From patchwork Thu Jul 23 01:59:31 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kamal Mostafa X-Patchwork-Id: 499184 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id B7D391402A0; Thu, 23 Jul 2015 12:16:49 +1000 (AEST) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1ZI63x-0008Tp-GF; Thu, 23 Jul 2015 02:16:45 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1ZI5pO-00009h-Di for kernel-team@lists.ubuntu.com; Thu, 23 Jul 2015 02:01:42 +0000 Received: from 1.general.kamal.us.vpn ([10.172.68.52] helo=fourier) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.76) (envelope-from ) id 1ZI5pO-0005fH-1o; Thu, 23 Jul 2015 02:01:42 +0000 Received: from kamal by fourier with local (Exim 4.82) (envelope-from ) id 1ZI5pL-0006AE-PY; Wed, 22 Jul 2015 19:01:39 -0700 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Subject: [PATCH 3.13.y-ckt 053/132] dmaengine: mv_xor: bug fix for racing condition in descriptors cleanup Date: Wed, 22 Jul 2015 18:59:31 -0700 Message-Id: <1437616850-23266-54-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1437616850-23266-1-git-send-email-kamal@canonical.com> References: <1437616850-23266-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.13 Cc: Lior Amsalem , Vinod Koul , Maxime Ripard , Kamal Mostafa X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com 3.13.11-ckt24 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Lior Amsalem commit 9136291f1dbc1d4d1cacd2840fb35f4f3ce16c46 upstream. This patch fixes a bug in the XOR driver where the cleanup function can be called and free descriptors that never been processed by the engine (which result in data errors). The cleanup function will free descriptors based on the ownership bit in the descriptors. Fixes: ff7b04796d98 ("dmaengine: DMA engine driver for Marvell XOR engine") Signed-off-by: Lior Amsalem Signed-off-by: Maxime Ripard Reviewed-by: Ofer Heifetz Signed-off-by: Vinod Koul Signed-off-by: Kamal Mostafa --- drivers/dma/mv_xor.c | 72 +++++++++++++++++++++++++++++++++------------------- drivers/dma/mv_xor.h | 1 + 2 files changed, 47 insertions(+), 26 deletions(-) diff --git a/drivers/dma/mv_xor.c b/drivers/dma/mv_xor.c index 29c8a06..b01f711 100644 --- a/drivers/dma/mv_xor.c +++ b/drivers/dma/mv_xor.c @@ -316,7 +316,8 @@ static void __mv_xor_slot_cleanup(struct mv_xor_chan *mv_chan) dma_cookie_t cookie = 0; int busy = mv_chan_is_busy(mv_chan); u32 current_desc = mv_chan_get_current_desc(mv_chan); - int seen_current = 0; + int current_cleaned = 0; + struct mv_xor_desc *hw_desc; dev_dbg(mv_chan_to_devp(mv_chan), "%s %d\n", __func__, __LINE__); dev_dbg(mv_chan_to_devp(mv_chan), "current_desc %x\n", current_desc); @@ -328,38 +329,57 @@ static void __mv_xor_slot_cleanup(struct mv_xor_chan *mv_chan) list_for_each_entry_safe(iter, _iter, &mv_chan->chain, chain_node) { - prefetch(_iter); - prefetch(&_iter->async_tx); - /* do not advance past the current descriptor loaded into the - * hardware channel, subsequent descriptors are either in - * process or have not been submitted - */ - if (seen_current) - break; + /* clean finished descriptors */ + hw_desc = iter->hw_desc; + if (hw_desc->status & XOR_DESC_SUCCESS) { + cookie = mv_xor_run_tx_complete_actions(iter, mv_chan, + cookie); - /* stop the search if we reach the current descriptor and the - * channel is busy - */ - if (iter->async_tx.phys == current_desc) { - seen_current = 1; - if (busy) + /* done processing desc, clean slot */ + mv_xor_clean_slot(iter, mv_chan); + + /* break if we did cleaned the current */ + if (iter->async_tx.phys == current_desc) { + current_cleaned = 1; + break; + } + } else { + if (iter->async_tx.phys == current_desc) { + current_cleaned = 0; break; + } } - - cookie = mv_xor_run_tx_complete_actions(iter, mv_chan, cookie); - - if (mv_xor_clean_slot(iter, mv_chan)) - break; } if ((busy == 0) && !list_empty(&mv_chan->chain)) { - struct mv_xor_desc_slot *chain_head; - chain_head = list_entry(mv_chan->chain.next, - struct mv_xor_desc_slot, - chain_node); - - mv_xor_start_new_chain(mv_chan, chain_head); + if (current_cleaned) { + /* + * current descriptor cleaned and removed, run + * from list head + */ + iter = list_entry(mv_chan->chain.next, + struct mv_xor_desc_slot, + chain_node); + mv_xor_start_new_chain(mv_chan, iter); + } else { + if (!list_is_last(&iter->chain_node, &mv_chan->chain)) { + /* + * descriptors are still waiting after + * current, trigger them + */ + iter = list_entry(iter->chain_node.next, + struct mv_xor_desc_slot, + chain_node); + mv_xor_start_new_chain(mv_chan, iter); + } else { + /* + * some descriptors are still waiting + * to be cleaned + */ + tasklet_schedule(&mv_chan->irq_tasklet); + } + } } if (cookie > 0) diff --git a/drivers/dma/mv_xor.h b/drivers/dma/mv_xor.h index d074922..5d14e4b 100644 --- a/drivers/dma/mv_xor.h +++ b/drivers/dma/mv_xor.h @@ -33,6 +33,7 @@ #define XOR_OPERATION_MODE_XOR 0 #define XOR_OPERATION_MODE_MEMCPY 2 #define XOR_DESCRIPTOR_SWAP BIT(14) +#define XOR_DESC_SUCCESS 0x40000000 #define XOR_CURR_DESC(chan) (chan->mmr_high_base + 0x10 + (chan->idx * 4)) #define XOR_NEXT_DESC(chan) (chan->mmr_high_base + 0x00 + (chan->idx * 4))