net: stmmac: Fix potential integer overflow

[ Upstream commit 52e597d3e2e6e5bfce47559eb22b955ac17b3826 ]

The commit d96febedfde2 ("net: stmmac: arrange Tx tail pointer update
to stmmac_flush_tx_descriptors") introduced the following coverity
warning:-

  1. Unintentional integer overflow (OVERFLOW_BEFORE_WIDEN)
     overflow_before_widen: Potentially overflowing expression
     'tx_q->cur_tx * desc_size' with type 'unsigned int' (32 bits,
     unsigned) is evaluated using 32-bit arithmetic, and then used in a
     context that expects an expression of type dma_addr_t (64 bits,
     unsigned).

Fixed this by assigning tx_tail_addr to dma_addr_t type, as dma_addr_t
datatype is decided by CONFIG_ARCH_DMA_ADDR_T_64_BIT.

Fixes: d96febedfde2 ("net: stmmac: arrange Tx tail pointer update to stmmac_flush_tx_descriptors")
Signed-off-by: Wong Vee Khee <vee.khee.wong@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac.h b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
index b6cd43eda7acc14bf2b8ed3588998511f3cbbf1d..8aa55612d0949c0c5abe78218126e963b23fcd4f 100644 (file)
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac.h
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
@@ -75,7 +75,7 @@ struct stmmac_tx_queue {
        unsigned int cur_tx;
        unsigned int dirty_tx;
        dma_addr_t dma_tx_phy;
-       u32 tx_tail_addr;
+       dma_addr_t tx_tail_addr;
        u32 mss;
 };