng Zhang wrote:
> >> The original code is:
> >>     memset(pivs + tmp, 0, sizeof(unsigned long *) * (max_p - tmp));
> >>
> >> The type of variable pointed to by pivs is unsigned long, but the type
> >> used in sizeof is a pointer type. Change it to unsigned long.
> >>
> >
> > Maybe add a fix tag?
> >
> > Fixes: 54a611b60590 ("Maple Tree: add new data structure")
> 
> Maybe sizeof(void *) is equal to sizeof(unsigned long)
> in most architectures, so I don't know if it counts as a fix.

Might be worth adding; "Fortunately the sizes are the same."

> >>             if (tmp < max_p)
> >>               memset(pivs + tmp, 0,
> >> -                   sizeof(unsigned long *) * (max_p - tmp));
> >> +                   sizeof(unsigned long) * (max_p - tmp));
	sizeof (*pivs)

> >>             if (tmp < mt_slots[mt])
> >>               memset(slots + tmp, 0, sizeof(void *) * (max_s - tmp));
	and sizeof (*slots)


	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)

  parent reply	other threads:[~2023-04-11 10:16 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-04-10  9:14 Peng Zhang
2023-04-10  9:46 ` Gang Li
2023-04-10 10:09   ` Peng Zhang
2023-04-10 13:51     ` Matthew Wilcox
2023-04-11 10:16     ` David Laight [this message]
2023-04-10 12:58 ` Liam R. Howlett

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