Commit aef6bcc0 authored by Takashi Sakamoto's avatar Takashi Sakamoto
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firewire: ohci: use workqueue to handle events of AT request/response contexts 

This commit adds a work item to handle events of 1394 OHCI AT
request/response contexts, and queues the item to the specific
workqueue. The call of struct fw_packet.callbaqck() is done in the
workqueue when receiving acknowledgement to the asynchronous packet
transferred to remote node.

Link: https://lore.kernel.org/r/20250615133253.433057-4-o-takashi@sakamocchi.jp


Signed-off-by: default avatarTakashi Sakamoto <o-takashi@sakamocchi.jp>
parent 57e6d9f8

drivers/firewire/net.c

+2 −2
Original line number Diff line number Diff line
@@ -1007,7 +1007,7 @@ static int fwnet_send_packet(struct fwnet_packet_task *ptask) 


		spin_lock_irqsave(&dev->lock, flags);



		/* If the AT tasklet already ran, we may be last user. */

		/* If the AT work item already ran, we may be last user. */

		free = (ptask->outstanding_pkts == 0 && !ptask->enqueued);

		if (!free)

			ptask->enqueued = true;
@@ -1026,7 +1026,7 @@ static int fwnet_send_packet(struct fwnet_packet_task *ptask) 


	spin_lock_irqsave(&dev->lock, flags);



	/* If the AT tasklet already ran, we may be last user. */

	/* If the AT work item already ran, we may be last user. */

	free = (ptask->outstanding_pkts == 0 && !ptask->enqueued);

	if (!free)

		ptask->enqueued = true;

drivers/firewire/ohci.c

+24 −16
Original line number Diff line number Diff line
@@ -158,7 +158,7 @@ struct context { 


	descriptor_callback_t callback;



	struct tasklet_struct tasklet;

	struct work_struct work;

};



struct iso_context {
@@ -1176,9 +1176,9 @@ static void context_retire_descriptors(struct context *ctx) 
	}

}



static void context_tasklet(unsigned long data)

static void ohci_at_context_work(struct work_struct *work)

{

	struct context *ctx = (struct context *) data;

	struct context *ctx = from_work(ctx, work, work);



	context_retire_descriptors(ctx);

}
@@ -1243,7 +1243,6 @@ static int context_init(struct context *ctx, struct fw_ohci *ohci, 
	ctx->buffer_tail = list_entry(ctx->buffer_list.next,

			struct descriptor_buffer, list);



	tasklet_init(&ctx->tasklet, context_tasklet, (unsigned long)ctx);

	ctx->callback = callback;



	/*
@@ -1524,13 +1523,17 @@ static int at_context_queue_packet(struct context *ctx, 


static void at_context_flush(struct context *ctx)

{

	tasklet_disable(&ctx->tasklet);

	// Avoid dead lock due to programming mistake.

	if (WARN_ON_ONCE(current_work() == &ctx->work))

		return;



	ctx->flushing = true;

	context_tasklet((unsigned long)ctx);

	ctx->flushing = false;

	disable_work_sync(&ctx->work);



	tasklet_enable(&ctx->tasklet);

	WRITE_ONCE(ctx->flushing, true);

	ohci_at_context_work(&ctx->work);

	WRITE_ONCE(ctx->flushing, false);



	enable_work(&ctx->work);

}



static int handle_at_packet(struct context *context,
@@ -1542,7 +1545,7 @@ static int handle_at_packet(struct context *context, 
	struct fw_ohci *ohci = context->ohci;

	int evt;



	if (last->transfer_status == 0 && !context->flushing)

	if (last->transfer_status == 0 && !READ_ONCE(context->flushing))

		/* This descriptor isn't done yet, stop iteration. */

		return 0;
@@ -1576,7 +1579,7 @@ static int handle_at_packet(struct context *context, 
		break;



	case OHCI1394_evt_missing_ack:

		if (context->flushing)

		if (READ_ONCE(context->flushing))

			packet->ack = RCODE_GENERATION;

		else {

			/*
@@ -1598,7 +1601,7 @@ static int handle_at_packet(struct context *context, 
		break;



	case OHCI1394_evt_no_status:

		if (context->flushing) {

		if (READ_ONCE(context->flushing)) {

			packet->ack = RCODE_GENERATION;

			break;

		}
@@ -2239,10 +2242,10 @@ static irqreturn_t irq_handler(int irq, void *data) 
		queue_work(ohci->card.async_wq, &ohci->ar_response_ctx.work);



	if (event & OHCI1394_reqTxComplete)

		tasklet_schedule(&ohci->at_request_ctx.tasklet);

		queue_work(ohci->card.async_wq, &ohci->at_request_ctx.work);



	if (event & OHCI1394_respTxComplete)

		tasklet_schedule(&ohci->at_response_ctx.tasklet);

		queue_work(ohci->card.async_wq, &ohci->at_response_ctx.work);



	if (event & OHCI1394_isochRx) {

		iso_event = reg_read(ohci, OHCI1394_IsoRecvIntEventClear);
@@ -2684,7 +2687,10 @@ static int ohci_cancel_packet(struct fw_card *card, struct fw_packet *packet) 
	struct driver_data *driver_data = packet->driver_data;

	int ret = -ENOENT;



	tasklet_disable_in_atomic(&ctx->tasklet);

	// Avoid dead lock due to programming mistake.

	if (WARN_ON_ONCE(current_work() == &ctx->work))

		return 0;

	disable_work_sync(&ctx->work);



	if (packet->ack != 0)

		goto out;
@@ -2703,7 +2709,7 @@ static int ohci_cancel_packet(struct fw_card *card, struct fw_packet *packet) 
	packet->callback(packet, &ohci->card, packet->ack);

	ret = 0;

 out:

	tasklet_enable(&ctx->tasklet);

	enable_work(&ctx->work);



	return ret;

}
@@ -3765,11 +3771,13 @@ static int pci_probe(struct pci_dev *dev, 
			   OHCI1394_AsReqTrContextControlSet, handle_at_packet);

	if (err < 0)

		return err;

	INIT_WORK(&ohci->at_request_ctx.work, ohci_at_context_work);



	err = context_init(&ohci->at_response_ctx, ohci,

			   OHCI1394_AsRspTrContextControlSet, handle_at_packet);

	if (err < 0)

		return err;

	INIT_WORK(&ohci->at_response_ctx.work, ohci_at_context_work);



	reg_write(ohci, OHCI1394_IsoRecvIntMaskSet, ~0);

	ohci->ir_context_channels = ~0ULL;

include/linux/firewire.h

+9 −2
Original line number Diff line number Diff line
@@ -308,8 +308,7 @@ struct fw_packet { 
	 * For successful transmission, the status code is the ack received

	 * from the destination.  Otherwise it is one of the juju-specific

	 * rcodes:  RCODE_SEND_ERROR, _CANCELLED, _BUSY, _GENERATION, _NO_ACK.

	 * The callback can be called from tasklet context and thus

	 * must never block.

	 * The callback can be called from workqueue and thus must never block.

	 */

	fw_packet_callback_t callback;

	int ack;
@@ -382,6 +381,10 @@ void __fw_send_request(struct fw_card *card, struct fw_transaction *t, int tcode 
 *

 * A variation of __fw_send_request() to generate callback for response subaction without time

 * stamp.

 *

 * The callback is invoked in the workqueue context in most cases. However, if an error is detected

 * before queueing or the destination address refers to the local node, it is invoked in the

 * current context instead.

 */

static inline void fw_send_request(struct fw_card *card, struct fw_transaction *t, int tcode,

				   int destination_id, int generation, int speed,
@@ -411,6 +414,10 @@ static inline void fw_send_request(struct fw_card *card, struct fw_transaction * 
 * @callback_data:	data to be passed to the transaction completion callback

 *

 * A variation of __fw_send_request() to generate callback for response subaction with time stamp.

 *

 * The callback is invoked in the workqueue context in most cases. However, if an error is detected

 * before queueing or the destination address refers to the local node, it is invoked in the current

 * context instead.

 */

static inline void fw_send_request_with_tstamp(struct fw_card *card, struct fw_transaction *t,

	int tcode, int destination_id, int generation, int speed, unsigned long long offset,