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Subject: Re: [patch 02/13] jffs2 summary allocation: don't use vmalloc()
From: Artem Bityutskiy <dedekind@infradead.org>
To: David Brownell <david-b@pacbell.net>
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Date: Thu, 31 Jul 2008 08:37:41 +0300
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Cc: linux-mtd@lists.infradead.org, trimarchimichael@yahoo.it,
	Andrew Morton <akpm@linux-foundation.org>, dwmw2@infradead.org,
	jwboyer@gmail.com, rmk@arm.linux.org.uk
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On Wed, 2008-07-30 at 22:10 -0700, David Brownell wrote:
> -	int (*read) (struct mtd_info *mtd, loff_t from, size_t len, size_t *ret=
len, u_char *buf);
> -	int (*write) (struct mtd_info *mtd, loff_t to, size_t len, size_t *retl=
en, const u_char *buf);
> +	/*
> +	 * Read/write operations are given *VIRTUAL* addresses, which
> +	 * must not be passed as-is to dma mapping operations.
> +	 */
> +	int (*read) (struct mtd_info *mtd, loff_t from,
> +			size_t len, size_t *retlen, u_char *virt);
> +	int (*write) (struct mtd_info *mtd, loff_t to,
> +			size_t len, size_t *retlen, const u_char *virt);
> =20
>  	/* In blackbox flight recorder like scenarios we want to make successfu=
l
>  	   writes in interrupt context. panic_write() is only intended to be

Can SPI driver detect if the memory was kmalloc()'ed or vmalloc()'ed? Or
if not, we could add one more argument to read()/write() which tells
whether the memory is contiguous or not. Then the driver would chose how
to deal with the buffer.

--=20
Best regards,
Artem Bityutskiy (=D0=91=D0=B8=D1=82=D1=8E=D1=86=D0=BA=D0=B8=D0=B9 =D0=90=
=D1=80=D1=82=D1=91=D0=BC)