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firewire: core: reduce critical section duration in pre-processing of isoc resource management in cdev

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It is preferable for the critical section to be as small as possible.
Current implementation of iso_resource_auto_work() function uses a
spinlock to control concurrent access to members of fw_card, fw_device,
iso_resource_auto structures, however the locking duration could be
reduced.

This commit refactors to shorten that duration.

Link: https://lore.kernel.org/r/20260501135823.241940-2-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
This commit is contained in:
Takashi Sakamoto 2026-05-01 22:58:20 +09:00
parent 6dbe7653fa
commit 834b33f9c9
1 changed files with 19 additions and 15 deletions
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34
drivers/firewire/core-cdev.c
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@ -1329,32 +1329,36 @@ static void iso_resource_auto_work(struct work_struct *work)
struct iso_resource_auto *r = from_work(r, work, work.work);
struct client *client = r->client;
unsigned long index = r->resource.handle;
int generation, channel, bandwidth, todo;
int current_generation, resource_generation, channel, bandwidth, todo;
u64 reset_jiffies;
bool skip, free, success;
scoped_guard(spinlock_irq, &client->lock) {
generation = client->device->generation;
reset_jiffies = client->device->card->reset_jiffies;
current_generation = client->device->generation;
resource_generation = r->params.generation;
r->params.generation = current_generation;
todo = r->todo;
// Allow 1000ms grace period for other reallocations.
if (todo == ISO_RES_AUTO_ALLOC &&
time_is_after_jiffies64(client->device->card->reset_jiffies + secs_to_jiffies(1))) {
schedule_iso_resource_auto(r, msecs_to_jiffies(333));
skip = true;
} else {
// We could be called twice within the same generation.
skip = todo == ISO_RES_AUTO_REALLOC &&
r->params.generation == generation;
}
free = todo == ISO_RES_AUTO_DEALLOC;
r->params.generation = generation;
}
// Allow 1000ms grace period for other reallocations.
if (todo == ISO_RES_AUTO_ALLOC &&
time_is_after_jiffies64(reset_jiffies + secs_to_jiffies(1))) {
schedule_iso_resource_auto(r, msecs_to_jiffies(333));
skip = true;
} else {
// We could be called twice within the same generation.
skip = todo == ISO_RES_AUTO_REALLOC &&
resource_generation == current_generation;
}
free = todo == ISO_RES_AUTO_DEALLOC;
if (skip)
goto out;
bandwidth = r->params.bandwidth;
fw_iso_resource_manage(client->device->card, generation,
fw_iso_resource_manage(client->device->card, current_generation,
r->params.channels, &channel, &bandwidth,
todo == ISO_RES_AUTO_ALLOC ||
todo == ISO_RES_AUTO_REALLOC);