• J
    cifs: on CONFIG_HIGHMEM machines, limit the rsize/wsize to the kmap space · 3ae629d9
    Jeff Layton 提交于
    We currently rely on being able to kmap all of the pages in an async
    read or write request. If you're on a machine that has CONFIG_HIGHMEM
    set then that kmap space is limited, sometimes to as low as 512 slots.
    
    With 512 slots, we can only support up to a 2M r/wsize, and that's
    assuming that we can get our greedy little hands on all of them. There
    are other users however, so it's possible we'll end up stuck with a
    size that large.
    
    Since we can't handle a rsize or wsize larger than that currently, cap
    those options at the number of kmap slots we have. We could consider
    capping it even lower, but we currently default to a max of 1M. Might as
    well allow those luddites on 32 bit arches enough rope to hang
    themselves.
    
    A more robust fix would be to teach the send and receive routines how
    to contend with an array of pages so we don't need to marshal up a kvec
    array at all. That's a fairly significant overhaul though, so we'll need
    this limit in place until that's ready.
    
    Cc: <stable@vger.kernel.org>
    Reported-by: NJian Li <jiali@redhat.com>
    Signed-off-by: NJeff Layton <jlayton@redhat.com>
    Signed-off-by: NSteve French <smfrench@gmail.com>
    3ae629d9
connect.c 115.6 KB