s390/qeth: implement smarter resizing of the RX buffer pool
The RX buffer pool is allocated in qeth_alloc_qdio_queues(). A subsequent pool resizing is then handled in a very simple way: first free the current pool, then allocate a new pool of the requested size. There's two ways where this can go wrong: 1. if the resize action happens _before_ the initial pool was allocated, then a subsequent initialization will call qeth_alloc_qdio_queues() and fill the pool with a second(!) set of pages. We consume twice the planned amount of memory. This is easy to fix - just skip the resizing if the queues haven't been allocated yet. 2. if the initial pool was created by qeth_alloc_qdio_queues() but a subsequent resizing fails, then the device has no(!) RX buffer pool. The next initialization will _not_ call qeth_alloc_qdio_queues(), and attempting to back the RX buffers with pages in qeth_init_qdio_queues() will fail. Not very difficult to fix either - instead of re-allocating the whole pool, just allocate/free as many entries to match the desired size. Fixes: 4a71df50 ("qeth: new qeth device driver") Signed-off-by:Julian Wiedmann <jwi@linux.ibm.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
parent
0f75e149
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