diff options
| author | Stefan Richter <stefanr@s5r6.in-berlin.de> | 2008-01-25 18:57:41 +0100 |
|---|---|---|
| committer | Stefan Richter <stefanr@s5r6.in-berlin.de> | 2008-01-30 22:22:27 +0100 |
| commit | b5d2a5e04e6a26cb3f77af8cbc31e74c361d706c (patch) | |
| tree | cfc3b2dc141f643bcf6ef065cca802340b335799 /drivers/firewire/fw-device.c | |
| parent | cf5a56ac8083dd04ffe8b9b2ec7895e9bcff44bc (diff) | |
firewire: enforce access order between generation and node ID, fix "giving up on config rom"
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 <stefanr@s5r6.in-berlin.de>
Reviewed by Nick Piggin <nickpiggin@yahoo.com.au>.
Verified to fix 'giving up on config rom' issues on multiple system and
drive combinations that were previously affected.
Signed-off-by: Jarod Wilson <jwilson@redhat.com>
Signed-off-by: Kristian Høgsberg <krh@redhat.com>
Diffstat (limited to 'drivers/firewire/fw-device.c')
| -rw-r--r-- | drivers/firewire/fw-device.c | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/drivers/firewire/fw-device.c b/drivers/firewire/fw-device.c index 56681b3b297b..872df2238609 100644 --- a/drivers/firewire/fw-device.c +++ b/drivers/firewire/fw-device.c @@ -27,6 +27,7 @@ #include <linux/idr.h> #include <linux/rwsem.h> #include <asm/semaphore.h> +#include <asm/system.h> #include <linux/ctype.h> #include "fw-transaction.h" #include "fw-topology.h" @@ -182,9 +183,14 @@ static void fw_device_release(struct device *dev) int fw_device_enable_phys_dma(struct fw_device *device) { + int generation = device->generation; + + /* device->node_id, accessed below, must not be older than generation */ + smp_rmb(); + return device->card->driver->enable_phys_dma(device->card, device->node_id, - device->generation); + generation); } EXPORT_SYMBOL(fw_device_enable_phys_dma); @@ -389,12 +395,16 @@ static int read_rom(struct fw_device *device, int index, u32 * data) struct read_quadlet_callback_data callback_data; struct fw_transaction t; u64 offset; + int generation = device->generation; + + /* device->node_id, accessed below, must not be older than generation */ + smp_rmb(); init_completion(&callback_data.done); offset = 0xfffff0000400ULL + index * 4; fw_send_request(device->card, &t, TCODE_READ_QUADLET_REQUEST, - device->node_id, device->generation, device->max_speed, + device->node_id, generation, device->max_speed, offset, NULL, 4, complete_transaction, &callback_data); wait_for_completion(&callback_data.done); @@ -801,6 +811,7 @@ void fw_node_event(struct fw_card *card, struct fw_node *node, int event) device = node->data; device->node_id = node->node_id; + smp_wmb(); /* update node_id before generation */ device->generation = card->generation; if (atomic_read(&device->state) == FW_DEVICE_RUNNING) { PREPARE_DELAYED_WORK(&device->work, fw_device_update); |