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
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: 4a71df50047f ("qeth: new qeth device driver")
Signed-off-by: Julian Wiedmann <email@example.com>
Signed-off-by: David S. Miller <firstname.lastname@example.org>
4 files changed