From mboxrd@z Thu Jan 1 00:00:00 1970 From: boris.brezillon@free-electrons.com (Boris Brezillon) Date: Wed, 30 Mar 2016 20:18:31 +0200 Subject: [PATCH v2 4/7] scatterlist: add sg_alloc_table_from_buf() helper In-Reply-To: <20160330165143.GI2350@sirena.org.uk> References: <1459352394-22810-1-git-send-email-boris.brezillon@free-electrons.com> <1459352394-22810-5-git-send-email-boris.brezillon@free-electrons.com> <20160330165143.GI2350@sirena.org.uk> Message-ID: <20160330201831.38e1d6bd@bbrezillon> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wed, 30 Mar 2016 09:51:43 -0700 Mark Brown wrote: > On Wed, Mar 30, 2016 at 05:39:51PM +0200, Boris Brezillon wrote: > > sg_alloc_table_from_buf() provides an easy solution to create an sg_table > > from a virtual address pointer. This function takes care of dealing with > > vmallocated buffers, buffer alignment, or DMA engine limitations (maximum > > DMA transfer size). > > This seems nice. Should we also have a further helper on top of this > which will get constraints from a dmaengine, it seems like it'd be a > common need? Yep, we could create a wrapper extracting dma_slave caps info, converting it to sg_constraints and calling sg_alloc_table_from_buf(). But let's try to get this function accepted first, and I'll send another patch providing this wrapper. BTW, do you see other things that should be added in sg_constraints? -- Boris Brezillon, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com