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firewire: core: use mutex to coordinate concurrent calls to flush completions

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In current implementation, test_and_set_bit_lock() is used to mediate
concurrent calls of ohci_flush_iso_completions(). However, the ad-hoc
usage of atomic operations is not preferable.

This commit uses mutex_trylock() as the similar operations. The core
function is responsible for the mediation, instead of 1394 OHCI driver.

Link: https://lore.kernel.org/r/20240909140018.65289-3-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
This commit is contained in:
Takashi Sakamoto 2024-09-09 23:00:18 +09:00
parent e97fb38fa1
commit f877f1d81b
3 changed files with 24 additions and 25 deletions
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11
drivers/firewire/core-iso.c
View File

@ -157,6 +157,7 @@ struct fw_iso_context *fw_iso_context_create(struct fw_card *card,
ctx->callback.sc = callback;
ctx->callback_data = callback_data;
INIT_WORK(&ctx->work, flush_completions_work);
mutex_init(&ctx->flushing_completions_mutex);
trace_isoc_outbound_allocate(ctx, channel, speed);
trace_isoc_inbound_single_allocate(ctx, channel, header_size);
@ -173,6 +174,8 @@ void fw_iso_context_destroy(struct fw_iso_context *ctx)
trace_isoc_inbound_multiple_destroy(ctx);
ctx->card->driver->free_iso_context(ctx);
mutex_destroy(&ctx->flushing_completions_mutex);
}
EXPORT_SYMBOL(fw_iso_context_destroy);
@ -226,7 +229,7 @@ EXPORT_SYMBOL(fw_iso_context_queue_flush);
* to process the context asynchronously, fw_iso_context_schedule_flush_completions() is available
* instead.
*
* Context: Process context.
* Context: Process context due to mutex_trylock().
*/
int fw_iso_context_flush_completions(struct fw_iso_context *ctx)
{
@ -234,7 +237,11 @@ int fw_iso_context_flush_completions(struct fw_iso_context *ctx)
trace_isoc_inbound_single_flush_completions(ctx);
trace_isoc_inbound_multiple_flush_completions(ctx);
return ctx->card->driver->flush_iso_completions(ctx);
scoped_cond_guard(mutex_try, /* nothing to do */, &ctx->flushing_completions_mutex) {
return ctx->card->driver->flush_iso_completions(ctx);
}
return 0;
}
EXPORT_SYMBOL(fw_iso_context_flush_completions);

37
drivers/firewire/ohci.c
View File

@ -166,7 +166,6 @@ struct iso_context {
struct context context;
void *header;
size_t header_length;
unsigned long flushing_completions;
u32 mc_buffer_bus;
u16 mc_completed;
u16 last_timestamp;
@ -3579,31 +3578,23 @@ static void ohci_flush_queue_iso(struct fw_iso_context *base)
static int ohci_flush_iso_completions(struct fw_iso_context *base)
{
struct iso_context *ctx = container_of(base, struct iso_context, base);
int ret = 0;
if (!test_and_set_bit_lock(0, &ctx->flushing_completions)) {
// Note that tasklet softIRQ is not used to process isochronous context anymore.
context_tasklet((unsigned long)&ctx->context);
// Note that tasklet softIRQ is not used to process isochronous context anymore.
context_tasklet((unsigned long)&ctx->context);
switch (base->type) {
case FW_ISO_CONTEXT_TRANSMIT:
case FW_ISO_CONTEXT_RECEIVE:
if (ctx->header_length != 0)
flush_iso_completions(ctx, FW_ISO_CONTEXT_COMPLETIONS_CAUSE_FLUSH);
break;
case FW_ISO_CONTEXT_RECEIVE_MULTICHANNEL:
if (ctx->mc_completed != 0)
flush_ir_buffer_fill(ctx);
break;
default:
ret = -ENOSYS;
}
clear_bit_unlock(0, &ctx->flushing_completions);
smp_mb__after_atomic();
switch (base->type) {
case FW_ISO_CONTEXT_TRANSMIT:
case FW_ISO_CONTEXT_RECEIVE:
if (ctx->header_length != 0)
flush_iso_completions(ctx, FW_ISO_CONTEXT_COMPLETIONS_CAUSE_FLUSH);
return 0;
case FW_ISO_CONTEXT_RECEIVE_MULTICHANNEL:
if (ctx->mc_completed != 0)
flush_ir_buffer_fill(ctx);
return 0;
default:
return -ENOSYS;
}
return ret;
}
static const struct fw_card_driver ohci_driver = {

1
include/linux/firewire.h
View File

@ -512,6 +512,7 @@ union fw_iso_callback {
struct fw_iso_context {
struct fw_card *card;
struct work_struct work;
struct mutex flushing_completions_mutex;
int type;
int channel;
int speed;