[PATCH] mmc: meson: move mmc_request_done() call to irq thread

[Martin Hundebøll]

From: Martin Hundebøll <mhu at rtx.dk>

The call to mmc_request_done() can schedule, so it cannot be called from
irq context. Wake the irq thread if it needs to be called, and call it
from there instead.

Fixes the following kernel bug, which appears when running an RT patched
kernel on the AmLogic Meson AXG A113X SoC:
[   11.111407] BUG: scheduling while atomic: kworker/0:1H/75/0x00010001
[   11.111438] Modules linked in:
[   11.111451] CPU: 0 PID: 75 Comm: kworker/0:1H Not tainted 6.4.0-rc3-rt2-rtx-00081-gfd07f41ed6b4-dirty #1
[   11.111461] Hardware name: RTX AXG A113X Linux Platform Board (DT)
[   11.111469] Workqueue: kblockd blk_mq_run_work_fn
[   11.111492] Call trace:
[   11.111497]  dump_backtrace+0xac/0xe8
[   11.111510]  show_stack+0x18/0x28
[   11.111518]  dump_stack_lvl+0x48/0x60
[   11.111530]  dump_stack+0x18/0x24
[   11.111537]  __schedule_bug+0x4c/0x68
[   11.111548]  __schedule+0x80/0x574
[   11.111558]  schedule_loop+0x2c/0x50
[   11.111567]  schedule_rtlock+0x14/0x20
[   11.111576]  rtlock_slowlock_locked+0x468/0x730
[   11.111587]  rt_spin_lock+0x40/0x64
[   11.111596]  __wake_up_common_lock+0x5c/0xc4
[   11.111610]  __wake_up+0x18/0x24
[   11.111620]  mmc_blk_mq_req_done+0x68/0x138
[   11.111633]  mmc_request_done+0x104/0x118
[   11.111644]  meson_mmc_request_done+0x38/0x48
[   11.111654]  meson_mmc_irq+0x128/0x1f0
[   11.111663]  __handle_irq_event_percpu+0x70/0x114
[   11.111674]  handle_irq_event_percpu+0x18/0x4c
[   11.111683]  handle_irq_event+0x80/0xb8
[   11.111691]  handle_fasteoi_irq+0xa4/0x120
[   11.111704]  handle_irq_desc+0x20/0x38
[   11.111712]  generic_handle_domain_irq+0x1c/0x28
[   11.111721]  gic_handle_irq+0x8c/0xa8
[   11.111735]  call_on_irq_stack+0x24/0x4c
[   11.111746]  do_interrupt_handler+0x88/0x94
[   11.111757]  el1_interrupt+0x34/0x64
[   11.111769]  el1h_64_irq_handler+0x18/0x24
[   11.111779]  el1h_64_irq+0x64/0x68
[   11.111786]  __add_wait_queue+0x0/0x4c
[   11.111795]  mmc_blk_rw_wait+0x84/0x118
[   11.111804]  mmc_blk_mq_issue_rq+0x5c4/0x654
[   11.111814]  mmc_mq_queue_rq+0x194/0x214
[   11.111822]  blk_mq_dispatch_rq_list+0x3ac/0x528
[   11.111834]  __blk_mq_sched_dispatch_requests+0x340/0x4d0
[   11.111847]  blk_mq_sched_dispatch_requests+0x38/0x70
[   11.111858]  blk_mq_run_work_fn+0x3c/0x70
[   11.111865]  process_one_work+0x17c/0x1f0
[   11.111876]  worker_thread+0x1d4/0x26c
[   11.111885]  kthread+0xe4/0xf4
[   11.111894]  ret_from_fork+0x10/0x20

Fixes: 51c5d8447bd71b ("MMC: meson: initial support for GX platforms")
Cc: stable at vger.kernel.org
Signed-off-by: Martin Hundebøll <martin at geanix.com>
---
 drivers/mmc/host/meson-gx-mmc.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c
index b8514d9d5e736..77b2c23084566 100644
--- a/drivers/mmc/host/meson-gx-mmc.c
+++ b/drivers/mmc/host/meson-gx-mmc.c
@@ -991,11 +991,8 @@ static irqreturn_t meson_mmc_irq(int irq, void *dev_id)
 
 		if (data && !cmd->error)
 			data->bytes_xfered = data->blksz * data->blocks;
-		if (meson_mmc_bounce_buf_read(data) ||
-		    meson_mmc_get_next_command(cmd))
-			ret = IRQ_WAKE_THREAD;
-		else
-			ret = IRQ_HANDLED;
+
+		ret = IRQ_WAKE_THREAD;
 	}
 
 out:
@@ -1007,9 +1004,6 @@ static irqreturn_t meson_mmc_irq(int irq, void *dev_id)
 		writel(start, host->regs + SD_EMMC_START);
 	}
 
-	if (ret == IRQ_HANDLED)
-		meson_mmc_request_done(host->mmc, cmd->mrq);
-
 	return ret;
 }
 
@@ -1040,6 +1034,13 @@ static irqreturn_t meson_mmc_irq_thread(int irq, void *dev_id)
 	if (WARN_ON(!cmd))
 		return IRQ_NONE;
 
+	if (!meson_mmc_bounce_buf_read(cmd->data) &&
+	    !meson_mmc_get_next_command(cmd)) {
+		meson_mmc_request_done(host->mmc, cmd->mrq);
+
+		return IRQ_HANDLED;
+	}
+
 	if (cmd->error) {
 		meson_mmc_wait_desc_stop(host);
 		meson_mmc_request_done(host->mmc, cmd->mrq);
-- 
2.40.1