From patchwork Tue Nov 16 11:20:36 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tudor Ambarus X-Patchwork-Id: 517623 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B97E0C4332F for ; Tue, 16 Nov 2021 11:22:22 +0000 (UTC) Received: from vger.kernel.org (unknown [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8BD2961994 for ; Tue, 16 Nov 2021 11:22:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 8BD2961994 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=microchip.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234972AbhKPLZC (ORCPT ); Tue, 16 Nov 2021 06:25:02 -0500 Received: from esa.microchip.iphmx.com ([68.232.153.233]:8935 "EHLO esa.microchip.iphmx.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234894AbhKPLYa (ORCPT ); Tue, 16 Nov 2021 06:24:30 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=microchip.com; i=@microchip.com; q=dns/txt; s=mchp; t=1637061693; x=1668597693; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=wxTxrAyDEObrB+6U2ISe3JfymaOVc1XxubqpmlFsG4s=; b=kXYLc/l1Jw8i4Mc574yLMUEFhVX1EQ0lCcS81UBiOIiC7lOpBPaj9MwW 1ix/SZJ64CfIpM/uCY24MobeWlyiONcvGEumC/3pf64AfOPSXyT2SeIIf rWiiLEUDRY8LhPhstuueJ4bNfDBy4YmLA4NvYkxVM5T6LfosaHqqp+Oxz /HVxiR/YIsra051Q6AF8l4sRptnqU/XQcM25uOw2ngSOtHezCoo4xZFVF jps+liwgDN9QxWNaSRzRy5Un3pb8OUrtNFUA28Qdq71I3HcCbqUR71nl4 G1QCVrDqwVVFJYo43Wbil2QIm7luVQKR2VVB4H76h+qz7ZInBjrGysM2h w==; IronPort-SDR: +klTsaNsJRHc5UsqIf+tQaaWFIm16NfFRFpzoUyBGO6O8OEvukF0O4L96+arZyMRX/SkdOQZJq LmzV75PpBvQTEWYooZM4m0WhyAVvSX7ZNWmXmr+q4suV3MU1bCUE6nyt6yf64mgqT0KMHKxWwN KKjQb/yrF8f9Zv+CJYrNPTvJX5DqlNaWCPgQV5qsRpQqGKRkcQyztyE8Gf7w75iPNXivAbFyWl eE2xhg6sJAugeXUTCobhUPlR6mdTOoIXy788ooEG3NMAsQ7g25Bd7rCKCm61nnh08OHzlOBHzq ASmeDMtMKdzp1PHkvTd4Ep7J X-IronPort-AV: E=Sophos;i="5.87,239,1631602800"; d="scan'208";a="144082954" Received: from smtpout.microchip.com (HELO email.microchip.com) ([198.175.253.82]) by esa3.microchip.iphmx.com with ESMTP/TLS/AES256-SHA256; 16 Nov 2021 04:21:31 -0700 Received: from chn-vm-ex04.mchp-main.com (10.10.85.152) by chn-vm-ex03.mchp-main.com (10.10.85.151) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.14; Tue, 16 Nov 2021 04:21:29 -0700 Received: from ROB-ULT-M18064N.mchp-main.com (10.10.115.15) by chn-vm-ex04.mchp-main.com (10.10.85.152) with Microsoft SMTP Server id 15.1.2176.14 via Frontend Transport; Tue, 16 Nov 2021 04:21:25 -0700 From: Tudor Ambarus To: , , , , CC: , , , , , , , Tudor Ambarus Subject: [PATCH 13/13] dmaengine: at_xdmac: Fix race over irq_status Date: Tue, 16 Nov 2021 13:20:36 +0200 Message-ID: <20211116112036.96349-14-tudor.ambarus@microchip.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20211116112036.96349-1-tudor.ambarus@microchip.com> References: <20211116112036.96349-1-tudor.ambarus@microchip.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org Tasklets run with interrupts enabled, so we need to protect atchan->irq_status with spin_lock_irq() otherwise the tasklet can be interrupted by the IRQ that modifies irq_status. While at this, rewrite at_xdmac_tasklet() so that we get rid of a level of indentation. Fixes: e1f7c9eee707 ("dmaengine: at_xdmac: creation of the atmel eXtended DMA Controller driver") Signed-off-by: Tudor Ambarus --- drivers/dma/at_xdmac.c | 80 +++++++++++++++++++----------------------- 1 file changed, 37 insertions(+), 43 deletions(-) diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c index ccd6ddb12b83..082c18d45188 100644 --- a/drivers/dma/at_xdmac.c +++ b/drivers/dma/at_xdmac.c @@ -1623,6 +1623,7 @@ static void at_xdmac_handle_cyclic(struct at_xdmac_chan *atchan) dmaengine_desc_get_callback_invoke(txd, NULL); } +/* Called with atchan->lock held. */ static void at_xdmac_handle_error(struct at_xdmac_chan *atchan) { struct at_xdmac *atxdmac = to_at_xdmac(atchan->chan.device); @@ -1641,8 +1642,6 @@ static void at_xdmac_handle_error(struct at_xdmac_chan *atchan) if (atchan->irq_status & AT_XDMAC_CIS_ROIS) dev_err(chan2dev(&atchan->chan), "request overflow error!!!"); - spin_lock_irq(&atchan->lock); - /* Channel must be disabled first as it's not done automatically */ at_xdmac_write(atxdmac, AT_XDMAC_GD, atchan->mask); while (at_xdmac_read(atxdmac, AT_XDMAC_GS) & atchan->mask) @@ -1652,10 +1651,8 @@ static void at_xdmac_handle_error(struct at_xdmac_chan *atchan) struct at_xdmac_desc, xfer_node); - spin_unlock_irq(&atchan->lock); - /* Print bad descriptor's details if needed */ - dev_dbg(chan2dev(&atchan->chan), + dev_err(chan2dev(&atchan->chan), "%s: lld: mbr_sa=%pad, mbr_da=%pad, mbr_ubc=0x%08x\n", __func__, &bad_desc->lld.mbr_sa, &bad_desc->lld.mbr_da, bad_desc->lld.mbr_ubc); @@ -1665,55 +1662,52 @@ static void at_xdmac_handle_error(struct at_xdmac_chan *atchan) static void at_xdmac_tasklet(struct tasklet_struct *t) { + struct dma_async_tx_descriptor *txd; struct at_xdmac_chan *atchan = from_tasklet(atchan, t, tasklet); struct at_xdmac_desc *desc; u32 error_mask; + if (at_xdmac_chan_is_cyclic(atchan)) + return at_xdmac_handle_cyclic(atchan); + + error_mask = AT_XDMAC_CIS_RBEIS | AT_XDMAC_CIS_WBEIS | + AT_XDMAC_CIS_ROIS; + + spin_lock_irq(&atchan->lock); dev_dbg(chan2dev(&atchan->chan), "%s: status=0x%08x\n", __func__, atchan->irq_status); + if (!(atchan->irq_status & AT_XDMAC_CIS_LIS) && + !(atchan->irq_status & error_mask)) { + return spin_unlock_irq(&atchan->lock); + } - error_mask = AT_XDMAC_CIS_RBEIS - | AT_XDMAC_CIS_WBEIS - | AT_XDMAC_CIS_ROIS; - - if (at_xdmac_chan_is_cyclic(atchan)) { - at_xdmac_handle_cyclic(atchan); - } else if ((atchan->irq_status & AT_XDMAC_CIS_LIS) - || (atchan->irq_status & error_mask)) { - struct dma_async_tx_descriptor *txd; - - if (atchan->irq_status & error_mask) - at_xdmac_handle_error(atchan); - - spin_lock_irq(&atchan->lock); - desc = list_first_entry(&atchan->xfers_list, - struct at_xdmac_desc, - xfer_node); - dev_vdbg(chan2dev(&atchan->chan), "%s: desc 0x%p\n", __func__, desc); - if (!desc->active_xfer) { - dev_err(chan2dev(&atchan->chan), "Xfer not active: exiting"); - spin_unlock_irq(&atchan->lock); - return; - } + if (atchan->irq_status & error_mask) + at_xdmac_handle_error(atchan); - txd = &desc->tx_dma_desc; - dma_cookie_complete(txd); - /* Remove the transfer from the transfer list. */ - list_del(&desc->xfer_node); - spin_unlock_irq(&atchan->lock); + desc = list_first_entry(&atchan->xfers_list, struct at_xdmac_desc, + xfer_node); + dev_vdbg(chan2dev(&atchan->chan), "%s: desc 0x%p\n", __func__, desc); + if (!desc->active_xfer) { + dev_err(chan2dev(&atchan->chan), "Xfer not active: exiting"); + return spin_unlock_irq(&atchan->lock); + } - if (txd->flags & DMA_PREP_INTERRUPT) - dmaengine_desc_get_callback_invoke(txd, NULL); + txd = &desc->tx_dma_desc; + dma_cookie_complete(txd); + /* Remove the transfer from the transfer list. */ + list_del(&desc->xfer_node); + spin_unlock_irq(&atchan->lock); - dma_run_dependencies(txd); + if (txd->flags & DMA_PREP_INTERRUPT) + dmaengine_desc_get_callback_invoke(txd, NULL); - spin_lock_irq(&atchan->lock); - /* Move the xfer descriptors into the free descriptors list. */ - list_splice_tail_init(&desc->descs_list, - &atchan->free_descs_list); - at_xdmac_advance_work(atchan); - spin_unlock_irq(&atchan->lock); - } + dma_run_dependencies(txd); + + spin_lock_irq(&atchan->lock); + /* Move the xfer descriptors into the free descriptors list. */ + list_splice_tail_init(&desc->descs_list, &atchan->free_descs_list); + at_xdmac_advance_work(atchan); + spin_unlock_irq(&atchan->lock); } static irqreturn_t at_xdmac_interrupt(int irq, void *dev_id)