Doug / smarc-fsl-linux-kernel

14 Jul, 2008

1 commit

  • 792a61021   firewire: fix race of bus reset with request transmission ... Browse Code »

    Reported by Jay Fenlason: A bus reset tasklet may call
    fw_flush_transactions and touch transactions (call their callback which
    will free them) while the context which submitted the transaction is
    still inserting it into the transmission queue.

    A simple solution to this problem is to _not_ "flush" the transactions
    because of a bus reset (complete the transcations as 'cancelled'). They
    will now simply time out (completed as 'cancelled' by the split-timeout
    timer).

    Jay Fenlason thought of this fix too but I was quicker to type it out.
    :-)

    Background:
    Contexts which access an instance of struct fw_transaction are:
    1. the submitter, until it inserted the packet which is embedded in the
    transaction into the AT req DMA,
    2. the AsReqTrContext tasklet when the request packet was acked by the
    responder node or transmission to the responder failed,
    3. the AsRspRcvContext tasklet when it found a request which matched
    an incoming response,
    4. the card->flush_timer when it picks up timed-out transactions to
    cancel them,
    5. the bus reset tasklet when it cancels transactions (this access is
    eliminated by this patch),
    6. a process which shuts down an fw_card (unregisters it from fw-core
    when the controller is unbound from fw-ohci) --- although in this
    case there shouldn't really be any transactions anymore because we
    wait until all card users finished their business with the card.

    All of these contexts run concurrently (except for the 6th, presumably).
    The 1st is safe against the 2nd and 3rd because of the way how a request
    packet is carefully submitted to the hardware. A race between 2nd and
    3rd has been fixed a while ago (bug 9617). The 4th is almost safe
    against 1st, 2nd, 3rd; there are issues with it if huge scheduling
    latencies occur, to be fixed separately. The 5th looks safe against
    2nd, 3rd, and 4th but is unsafe against 1st. Maybe this could be fixed
    with an explicit state variable in struct fw_transaction. But this
    would require fw_transaction to be rewritten as only dynamically
    allocatable object with reference counting --- not a good solution if we
    also can simply kill this 5th accessing context (replace it by the 4th).

    Signed-off-by: Stefan Richter

    Stefan Richter
     

18 Apr, 2008

2 commits

  • 25b1c3d88   firewire: fix synchronization of gap counts ... Browse Code »

    Fix: The fact that nodes had different gap counts would be overlooked
    if the bus manager code would pick gap count 63 because of beta
    repeaters or because of very large hop counts. In this case, the bus
    manager code would miss that it actually has to send the PHY config
    packet with gap count 63.

    Related trivial changes: Use bool for an int used as bool, touch up
    some comments.

    Signed-off-by: Stefan Richter

    Stefan Richter
     
  • c9755e14a   firewire: reread config ROM when device reset the bus ... Browse Code »

    When a device changes its configuration ROM, it announces this with a
    bus reset. firewire-core has to check which node initiated a bus reset
    and whether any unit directories went away or were added on this node.

    Tested with an IOI FWB-IDE01AB which has its link-on bit set if bus
    power is available but does not respond to ROM read requests if self
    power is off. This implements
    - recognition of the units if self power is switched on after fw-core
    gave up the initial attempt to read the config ROM,
    - shutdown of the units when self power is switched off.

    Also tested with a second PC running Linux/ieee1394. When the eth1394
    driver is inserted and removed on that node, fw-core now notices the
    addition and removal of the IPv4 unit on the ieee1394 node.

    Signed-off-by: Stefan Richter

    Stefan Richter
     

14 Mar, 2008

1 commit

02 Mar, 2008

1 commit

  • 15803478f   firewire: potentially invalid pointers used in fw_card_bm_work ... Browse Code »

    The bus management workqueue job was in danger to dereference NULL
    pointers. Also, after having temporarily lifted card->lock, a few node
    pointers and a device pointer may have become invalid.

    Add NULL pointer checks and get the necessary references. Also, move
    card->local_node out of fw_card_bm_work's sight during shutdown of the
    card.

    Signed-off-by: Stefan Richter
    Signed-off-by: Jarod Wilson

    Stefan Richter
     

31 Jan, 2008

1 commit

  • b5d2a5e04   firewire: enforce access order between generation and node ID, fix "giving up on config rom" ... Browse Code »

    fw_device.node_id and fw_device.generation are accessed without mutexes.
    We have to ensure that all readers will get to see node_id updates
    before generation updates.

    Fixes an inability to recognize devices after "giving up on config rom",
    https://bugzilla.redhat.com/show_bug.cgi?id=429950

    Signed-off-by: Stefan Richter

    Reviewed by Nick Piggin .

    Verified to fix 'giving up on config rom' issues on multiple system and
    drive combinations that were previously affected.

    Signed-off-by: Jarod Wilson
    Signed-off-by: Kristian Høgsberg

    Stefan Richter
     

17 Oct, 2007

2 commits

10 Jul, 2007

3 commits

11 May, 2007

5 commits

29 Mar, 2007

1 commit

10 Mar, 2007

10 commits