Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751751AbbHTKbt (ORCPT ); Thu, 20 Aug 2015 06:31:49 -0400 Received: from denmail01-v4020.amcc.com ([192.195.68.30]:57962 "EHLO denmail01.amcc.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1751632AbbHTKbq (ORCPT ); Thu, 20 Aug 2015 06:31:46 -0400 From: Rameshwar Prasad Sahu To: vinod.koul@intel.com, dan.j.williams@intel.com Cc: dmaengine@vger.kernel.org, arnd@arndb.de, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, jcm@redhat.com, patches@apm.com, Rameshwar Prasad Sahu Subject: [PATCH] dmaengine: xgene-dma: Fix holding lock while calling tx callback in cleanup path Date: Thu, 20 Aug 2015 16:00:56 +0530 Message-Id: <1440066656-15516-1-git-send-email-rsahu@apm.com> X-Mailer: git-send-email 1.8.2.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3389 Lines: 106 This patch fixes the an locking issue where client callback performs further submission. Signed-off-by: Rameshwar Prasad Sahu --- drivers/dma/xgene-dma.c | 33 ++++++++++++++++++++++----------- 1 file changed, 22 insertions(+), 11 deletions(-) diff --git a/drivers/dma/xgene-dma.c b/drivers/dma/xgene-dma.c index d1c8809..0b82bc0 100644 --- a/drivers/dma/xgene-dma.c +++ b/drivers/dma/xgene-dma.c @@ -763,12 +763,17 @@ static void xgene_dma_cleanup_descriptors(struct xgene_dma_chan *chan) struct xgene_dma_ring *ring = &chan->rx_ring; struct xgene_dma_desc_sw *desc_sw, *_desc_sw; struct xgene_dma_desc_hw *desc_hw; + struct list_head ld_completed; u8 status; + INIT_LIST_HEAD(&ld_completed); + + spin_lock_bh(&chan->lock); + /* Clean already completed and acked descriptors */ xgene_dma_clean_completed_descriptor(chan); - /* Run the callback for each descriptor, in order */ + /* Move all completed descriptors to ld completed queue, in order */ list_for_each_entry_safe(desc_sw, _desc_sw, &chan->ld_running, node) { /* Get subsequent hw descriptor from DMA rx ring */ desc_hw = &ring->desc_hw[ring->head]; @@ -811,15 +816,17 @@ static void xgene_dma_cleanup_descriptors(struct xgene_dma_chan *chan) /* Mark this hw descriptor as processed */ desc_hw->m0 = cpu_to_le64(XGENE_DMA_DESC_EMPTY_SIGNATURE); - xgene_dma_run_tx_complete_actions(chan, desc_sw); - - xgene_dma_clean_running_descriptor(chan, desc_sw); - /* * Decrement the pending transaction count * as we have processed one */ chan->pending--; + + /* + * Delete this node from ld running queue and append it to + * ld completed queue for further processing + */ + list_move_tail(&desc_sw->node, &ld_completed); } /* @@ -828,6 +835,14 @@ static void xgene_dma_cleanup_descriptors(struct xgene_dma_chan *chan) * ahead and free the descriptors below. */ xgene_chan_xfer_ld_pending(chan); + + spin_unlock_bh(&chan->lock); + + /* Run the callback for each descriptor, in order */ + list_for_each_entry_safe(desc_sw, _desc_sw, &ld_completed, node) { + xgene_dma_run_tx_complete_actions(chan, desc_sw); + xgene_dma_clean_running_descriptor(chan, desc_sw); + } } static int xgene_dma_alloc_chan_resources(struct dma_chan *dchan) @@ -876,11 +891,11 @@ static void xgene_dma_free_chan_resources(struct dma_chan *dchan) if (!chan->desc_pool) return; - spin_lock_bh(&chan->lock); - /* Process all running descriptor */ xgene_dma_cleanup_descriptors(chan); + spin_lock_bh(&chan->lock); + /* Clean all link descriptor queues */ xgene_dma_free_desc_list(chan, &chan->ld_pending); xgene_dma_free_desc_list(chan, &chan->ld_running); @@ -1200,15 +1215,11 @@ static void xgene_dma_tasklet_cb(unsigned long data) { struct xgene_dma_chan *chan = (struct xgene_dma_chan *)data; - spin_lock_bh(&chan->lock); - /* Run all cleanup for descriptors which have been completed */ xgene_dma_cleanup_descriptors(chan); /* Re-enable DMA channel IRQ */ enable_irq(chan->rx_irq); - - spin_unlock_bh(&chan->lock); } static irqreturn_t xgene_dma_chan_ring_isr(int irq, void *id) -- 1.8.2.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/