net/sonic: Fix receive buffer replenishment
As soon as the driver is finished with a receive buffer it allocs a new one and overwrites the corresponding RRA entry with a new buffer pointer. Problem is, the buffer pointer is split across two word-sized registers. It can't be updated in one atomic store. So this operation races with the chip while it stores received packets and advances its RRP register. This could result in memory corruption by a DMA write. Avoid this problem by adding buffers only at the location given by the RWP register, in accordance with the National Semiconductor datasheet. Re-factor this code into separate functions to calculate a RRA pointer and to update the RWP. Fixes: efcce839 ("[PATCH] macsonic/jazzsonic network drivers update") Tested-by:Stan Johnson <userm57@yahoo.com> Signed-off-by:
Finn Thain <fthain@telegraphics.com.au> Signed-off-by:
David S. Miller <davem@davemloft.net>
parent
94b16634
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