Messages in this thread Patch in this message |  | | | Date | Thu, 1 Nov 2007 02:51:44 +0100 (CET) | | From | Stefan Richter <> | | Subject | [PATCH] firewire: fw-sbp2: enforce read order of device generation and node ID |
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Two fixes: - There was a small window where a login or reconnect job could use an already updated card generation with an outdated node ID. We better use the fw_device.generation here, not the fw_card.generation. - Insert a memory barrier to ensure that the device generation is read before the node ID. This is to guarantee that the generation is not newer than the node ID.
A small optimization: - The target's and initiator's node IDs can be obtained from fw_device and fw_card. Dereferencing their underlying topology objects is not necessary.
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> --- drivers/firewire/fw-sbp2.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) Index: linux/drivers/firewire/fw-sbp2.c =================================================================== --- linux.orig/drivers/firewire/fw-sbp2.c +++ linux/drivers/firewire/fw-sbp2.c @@ -643,9 +643,10 @@ static void sbp2_login(struct work_struc struct sbp2_login_response response; int generation, node_id, local_node_id; - generation = device->card->generation; - node_id = device->node->node_id; - local_node_id = device->card->local_node->node_id; + generation = device->generation; + rmb(); + node_id = device->node_id; + local_node_id = device->card->node_id; if (sbp2_send_management_orb(lu, node_id, generation, SBP2_LOGIN_REQUEST, lu->lun, &response) < 0) { @@ -900,9 +901,10 @@ static void sbp2_reconnect(struct work_s struct fw_device *device = fw_device(unit->device.parent); int generation, node_id, local_node_id; - generation = device->card->generation; - node_id = device->node->node_id; - local_node_id = device->card->local_node->node_id; + generation = device->generation; + rmb(); + node_id = device->node_id; + local_node_id = device->card->node_id; if (sbp2_send_management_orb(lu, node_id, generation, SBP2_RECONNECT_REQUEST, -- Stefan Richter -=====-=-=== =-== ----= http://arcgraph.de/sr/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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