From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) (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 75CC529CA for ; Sun, 17 Oct 2021 07:07:26 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 55AEC60F23; Sun, 17 Oct 2021 07:07:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1634454446; bh=uYrWYaNw+y04uyy1r1WLDgEiohtXcV0xRVaH9SH36H8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=pd+b7WPWC6Eiej0nXxGyYVBEice/PLIcKYMLjtynosoywSbXMLRsWbl6HWNHiNwi2 NpLiqzPolVambyF+cY9V9DMKZKtDfwhS/s8ySxAOkou1wEQv8z/LbvqkZ/O5oYYVD7 255x+RRnHJIf84i4E9yRr6vOOoCN0tVbHaRbbQ+0= Date: Sun, 17 Oct 2021 09:07:18 +0200 From: Greg KH To: Manivannan Sadhasivam Cc: Manivannan Sadhasivam , hemantk@codeaurora.org, bbhatt@codeaurora.org, loic.poulain@linaro.org, wangqing@vivo.com, mhi@lists.linux.dev, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, Jakub Kicinski Subject: Re: [PATCH 2/3] bus: mhi: Add inbound buffers allocation flag Message-ID: References: <20211016065734.28802-1-manivannan.sadhasivam@linaro.org> <20211016065734.28802-3-manivannan.sadhasivam@linaro.org> <20211016163128.GC4048@thinkpad> Precedence: bulk X-Mailing-List: mhi@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211016163128.GC4048@thinkpad> On Sat, Oct 16, 2021 at 10:01:28PM +0530, Manivannan Sadhasivam wrote: > On Sat, Oct 16, 2021 at 09:39:53AM +0200, Greg KH wrote: > > On Sat, Oct 16, 2021 at 12:27:33PM +0530, Manivannan Sadhasivam wrote: > > > From: Loic Poulain > > > > > > Currently, the MHI controller driver defines which channels should > > > have their inbound buffers allocated and queued. But ideally, this is > > > something that should be decided by the MHI device driver instead, > > > which actually deals with that buffers. > > > > > > Add a flag parameter to mhi_prepare_for_transfer allowing to specify > > > if buffers have to be allocated and queued by the MHI stack. > > > > This is a horrible api. Now one has to go and look up why "0" was added > > to a function as a parameter. > > > > If you don't want to allocate the buffer, then make a function of that > > name and call that. As you only have one "flag", don't try to make > > something generic here that is obviously not generic at all. > > > > This is the only API that can be used by the client drivers to pass the > configurations to the MHI stack. So we wanted to have a flags parameter that > could be extended in the future also. Worry about future issues then, in the future :) > Regarding "0", the default behaviour is to not pre allocate the buffer at all. > So it made less sense to add a separate flag or an API for that. But again, this is now hard to understand and if you run across a '0' in the call, you have to go and look it up, breaking your reading flow. Please just create a new function for this new option, and then have both of them call the common function with a boolean for this "allocate or not" type of thing. We do this all the time in the kernel to make it easier to read and understand over time. thanks, greg k-h