From: Elena Reshetova <elena.reshetova@intel.com>
To: davem@davemloft.net
Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-mediatek@lists.infradead.org, linux-rdma@vger.kernel.org,
linux-hams@vger.kernel.org, linux-ppp@vger.kernel.org,
ganeshgr@chelsio.com, nbd@openwrt.org, john@phrozen.org,
sean.wang@mediatek.com, matthias.bgg@gmail.com,
yishaih@mellanox.com, saeedm@mellanox.com, matanb@mellanox.com,
tariqt@mellanox.com, leonro@mellanox.com,
ajk@comnets.uni-bremen.de, paulus@samba.org, zbr@ioremap.net,
peterz@infradead.org, keescook@chromium.org,
Elena Reshetova <elena.reshetova@intel.com>
Subject: [PATCH 02/15] drivers, net, ethernet: convert mtk_eth.dma_refcnt from atomic_t to refcount_t
Date: Fri, 20 Oct 2017 07:23:36 +0000 [thread overview]
Message-ID: <1508484229-19706-3-git-send-email-elena.reshetova@intel.com> (raw)
In-Reply-To: <1508484229-19706-1-git-send-email-elena.reshetova@intel.com>
atomic_t variables are currently used to implement reference
counters with the following properties:
- counter is initialized to 1 using atomic_set()
- a resource is freed upon counter reaching zero
- once counter reaches zero, its further
increments aren't allowed
- counter schema uses basic atomic operations
(set, inc, inc_not_zero, dec_and_test, etc.)
Such atomic variables should be converted to a newly provided
refcount_t type and API that prevents accidental counter overflows
and underflows. This is important since overflows and underflows
can lead to use-after-free situation and be exploitable.
The variable mtk_eth.dma_refcnt is used as pure reference counter.
Convert it to refcount_t and fix up the operations.
Suggested-by: Kees Cook <keescook@chromium.org>
Reviewed-by: David Windsor <dwindsor@gmail.com>
Reviewed-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
---
drivers/net/ethernet/mediatek/mtk_eth_soc.c | 8 +++++---
drivers/net/ethernet/mediatek/mtk_eth_soc.h | 4 +++-
2 files changed, 8 insertions(+), 4 deletions(-)
diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
index 5e81a72..54adfd9 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
@@ -1817,7 +1817,7 @@ static int mtk_open(struct net_device *dev)
struct mtk_eth *eth = mac->hw;
/* we run 2 netdevs on the same dma ring so we only bring it up once */
- if (!atomic_read(ð->dma_refcnt)) {
+ if (!refcount_read(ð->dma_refcnt)) {
int err = mtk_start_dma(eth);
if (err)
@@ -1827,8 +1827,10 @@ static int mtk_open(struct net_device *dev)
napi_enable(ð->rx_napi);
mtk_tx_irq_enable(eth, MTK_TX_DONE_INT);
mtk_rx_irq_enable(eth, MTK_RX_DONE_INT);
+ refcount_set(ð->dma_refcnt, 1);
}
- atomic_inc(ð->dma_refcnt);
+ else
+ refcount_inc(ð->dma_refcnt);
phy_start(dev->phydev);
netif_start_queue(dev);
@@ -1868,7 +1870,7 @@ static int mtk_stop(struct net_device *dev)
phy_stop(dev->phydev);
/* only shutdown DMA if this is the last user */
- if (!atomic_dec_and_test(ð->dma_refcnt))
+ if (!refcount_dec_and_test(ð->dma_refcnt))
return 0;
mtk_tx_irq_disable(eth, MTK_TX_DONE_INT);
diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.h b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
index 3d3c24a..a3af466 100644
--- a/drivers/net/ethernet/mediatek/mtk_eth_soc.h
+++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.h
@@ -15,6 +15,8 @@
#ifndef MTK_ETH_H
#define MTK_ETH_H
+#include <linux/refcount.h>
+
#define MTK_QDMA_PAGE_SIZE 2048
#define MTK_MAX_RX_LENGTH 1536
#define MTK_TX_DMA_BUF_LEN 0x3fff
@@ -632,7 +634,7 @@ struct mtk_eth {
struct regmap *pctl;
u32 chip_id;
bool hwlro;
- atomic_t dma_refcnt;
+ refcount_t dma_refcnt;
struct mtk_tx_ring tx_ring;
struct mtk_rx_ring rx_ring[MTK_MAX_RX_RING_NUM];
struct mtk_rx_ring rx_ring_qdma;
--
2.7.4
next prev parent reply other threads:[~2017-10-20 7:23 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-20 7:23 [PATCH 00/15] networking drivers refcount_t conversions Elena Reshetova
2017-10-20 7:23 ` [PATCH 01/15] drivers, net, ethernet: convert clip_entry.refcnt from atomic_t to refcount_t Elena Reshetova
2017-10-20 7:23 ` Elena Reshetova [this message]
[not found] ` <1508484229-19706-3-git-send-email-elena.reshetova-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
2017-10-20 8:08 ` [PATCH 02/15] drivers, net, ethernet: convert mtk_eth.dma_refcnt " Sean Wang
2017-10-20 10:37 ` Reshetova, Elena
2017-10-22 4:06 ` Sean Wang
2017-10-23 6:37 ` Reshetova, Elena
2017-10-20 7:23 ` [PATCH 03/15] drivers, net, mlx4: convert mlx4_cq.refcount " Elena Reshetova
[not found] ` <1508484229-19706-1-git-send-email-elena.reshetova-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
2017-10-20 7:23 ` [PATCH 04/15] drivers, net, mlx4: convert mlx4_qp.refcount " Elena Reshetova
2017-10-20 7:23 ` [PATCH 05/15] drivers, net, mlx4: convert mlx4_srq.refcount " Elena Reshetova
2017-10-20 7:23 ` [PATCH 06/15] drivers, net, mlx5: convert mlx5_cq.refcount " Elena Reshetova
2017-10-20 7:23 ` [PATCH 07/15] drivers, net, mlx5: convert fs_node.refcount " Elena Reshetova
2017-10-20 7:23 ` [PATCH 08/15] drivers, net, hamradio: convert sixpack.refcnt " Elena Reshetova
2017-10-20 7:23 ` [PATCH 09/15] drivers, net: convert masces_rx_sa.refcnt " Elena Reshetova
2017-10-20 7:23 ` [PATCH 10/15] drivers, net: convert masces_rx_sc.refcnt " Elena Reshetova
2017-10-20 7:23 ` [PATCH 11/15] drivers, net: convert masces_tx_sa.refcnt " Elena Reshetova
2017-10-20 7:23 ` [PATCH 12/15] drivers, net, ppp: convert asyncppp.refcnt " Elena Reshetova
2017-10-20 7:23 ` [PATCH 13/15] drivers, net, ppp: convert ppp_file.refcnt " Elena Reshetova
2017-10-20 7:23 ` [PATCH 14/15] drivers, net, ppp: convert syncppp.refcnt " Elena Reshetova
2017-10-20 7:23 ` [PATCH 15/15] drivers, connector: convert cn_callback_entry.refcnt " Elena Reshetova
2017-10-22 1:31 ` [PATCH 00/15] networking drivers refcount_t conversions David Miller
2017-10-23 6:34 ` Reshetova, Elena
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