From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:41674 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754019AbdCTKJ7 (ORCPT ); Mon, 20 Mar 2017 06:09:59 -0400 Subject: Patch "dmaengine: iota: ioat_alloc_chan_resources should not perform sleeping allocations." has been added to the 4.9-stable tree To: kjlx@templeofstupid.com, dave.jiang@intel.com, gregkh@linuxfoundation.org, vinod.koul@intel.com Cc: , From: Date: Mon, 20 Mar 2017 11:09:45 +0100 Message-ID: <1490004585245105@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled dmaengine: iota: ioat_alloc_chan_resources should not perform sleeping allocations. to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: dmaengine-iota-ioat_alloc_chan_resources-should-not-perform-sleeping-allocations.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 21d25f6a4217e755906cb548b55ddab39d0e88b9 Mon Sep 17 00:00:00 2001 From: Krister Johansen Date: Wed, 4 Jan 2017 01:22:52 -0800 Subject: dmaengine: iota: ioat_alloc_chan_resources should not perform sleeping allocations. From: Krister Johansen commit 21d25f6a4217e755906cb548b55ddab39d0e88b9 upstream. On a kernel with DEBUG_LOCKS, ioat_free_chan_resources triggers an in_interrupt() warning. With PROVE_LOCKING, it reports detecting a SOFTIRQ-safe to SOFTIRQ-unsafe lock ordering in the same code path. This is because dma_generic_alloc_coherent() checks if the GFP flags permit blocking. It allocates from different subsystems if blocking is permitted. The free path knows how to return the memory to the correct allocator. If GFP_KERNEL is specified then the alloc and free end up going through cma_alloc(), which uses mutexes. Given that ioat_free_chan_resources() can be called in interrupt context, ioat_alloc_chan_resources() must specify GFP_NOWAIT so that the allocations do not block and instead use an allocator that uses spinlocks. Signed-off-by: Krister Johansen Acked-by: Dave Jiang Signed-off-by: Vinod Koul Signed-off-by: Greg Kroah-Hartman --- drivers/dma/ioat/init.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/drivers/dma/ioat/init.c +++ b/drivers/dma/ioat/init.c @@ -691,7 +691,7 @@ static int ioat_alloc_chan_resources(str /* doing 2 32bit writes to mmio since 1 64b write doesn't work */ ioat_chan->completion = dma_pool_zalloc(ioat_chan->ioat_dma->completion_pool, - GFP_KERNEL, &ioat_chan->completion_dma); + GFP_NOWAIT, &ioat_chan->completion_dma); if (!ioat_chan->completion) return -ENOMEM; @@ -701,7 +701,7 @@ static int ioat_alloc_chan_resources(str ioat_chan->reg_base + IOAT_CHANCMP_OFFSET_HIGH); order = IOAT_MAX_ORDER; - ring = ioat_alloc_ring(c, order, GFP_KERNEL); + ring = ioat_alloc_ring(c, order, GFP_NOWAIT); if (!ring) return -ENOMEM; Patches currently in stable-queue which might be from kjlx@templeofstupid.com are queue-4.9/dmaengine-iota-ioat_alloc_chan_resources-should-not-perform-sleeping-allocations.patch