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| author | Elena Reshetova <elena.reshetova@intel.com> | 2017-10-20 10:23:36 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-10-22 02:22:38 +0100 |
| commit | c6d4e63e065e796d2f2734c1e4e13f85f1c1c5e4 (patch) | |
| tree | 378dcc65e175a716d39e1ca417fcc2906b862233 /drivers/net/ethernet/mediatek | |
| parent | eaf6ab76430881c30695a9195ce37d6b11b04997 (diff) | |
| download | linux-c6d4e63e065e796d2f2734c1e4e13f85f1c1c5e4.tar.bz2 | |
drivers, net, ethernet: convert mtk_eth.dma_refcnt from atomic_t to refcount_t
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>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/ethernet/mediatek')
| -rw-r--r-- | drivers/net/ethernet/mediatek/mtk_eth_soc.c | 8 | ||||
| -rw-r--r-- | 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 5e81a7263654..54adfd967858 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 3d3c24a28112..a3af4660de81 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; |