This is a note to let you know that I've just added the patch titled
dmaengine: at_xdmac: Fix concurrency over xfers_list
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
dmaengine-at_xdmac-fix-concurrency-over-xfers_list.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 18deddea9184b62941395889ff7659529c877326 Mon Sep 17 00:00:00 2001
From: Tudor Ambarus <tudor.ambarus@xxxxxxxxxxxxx>
Date: Wed, 15 Dec 2021 13:01:10 +0200
Subject: dmaengine: at_xdmac: Fix concurrency over xfers_list
From: Tudor Ambarus <tudor.ambarus@xxxxxxxxxxxxx>
commit 18deddea9184b62941395889ff7659529c877326 upstream.
Since tx_submit can be called from a hard IRQ, xfers_list must be
protected with a lock to avoid concurency on the list's elements.
Since at_xdmac_handle_cyclic() is called from a tasklet, spin_lock_irq
is enough to protect from a hard IRQ.
Fixes: e1f7c9eee707 ("dmaengine: at_xdmac: creation of the atmel eXtended DMA Controller driver")
Signed-off-by: Tudor Ambarus <tudor.ambarus@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20211215110115.191749-8-tudor.ambarus@xxxxxxxxxxxxx
Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/dma/at_xdmac.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)
--- a/drivers/dma/at_xdmac.c
+++ b/drivers/dma/at_xdmac.c
@@ -1564,14 +1564,17 @@ static void at_xdmac_handle_cyclic(struc
struct at_xdmac_desc *desc;
struct dma_async_tx_descriptor *txd;
- if (!list_empty(&atchan->xfers_list)) {
- desc = list_first_entry(&atchan->xfers_list,
- struct at_xdmac_desc, xfer_node);
- txd = &desc->tx_dma_desc;
-
- if (txd->flags & DMA_PREP_INTERRUPT)
- dmaengine_desc_get_callback_invoke(txd, NULL);
+ spin_lock_irq(&atchan->lock);
+ if (list_empty(&atchan->xfers_list)) {
+ spin_unlock_irq(&atchan->lock);
+ return;
}
+ desc = list_first_entry(&atchan->xfers_list, struct at_xdmac_desc,
+ xfer_node);
+ spin_unlock_irq(&atchan->lock);
+ txd = &desc->tx_dma_desc;
+ if (txd->flags & DMA_PREP_INTERRUPT)
+ dmaengine_desc_get_callback_invoke(txd, NULL);
}
static void at_xdmac_handle_error(struct at_xdmac_chan *atchan)
Patches currently in stable-queue which might be from tudor.ambarus@xxxxxxxxxxxxx are
queue-5.4/dmaengine-at_xdmac-fix-concurrency-over-xfers_list.patch
queue-5.4/tty-serial-atmel-call-dma_async_issue_pending.patch
queue-5.4/dmaengine-at_xdmac-fix-lld-view-setting.patch
queue-5.4/dmaengine-at_xdmac-fix-at_xdmac_lld-struct-definition.patch
queue-5.4/dmaengine-at_xdmac-print-debug-message-after-realeasing-the-lock.patch
queue-5.4/dmaengine-at_xdmac-don-t-start-transactions-at-tx_submit-level.patch
queue-5.4/tty-serial-atmel-check-return-code-of-dmaengine_subm.patch
