From patchwork Wed Dec 15 11:01:15 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tudor Ambarus X-Patchwork-Id: 12696262 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 2E68AC433FE for ; Wed, 15 Dec 2021 11:17:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=5CFm6gApsBg258XM9iPFZhgC1fKykJWOgkuTF4z7CFA=; b=C8rn5VuVbV/cY8 2Ayd3IQqEfjXoIXadXluSV3CWUZrPmPB8/j7jCBqMuOjbIQO27x6/k0Mw8B6KJM0GYxg19R/he2O+ RGLs+qwYtYl+JO/dPjtfz3EtU/QbdWzpMkQmuk9YQwCsSUfSrmo2n2q2lgW2dhCeo5rzYnN0c+iss PQPG3qUBM/XcggLdnbCsbY/mpxarEDoVKR5dSeK9mpLeS6o3BMAeqEH7bHxBg+gbMl+ggP2kCfLx/ NCfUzskh5DE7UAk2vK3V6tsYVRb33sao4fPtrqsNNLeidfv08vuu1J9IVrHtySJumjQJPVwr6DeUn lH0wNswb8vOsiXp8B1+g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mxSFc-000T53-10; Wed, 15 Dec 2021 11:15:13 +0000 Received: from esa.microchip.iphmx.com ([68.232.154.123]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mxS2h-000MFN-US for linux-arm-kernel@lists.infradead.org; Wed, 15 Dec 2021 11:01:53 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=microchip.com; i=@microchip.com; q=dns/txt; s=mchp; t=1639566111; x=1671102111; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=livyu8Olu9F9Ywh/gQcsyDAU8oKSPgD+q4+UxxEb734=; b=SNJpg7CWyCFPdmXLKn4GSCD4x6TbtRPMeTvmBCojq5H+2uZlhN9065gK KS/KvA7iVqiK9sgnwEN3YJfasRH2d1WlnjT9rSxXTWqCAT9rMeGDayLsY NMdtynY6kTElOdMXbtCWZZK/wj3E3iaryQG9Uhm0ZHaiKdOlQ92fDXA+F NePEhaygoJYqFaQaw9PMr1NzkxB8HxBZ40VLKsKkpn/c0ZZyEXFUtR+sp DtuNPE/sGwguzFi6JHMBA3DLrkjSEcuxso9/XOA0XWBQqJKJaJ0jdIGlC 6/MH6R8dicggTr3IiNZksaH8ahCnYqD83N2x4AcmbVexX3ZkAfFzepBRJ g==; IronPort-SDR: law3cO30f8LFLnfWd/Rjq4CEuz7T4Bx4DvtkSXmrdYQrIERp0Mxn4pOP7NmvXPxSkG3PqGKMiq XjPu05B9Y6dwIRL+6vs5GiM0jZyVdbievZ/vQAB11aOR69853E5NknJVUqnBvLAcbBHCDE2VMz uPYp7fUKVMzMhmnAr4LLCbtRNjib021fXDkN76B5tpwYIAwfbd6ks3Jf7uKPT4lOoHUxvxPl59 IUfBdty4gdUjhjdm6QnaVCKaEmK6j6B2zjF/xthNrkdTNwIOA6mID4d1lcqqgNk2Lg0kVaXFAR qR6Wc3cOyh1rwSOPitr0sGuh X-IronPort-AV: E=Sophos;i="5.88,207,1635231600"; d="scan'208";a="139842746" Received: from smtpout.microchip.com (HELO email.microchip.com) ([198.175.253.82]) by esa4.microchip.iphmx.com with ESMTP/TLS/AES256-SHA256; 15 Dec 2021 04:01:51 -0700 Received: from chn-vm-ex03.mchp-main.com (10.10.85.151) by chn-vm-ex04.mchp-main.com (10.10.85.152) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.17; Wed, 15 Dec 2021 04:01:51 -0700 Received: from ROB-ULT-M18064N.mchp-main.com (10.10.115.15) by chn-vm-ex03.mchp-main.com (10.10.85.151) with Microsoft SMTP Server id 15.1.2375.17 via Frontend Transport; Wed, 15 Dec 2021 04:01:48 -0700 From: Tudor Ambarus To: Subject: [PATCH v3 12/12] dmaengine: at_xdmac: Fix race over irq_status Date: Wed, 15 Dec 2021 13:01:15 +0200 Message-ID: <20211215110115.191749-13-tudor.ambarus@microchip.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20211215110115.191749-1-tudor.ambarus@microchip.com> References: <20211215110115.191749-1-tudor.ambarus@microchip.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211215_030152_140421_40A5EF29 X-CRM114-Status: GOOD ( 10.42 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Tudor Ambarus , mripard@kernel.org, linux-kernel@vger.kernel.org, ludovic.desroches@microchip.com, dmaengine@vger.kernel.org, linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.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. Move the dev_dbg that prints the irq_status in at_xdmac_handle_cyclic() and lower in at_xdmac_tasklet() where the IRQ is disabled. Signed-off-by: Tudor Ambarus --- drivers/dma/at_xdmac.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c index ba727751a9f6..a1da2b4b6d73 100644 --- a/drivers/dma/at_xdmac.c +++ b/drivers/dma/at_xdmac.c @@ -1611,6 +1611,8 @@ static void at_xdmac_handle_cyclic(struct at_xdmac_chan *atchan) struct dma_async_tx_descriptor *txd; spin_lock_irq(&atchan->lock); + dev_dbg(chan2dev(&atchan->chan), "%s: status=0x%08x\n", + __func__, atchan->irq_status); if (list_empty(&atchan->xfers_list)) { spin_unlock_irq(&atchan->lock); return; @@ -1623,6 +1625,7 @@ 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 +1644,6 @@ 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) @@ -1652,8 +1653,6 @@ 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), "%s: lld: mbr_sa=%pad, mbr_da=%pad, mbr_ubc=0x%08x\n", @@ -1670,15 +1669,17 @@ static void at_xdmac_tasklet(struct tasklet_struct *t) struct dma_async_tx_descriptor *txd; u32 error_mask; - dev_dbg(chan2dev(&atchan->chan), "%s: status=0x%08x\n", - __func__, atchan->irq_status); - 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; @@ -1686,7 +1687,6 @@ static void at_xdmac_tasklet(struct tasklet_struct *t) 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);