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Date:   Sat, 2 Sep 2023 06:30:44 +0100
From:   Al Viro <viro@zeniv.linux.org.uk>
To:     Takashi Iwai <tiwai@suse.de>
Cc:     alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 02/25] ALSA: pcm: Add copy ops with iov_iter
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 <20230815190136.8987-3-tiwai@suse.de>
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On Tue, Aug 15, 2023 at 09:01:13PM +0200, Takashi Iwai wrote:

> -	if (copy_from_user(get_dma_ptr(substream->runtime, channel, hwoff),
> -			   (void __user *)buf, bytes))
> +	if (!copy_from_iter(get_dma_ptr(substream->runtime, channel, hwoff),
> +			    bytes, iter))

The former is "if not everything got copied", the latter - "if nothing got
copied"; the same goes for other places like that.