From: Takashi Sakamoto Date: Sun, 15 Jun 2025 13:32:53 +0000 (+0900) Subject: firewire: ohci: use workqueue to handle events of AT request/response contexts X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=aef6bcc0f278eba408751f8b3e0beae992e9faec;p=thirdparty%2Fkernel%2Flinux.git 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: Takashi Sakamoto --- diff --git a/drivers/firewire/net.c b/drivers/firewire/net.c index 1bf0e15c15408..6d64467135395 100644 --- a/drivers/firewire/net.c +++ b/drivers/firewire/net.c @@ -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; diff --git a/drivers/firewire/ohci.c b/drivers/firewire/ohci.c index 68317b5a64a74..709a714fd5c8c 100644 --- a/drivers/firewire/ohci.c +++ b/drivers/firewire/ohci.c @@ -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; diff --git a/include/linux/firewire.h b/include/linux/firewire.h index c55b8e30e700d..cceb70415ed2a 100644 --- a/include/linux/firewire.h +++ b/include/linux/firewire.h @@ -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,