From e9777b4efcce012f09e7ca8975b29124088f5304 Mon Sep 17 00:00:00 2001 From: Tudor Ambarus Date: Tue, 25 Oct 2022 12:02:36 +0300 Subject: [PATCH] dmaengine: at_hdmac: Don't start transactions at tx_submit level commit 7176a6a8982d311e50a7c1168868d26e65bbba19 upstream. tx_submit is supposed to push the current transaction descriptor to a pending queue, waiting for issue_pending() to be called. issue_pending() must start the transfer, not tx_submit(), thus remove atc_dostart() from atc_tx_submit(). Clients of at_xdmac that assume that tx_submit() starts the transfer must be updated and call dma_async_issue_pending() if they miss to call it. The vdbg print was moved to after the lock is released. It is desirable to do the prints without the lock held if possible, and because the if statement disappears there's no reason why to do the print while holding the lock. Fixes: dc78baa2b90b ("dmaengine: at_hdmac: new driver for the Atmel AHB DMA Controller") Reported-by: Peter Rosin Signed-off-by: Tudor Ambarus Cc: stable@vger.kernel.org Link: https://lore.kernel.org/lkml/13c6c9a2-6db5-c3bf-349b-4c127ad3496a@axentia.se/ Acked-by: Nicolas Ferre Link: https://lore.kernel.org/r/20221025090306.297886-1-tudor.ambarus@microchip.com Link: https://lore.kernel.org/r/20221025090306.297886-3-tudor.ambarus@microchip.com Signed-off-by: Vinod Koul Signed-off-by: Greg Kroah-Hartman --- drivers/dma/at_hdmac.c | 14 +++----------- 1 file changed, 3 insertions(+), 11 deletions(-) diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c index 30ae361..5e7dbd9 100644 --- a/drivers/dma/at_hdmac.c +++ b/drivers/dma/at_hdmac.c @@ -691,19 +691,11 @@ static dma_cookie_t atc_tx_submit(struct dma_async_tx_descriptor *tx) spin_lock_irqsave(&atchan->lock, flags); cookie = dma_cookie_assign(tx); - if (list_empty(&atchan->active_list)) { - dev_vdbg(chan2dev(tx->chan), "tx_submit: started %u\n", - desc->txd.cookie); - atc_dostart(atchan, desc); - list_add_tail(&desc->desc_node, &atchan->active_list); - } else { - dev_vdbg(chan2dev(tx->chan), "tx_submit: queued %u\n", - desc->txd.cookie); - list_add_tail(&desc->desc_node, &atchan->queue); - } - + list_add_tail(&desc->desc_node, &atchan->queue); spin_unlock_irqrestore(&atchan->lock, flags); + dev_vdbg(chan2dev(tx->chan), "tx_submit: queued %u\n", + desc->txd.cookie); return cookie; } -- 2.7.4