firewire: core: shrink critical section of fw_card spinlock in bm_work

Now fw_core_handle_bus_reset() and bm_work() are serialized. Some members
of fw_card are free to access in bm_work()

This commit shrinks critical section of fw_card spinlock in bm_work()

Link: https://lore.kernel.org/r/20250917000347.52369-4-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

diff --git a/drivers/firewire/core-card.c b/drivers/firewire/core-card.c
index 96495392a1f6d33ea2627688fe9ade1e9a638eea..4fcd5ce4b2cef254da5ad9ad50f5647870b27d4e 100644 (file)
--- a/drivers/firewire/core-card.c
+++ b/drivers/firewire/core-card.c
@@ -293,12 +293,8 @@ static void bm_work(struct work_struct *work)
        int expected_gap_count, generation, grace;
        bool do_reset = false;
 
-       spin_lock_irq(&card->lock);
-
-       if (card->local_node == NULL) {
-               spin_unlock_irq(&card->lock);
+       if (card->local_node == NULL)
                return;
-       }
 
        generation = card->generation;
 
@@ -354,8 +350,6 @@ static void bm_work(struct work_struct *work)
                        goto pick_me;
                }
 
-               spin_unlock_irq(&card->lock);
-
                rcode = fw_run_transaction(card, TCODE_LOCK_COMPARE_SWAP,
                                irm_id, generation, SCODE_100,
                                CSR_REGISTER_BASE + CSR_BUS_MANAGER_ID,
@@ -365,21 +359,20 @@ static void bm_work(struct work_struct *work)
                if (rcode == RCODE_GENERATION)
                        return;
 
-               spin_lock_irq(&card->lock);
-
                if (rcode == RCODE_COMPLETE) {
                        int bm_id = be32_to_cpu(data[0]);
 
                        if (generation == card->generation) {
-                               if (bm_id != BUS_MANAGER_ID_NOT_REGISTERED)
-                                       card->bm_node_id = 0xffc0 & bm_id;
-                               else
-                                       card->bm_node_id = local_id;
+                               // Used by cdev layer for "struct fw_cdev_event_bus_reset".
+                               scoped_guard(spinlock, &card->lock) {
+                                       if (bm_id != BUS_MANAGER_ID_NOT_REGISTERED)
+                                               card->bm_node_id = 0xffc0 & bm_id;
+                                       else
+                                               card->bm_node_id = local_id;
+                               }
                        }
 
                        if (bm_id != BUS_MANAGER_ID_NOT_REGISTERED) {
-                               spin_unlock_irq(&card->lock);
-
                                // Somebody else is BM.  Only act as IRM.
                                if (local_id == irm_id)
                                        allocate_broadcast_channel(card, generation);
@@ -393,7 +386,6 @@ static void bm_work(struct work_struct *work)
                         * some local problem.  Let's try again later and hope
                         * that the problem has gone away by then.
                         */
-                       spin_unlock_irq(&card->lock);
                        fw_schedule_bm_work(card, msecs_to_jiffies(125));
                        return;
                }
@@ -415,7 +407,6 @@ static void bm_work(struct work_struct *work)
                 * We weren't BM in the last generation, and the last
                 * bus reset is less than 125ms ago.  Reschedule this job.
                 */
-               spin_unlock_irq(&card->lock);
                fw_schedule_bm_work(card, msecs_to_jiffies(125));
                return;
        }
@@ -458,7 +449,6 @@ static void bm_work(struct work_struct *work)
                        if (!root_device_is_running) {
                                // If we haven't probed this device yet, bail out now
                                // and let's try again once that's done.
-                               spin_unlock_irq(&card->lock);
                                return;
                        } else if (root_device->cmc) {
                                // We will send out a force root packet for this
@@ -495,8 +485,6 @@ static void bm_work(struct work_struct *work)
        if (do_reset) {
                int card_gap_count = card->gap_count;
 
-               spin_unlock_irq(&card->lock);
-
                fw_notice(card, "phy config: new root=%x, gap_count=%d\n",
                          new_root_id, expected_gap_count);
                fw_send_phy_config(card, new_root_id, generation, expected_gap_count);
@@ -517,8 +505,6 @@ static void bm_work(struct work_struct *work)
        } else {
                struct fw_device *root_device = fw_node_get_device(root_node);
 
-               spin_unlock_irq(&card->lock);
-
                if (root_device && root_device->cmc) {
                        // Make sure that the cycle master sends cycle start packets.
                        __be32 data = cpu_to_be32(CSR_STATE_BIT_CMSTR);