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Subject[PATCH v2 2/2] net: macb: DMA-unmap full rx-buffer
Date
When allocating RX buffers a fixed size is used, while freeing is based
on actually received bytes, resulting in the following kernel warning
when CONFIG_DMA_API_DEBUG is enabled:
WARNING: CPU: 0 PID: 0 at lib/dma-debug.c:1051 check_unmap+0x258/0x894()
macb e000b000.ethernet: DMA-API: device driver frees DMA memory with different size [device address=0x000000002d170040] [map size=1536 bytes] [unmap size=60 bytes]
Modules linked in:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 3.14.0-rc3-xilinx-00220-g49f84081ce4f #65
[<c001516c>] (unwind_backtrace) from [<c0011df8>] (show_stack+0x10/0x14)
[<c0011df8>] (show_stack) from [<c03c775c>] (dump_stack+0x7c/0xc8)
[<c03c775c>] (dump_stack) from [<c00245cc>] (warn_slowpath_common+0x60/0x84)
[<c00245cc>] (warn_slowpath_common) from [<c0024670>] (warn_slowpath_fmt+0x2c/0x3c)
[<c0024670>] (warn_slowpath_fmt) from [<c0227d44>] (check_unmap+0x258/0x894)
[<c0227d44>] (check_unmap) from [<c0228588>] (debug_dma_unmap_page+0x64/0x70)
[<c0228588>] (debug_dma_unmap_page) from [<c02ab78c>] (gem_rx+0x118/0x170)
[<c02ab78c>] (gem_rx) from [<c02ac4d4>] (macb_poll+0x24/0x94)
[<c02ac4d4>] (macb_poll) from [<c031222c>] (net_rx_action+0x6c/0x188)
[<c031222c>] (net_rx_action) from [<c0028a28>] (__do_softirq+0x108/0x280)
[<c0028a28>] (__do_softirq) from [<c0028e8c>] (irq_exit+0x84/0xf8)
[<c0028e8c>] (irq_exit) from [<c000f360>] (handle_IRQ+0x68/0x8c)
[<c000f360>] (handle_IRQ) from [<c0008528>] (gic_handle_irq+0x3c/0x60)
[<c0008528>] (gic_handle_irq) from [<c0012904>] (__irq_svc+0x44/0x78)
Exception stack(0xc056df20 to 0xc056df68)
df20: 00000001 c0577430 00000000 c0577430 04ce8e0d 00000002 edfce238 00000000
df40: 04e20f78 00000002 c05981f4 00000000 00000008 c056df68 c0064008 c02d7658
df60: 20000013 ffffffff
[<c0012904>] (__irq_svc) from [<c02d7658>] (cpuidle_enter_state+0x54/0xf8)
[<c02d7658>] (cpuidle_enter_state) from [<c02d77dc>] (cpuidle_idle_call+0xe0/0x138)
[<c02d77dc>] (cpuidle_idle_call) from [<c000f660>] (arch_cpu_idle+0x8/0x3c)
[<c000f660>] (arch_cpu_idle) from [<c006bec4>] (cpu_startup_entry+0xbc/0x124)
[<c006bec4>] (cpu_startup_entry) from [<c053daec>] (start_kernel+0x350/0x3b0)
---[ end trace d5fdc38641bd3a11 ]---
Mapped at:
[<c0227184>] debug_dma_map_page+0x48/0x11c
[<c02ab32c>] gem_rx_refill+0x154/0x1f8
[<c02ac7b4>] macb_open+0x270/0x3e0
[<c03152e0>] __dev_open+0x7c/0xfc
[<c031554c>] __dev_change_flags+0x8c/0x140

Fixing this by passing the same size which is passed during mapping the
memory to the unmap function as well.

Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
---
v2:
- no changes
---
drivers/net/ethernet/cadence/macb.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/cadence/macb.c b/drivers/net/ethernet/cadence/macb.c
index a9c2ccfc1740..c2eccae1d550 100644
--- a/drivers/net/ethernet/cadence/macb.c
+++ b/drivers/net/ethernet/cadence/macb.c
@@ -730,7 +730,7 @@ static int gem_rx(struct macb *bp, int budget)
skb_put(skb, len);
addr = MACB_BF(RX_WADDR, MACB_BFEXT(RX_WADDR, addr));
dma_unmap_single(&bp->pdev->dev, addr,
- len, DMA_FROM_DEVICE);
+ bp->rx_buffer_size, DMA_FROM_DEVICE);

skb->protocol = eth_type_trans(skb, bp->dev);
skb_checksum_none_assert(skb);
--
1.9.0.1.g4196000


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