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From: Vincent Whitchurch <vincent.whitchurch@axis.com>
To: sudeep.dutt@intel.com, ashutosh.dixit@intel.com,
	gregkh@linuxfoundation.org, arnd@arndb.de
Cc: linux-kernel@vger.kernel.org, Vincent Whitchurch <rabinv@axis.com>
Subject: [PATCH 5/8] vop: vringh: Do not crash if no DMA channel
Date: Wed, 16 Jan 2019 17:32:50 +0100	[thread overview]
Message-ID: <20190116163253.23780-6-vincent.whitchurch@axis.com> (raw)
In-Reply-To: <20190116163253.23780-1-vincent.whitchurch@axis.com>

Fallback gracefully if no DMA channel is provided instead of
dereferencing NULL pointers.

Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
---
 drivers/misc/mic/vop/vop_vringh.c | 32 +++++++++++++++++++------------
 1 file changed, 20 insertions(+), 12 deletions(-)

diff --git a/drivers/misc/mic/vop/vop_vringh.c b/drivers/misc/mic/vop/vop_vringh.c
index ccdfbb652123..18d6ecff1834 100644
--- a/drivers/misc/mic/vop/vop_vringh.c
+++ b/drivers/misc/mic/vop/vop_vringh.c
@@ -531,12 +531,12 @@ static int vop_virtio_copy_to_user(struct vop_vdev *vdev, void __user *ubuf,
 	void __iomem *dbuf = vpdev->hw_ops->ioremap(vpdev, daddr, len);
 	struct vop_vringh *vvr = &vdev->vvr[vr_idx];
 	struct vop_info *vi = dev_get_drvdata(&vpdev->dev);
-	size_t dma_alignment = 1 << vi->dma_ch->device->copy_align;
-	bool x200 = is_dma_copy_aligned(vi->dma_ch->device, 1, 1, 1);
+	size_t dma_alignment;
+	bool x200;
 	size_t dma_offset, partlen;
 	int err;
 
-	if (!VOP_USE_DMA) {
+	if (!VOP_USE_DMA || !vi->dma_ch) {
 		if (copy_to_user(ubuf, (void __force *)dbuf, len)) {
 			err = -EFAULT;
 			dev_err(vop_dev(vdev), "%s %d err %d\n",
@@ -548,6 +548,9 @@ static int vop_virtio_copy_to_user(struct vop_vdev *vdev, void __user *ubuf,
 		goto err;
 	}
 
+	dma_alignment = 1 << vi->dma_ch->device->copy_align;
+	x200 = is_dma_copy_aligned(vi->dma_ch->device, 1, 1, 1);
+
 	dma_offset = daddr - round_down(daddr, dma_alignment);
 	daddr -= dma_offset;
 	len += dma_offset;
@@ -606,18 +609,23 @@ static int vop_virtio_copy_from_user(struct vop_vdev *vdev, void __user *ubuf,
 	void __iomem *dbuf = vpdev->hw_ops->ioremap(vpdev, daddr, len);
 	struct vop_vringh *vvr = &vdev->vvr[vr_idx];
 	struct vop_info *vi = dev_get_drvdata(&vdev->vpdev->dev);
-	size_t dma_alignment = 1 << vi->dma_ch->device->copy_align;
-	bool x200 = is_dma_copy_aligned(vi->dma_ch->device, 1, 1, 1);
+	size_t dma_alignment;
+	bool x200;
 	size_t partlen;
-	bool dma = VOP_USE_DMA;
+	bool dma = VOP_USE_DMA && vi->dma_ch;
 	int err = 0;
 
-	if (daddr & (dma_alignment - 1)) {
-		vdev->tx_dst_unaligned += len;
-		dma = false;
-	} else if (ALIGN(len, dma_alignment) > dlen) {
-		vdev->tx_len_unaligned += len;
-		dma = false;
+	if (dma) {
+		dma_alignment = 1 << vi->dma_ch->device->copy_align;
+		x200 = is_dma_copy_aligned(vi->dma_ch->device, 1, 1, 1);
+
+		if (daddr & (dma_alignment - 1)) {
+			vdev->tx_dst_unaligned += len;
+			dma = false;
+		} else if (ALIGN(len, dma_alignment) > dlen) {
+			vdev->tx_len_unaligned += len;
+			dma = false;
+		}
 	}
 
 	if (!dma)
-- 
2.20.0


  parent reply	other threads:[~2019-01-16 16:33 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-01-16 16:32 [PATCH 0/8] Virtio-over-PCIe on non-MIC Vincent Whitchurch
2019-01-16 16:32 ` [PATCH 1/8] vop: Use %z for size_t Vincent Whitchurch
2019-01-16 16:32 ` [PATCH 2/8] vop: Cast pointers to uintptr_t Vincent Whitchurch
2019-01-16 17:39   ` Joe Perches
2019-01-22 10:41   ` Greg KH
2019-01-16 16:32 ` [PATCH 3/8] vop: Add definition of readq/writeq if missing Vincent Whitchurch
2019-01-16 16:32 ` [PATCH 4/8] vop: Allow building on more systems Vincent Whitchurch
2019-01-16 16:32 ` Vincent Whitchurch [this message]
2019-01-16 16:32 ` [PATCH 6/8] vop: Fix handling of >32 feature bits Vincent Whitchurch
2019-01-16 16:32 ` [PATCH 7/8] vop: Use consistent DMA Vincent Whitchurch
2019-01-16 16:32 ` [PATCH 8/8] vop: Add loopback Vincent Whitchurch
2019-01-16 17:07 ` [PATCH 0/8] Virtio-over-PCIe on non-MIC Arnd Bergmann
2019-01-17 10:54   ` Vincent Whitchurch
2019-01-17 12:39     ` Arnd Bergmann
2019-01-17 15:15       ` Christoph Hellwig
2019-01-17 15:19         ` Christoph Hellwig
2019-01-17 15:31           ` Arnd Bergmann
2019-01-17 15:19       ` Vincent Whitchurch
2019-01-17 15:21         ` Christoph Hellwig
2019-01-17 15:32           ` Vincent Whitchurch
2019-01-17 15:46             ` Christoph Hellwig
2019-01-17 16:18               ` Arnd Bergmann
2019-01-17 15:53         ` Arnd Bergmann
2019-01-17 16:26           ` Vincent Whitchurch
2019-01-17 16:34             ` Arnd Bergmann
2019-01-17 22:17         ` Logan Gunthorpe
2019-01-18 23:49 ` Stephen Warren
2019-01-21 16:25   ` Vincent Whitchurch
2019-01-22 10:45 ` Greg KH

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