From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 48F4838E119; Fri, 2 Oct 2026 15:34:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790955241; cv=none; b=cD3YrAxvOTZTpbIYd0JY/euKn3DBi6WSWyExKa2arifn4X/TipBj4XzyqFAt4e9CvA300RA8LiHglJWVXS9PpLuXGh1UlQwgxFYjR0JUymy8tpkz6ZH8Cb/7qC1kpl778OPrV8TFmq03hoRmA1ghqQ9kXZmsaITzX1JTs8zzrtk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790955241; c=relaxed/simple; bh=Jf9Y3k5GT8BZYKjOKfODxcpt0k4pXZxOKwZRsxr9uVc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ano5ky2a23kA6GlkL7dcfMQq+vmBr9glGyp7vqYQknpHbf8WiRDAq6U1In2xWVozHpp8C0Xd+rqTnrIK87VSThARpY1sbIVaKcyUgPopUKKVbiFPoMledNVY/M8OWo0l7GkQUcwxzA5zFuLUm1iouWry/uXOeuViElgcfIKdDso= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=XWjFqyFh; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="XWjFqyFh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8B48C1F000FF; Fri, 2 Oct 2026 15:33:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790955239; bh=BBvnzeVp5FHZbtbBZ742DHLscz+VvjPcvOwODIGv8pw=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=XWjFqyFh/EG972dwRFuGfXIxWJ8hldbJMvx9UV/6AREZaqE4lrtN1YXaUywZDdaHD Q2ZSH1eValsjSi+u84xNA3G4wHT8ZIfkCn49rQGHxQr4e3hpQOeqgPeu4agZj0xzJg LnJfRYjxBg/69Q8uhAeq13pk6Y1s8Al917oAsW3aN/WtN4MOKF3rlipnT/iHgIoe2p q+fuaNEtlo66Zx3gwEpj8AzbX0Lp+taf+9dhW7icW5HjQc9k7MXS9JgDI7oto7usjE RE+BzBk0gMlrnYIPp5M783xe34Yvwl73O/IWpIzpaQDIJdWPWaNWtufA+4PgCf8tYd FQvTq59FnAg5w== Date: Fri, 2 Oct 2026 16:33:52 +0100 From: Will Deacon To: Kiryl Shutsemau Cc: Jason Gunthorpe , Robin Murphy , Joerg Roedel , Nicolin Chen , Pranjal Shrivastava , Mostafa Saleh , Thierry Reding , Krishna Reddy , Jonathan Hunter , Breno Leitao , Kyle McMartin , Usama Arif , kernel-team@meta.com, linux-arm-kernel@lists.infradead.org, iommu@lists.linux.dev, linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v6 1/2] iommu/arm-smmu-v3: Add a cmdq_max_n_shift module parameter Message-ID: References: <20260909095228.2174031-1-kas@kernel.org> <20260909095228.2174031-2-kas@kernel.org> <179018301689.3334538.1783583175230817305.b4-review@b4> Precedence: bulk X-Mailing-List: linux-tegra@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: On Fri, Sep 25, 2026 at 11:01:31AM +0100, Kiryl Shutsemau wrote: > On Wed, Sep 23, 2026 at 02:03:36PM -0300, Jason Gunthorpe wrote: > > > [ ... 34 lines skipped ... ] > > > @@ -40,6 +40,11 @@ module_param(disable_msipolling, bool, 0444); > > > MODULE_PARM_DESC(disable_msipolling, > > > "Disable MSI-based polling for CMD_SYNC completion."); > > > > > > +static unsigned int cmdq_max_n_shift; > > > +module_param(cmdq_max_n_shift, uint, 0444); > > > +MODULE_PARM_DESC(cmdq_max_n_shift, > > > + "Cap on the command queue depth, as log2 of the number of entries. Zero means the hardware maximum; the queue never shrinks below one page."); > > > > The patch looks ok > > > > Reviewed-by: Jason Gunthorpe > > > > But I'd rather use lg2 as name, especially user visible, instead of > > n_shift. "shift" is a word for bitwise stuff, this is a 2**N log2 > > encoded value. > > This name has changed twice already. v5 took the value in entries. > Nicolin asked for a log2 value and named it after max_n_shift, which is > what the driver calls this quantity everywhere else. > > I would rather not rename it a third time without input from the > maintainer. > > Will, this is the user-visible name. Do you have a preference here? > Unless you want it changed I will leave v6 as it is. I don't have really strong opinions on naming, but since Jason has given a reasonably complete outline of the change and I have a small preference for the lg2-style naming (rather than exposing the name of an internal driver variable), it would be great if you can spin a v7 with that included so that I can pick it up. Thanks, Will