From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Burton Date: Thu, 02 May 2019 00:08:01 +0000 Subject: Re: [PATCH 4/7] dma-direct: provide generic support for uncached kernel segments Message-Id: <20190502000759.4ii2wuogc6fuc3jh@pburton-laptop> List-Id: References: <20190430110032.25301-1-hch@lst.de> <20190430110032.25301-5-hch@lst.de> <20190501171857.chfxqntvm6r4xrr4@pburton-laptop> <20190501172912.GA19375@lst.de> <20190501174033.6rj5aiopdeo4uqpw@pburton-laptop> <20190501174905.GA20458@lst.de> In-Reply-To: <20190501174905.GA20458@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Christoph Hellwig Cc: Ralf Baechle , James Hogan , Ley Foon Tan , Michal Simek , Bartlomiej Zolnierkiewicz , "linux-mips@vger.kernel.org" , "iommu@lists.linux-foundation.org" , "linux-kernel@vger.kernel.org" , "linux-fbdev@vger.kernel.org" Hi Christoph, On Wed, May 01, 2019 at 07:49:05PM +0200, Christoph Hellwig wrote: > On Wed, May 01, 2019 at 05:40:34PM +0000, Paul Burton wrote: > > > > If it is necessary then as-is this code will clear the allocated memory > > > > using uncached writes which will be pretty slow. It would be much more > > > > efficient to perform the memset before arch_dma_prep_coherent() & before > > > > converting ret to an uncached address. > > > > > > Yes, we could do that. > > > > Great; using cached writes would match the existing MIPS behavior. > > Can you test the stack with the two updated patches and ack them if > they are fine? That would allow getting at least the infrastructure > and mips in for this merge window. Did you send a v2 of this patch? If so it hasn't showed up in my inbox, nor on the linux-mips archive on lore.kernel.org. Thanks, Paul