From b30f7c8eb0780e1479a9882526e838664271f4c9 Mon Sep 17 00:00:00 2001 From: Mark Brown Date: Thu, 1 Sep 2022 13:07:32 +0100 Subject: spi: mux: Fix mux interaction with fast path optimisations The spi-mux driver is rather too clever and attempts to resubmit any message that is submitted to it to the parent controller with some adjusted callbacks. This does not play at all nicely with the fast path which now sets flags on the message indicating that it's being handled through the fast path, we see async messages flagged as being on the fast path. Ideally the spi-mux code would duplicate the message but that's rather invasive and a bit fragile in that it relies on the mux knowing which fields in the message to copy. Instead teach the core that there are controllers which can't cope with the fast path and have the mux flag itself as being such a controller, ensuring that messages going via the mux don't get partially handled via the fast path. This will reduce the performance of any spi-mux connected device since we'll now always use the thread for both the actual controller and the mux controller instead of just the actual controller but given that we were always hitting the slow path anyway it's hopefully not too much of an additional cost and it allows us to keep the fast path. Fixes: ae7d2346dc89 ("spi: Don't use the message queue if possible in spi_sync") Reported-by: Casper Andersson Tested-by: Casper Andersson Signed-off-by: Mark Brown Link: https://lore.kernel.org/r/20220901120732.49245-1-broonie@kernel.org Signed-off-by: Mark Brown --- drivers/spi/spi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/spi/spi.c') diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 8f97a3eacdea..5cbe090f7676 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -4033,7 +4033,7 @@ static int __spi_sync(struct spi_device *spi, struct spi_message *message) * guard against reentrancy from a different context. The io_mutex * will catch those cases. */ - if (READ_ONCE(ctlr->queue_empty)) { + if (READ_ONCE(ctlr->queue_empty) && !ctlr->must_async) { message->actual_length = 0; message->status = -EINPROGRESS; -- cgit From 9c9c9da7aa108e6bf952c18289527a5234e4fc59 Mon Sep 17 00:00:00 2001 From: David Jander Date: Thu, 1 Sep 2022 14:36:30 +0200 Subject: spi: spi: Fix queue hang if previous transfer failed The queue worker always needs to be kicked one final time after a transfer is done in order to transition to idle (ctlr->busy = false). Commit 69fa95905d40 ("spi: Ensure the io_mutex is held until spi_finalize_current_message()") moved this code into __spi_pump_messages(), but it was executed only if the transfer was successful. This condition check causes ctlr-busy to stay true in case of a failed transfer. This in turn causes that no new work is ever scheduled to the work queue. Fixes: 69fa95905d40 ("spi: Ensure the io_mutex is held until spi_finalize_current_message()") Reported-by: Vincent Whitchurch Signed-off-by: David Jander Link: https://lore.kernel.org/r/20220901123630.1098433-1-david@protonic.nl Signed-off-by: Mark Brown --- drivers/spi/spi.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'drivers/spi/spi.c') diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 5cbe090f7676..f7852c2c186c 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -1727,8 +1727,7 @@ static void __spi_pump_messages(struct spi_controller *ctlr, bool in_kthread) spin_unlock_irqrestore(&ctlr->queue_lock, flags); ret = __spi_pump_transfer_message(ctlr, msg, was_busy); - if (!ret) - kthread_queue_work(ctlr->kworker, &ctlr->pump_messages); + kthread_queue_work(ctlr->kworker, &ctlr->pump_messages); ctlr->cur_msg = NULL; ctlr->fallback = false; -- cgit