From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4787114B945; Mon, 14 Apr 2025 11:14:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744629298; cv=none; b=HJmItzj3nQQjQMSABP+eBsU7gK6OhnZC2XYaRgv2ZeLUpc6hwaCGwrOIiS/GuF5EXLoBstke1OUkkP2breb6G6VqVfDZv+UOmesDuZUl0h40v7WXqgU0IanLlWDhKdisHb0Myz2xCLgYWXQX/io6WcSXAdHtuJUMDTZ+cLqEM/g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744629298; c=relaxed/simple; bh=flJqvMobFZh3FwTRoPTH/ez/ycrQSv+CBOYXYJORcwY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=dBtA+3q3tT4pXLLqee1IvEK8gMm7Ig4pf/BY9W56gJdraDNHm9/+oM1s0yC6wB02KU73Sgh5XQ4hx6cI3vbUWHlrkYcbGlXHTnzI1UelEJVdSbdo9GIgVTRoWoi/rBch12oVl5zDha5fQ6ySZe5daRbb7YBZd1DtShIX6tW980c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=ImWuw5to; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="ImWuw5to" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=lA6D4wDYrR943Y2TW0Vrd2a63WSSLIFuyBx8vVO5YVE=; b=ImWuw5ton6/yrgizFFj3QaX8v5 7K57dEB4sx1+BYkDJYezdEJDy9qEUJHkVC6ikkbeGHhQUeGxG+awz5Gnnr8+iDUS23nUyawWwQFvG gWTqjhlupO+6xVnm4W0vI6OlvF+tsGWLuK7AGOAauk+8VnhkLixA7Z1EQcKoArBNlG5fPqR6gQ31w 6Z7Rd2ugyioYNo1wEW33zosyZPDXCuw5ULELZfaRCWVGep3hlRzD+CtLi2r9gq1z601cp6hQRZ2AS f0VqlUqhJEIGRC7i3m1qFUz93vdO6/ve0HxaeZUuVWgX3aiT0XLnLiF3XjN/mzvrifAiY1loyxFJs agw4J5Bg==; Received: from hch by bombadil.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1u4HmB-00000001iLS-2PsR; Mon, 14 Apr 2025 11:14:55 +0000 Date: Mon, 14 Apr 2025 04:14:55 -0700 From: Christoph Hellwig To: Balbir Singh Cc: iommu@lists.linux.dev, linux-kernel@vger.kernel.org, Marek Szyprowski , Robin Murphy , Christian =?iso-8859-1?Q?K=F6nig?= , Ingo Molnar , Kees Cook , Bjorn Helgaas , Linus Torvalds , Peter Zijlstra , Andy Lutomirski , Alex Deucher , Bert Karwatzki , Christoph Hellwig Subject: Re: [PATCH] dma/mapping.c: dev_dbg support for dma_addressing_limited Message-ID: References: <20250414110647.3294017-1-balbirs@nvidia.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250414110647.3294017-1-balbirs@nvidia.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Mon, Apr 14, 2025 at 09:06:46PM +1000, Balbir Singh wrote: > + dev_dbg(dev, "might have lower perf due to bounce buffering\n"); I don't think that's a good message. Report the actual observation, i.e. "device is DMA addressing limited" and not a guessed conclusion.