The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From cabb1bb60e88ccaaa122ba01862403cd44e8e8f8 Mon Sep 17 00:00:00 2001
From: Neil Armstrong narmstrong@baylibre.com Date: Mon, 26 Apr 2021 19:55:58 +0200 Subject: [PATCH] mmc: meson-gx: make replace WARN_ONCE with dev_warn_once about scatterlist offset alignment
Some drivers like ath10k can sometimg give an sg buffer with an offset whose alignment is not compatible with the Amlogic DMA descriptor engine requirements.
Simply replace with dev_warn_once() to inform user this should be fixed to avoid degraded performance.
This should be ultimately fixed in ath10k, but since it's only a performance issue the warning should be removed.
Fixes: 79ed05e329c3 ("mmc: meson-gx: add support for descriptor chain mode") Cc: stable@vger.kernel.org Reported-by: Christian Hewitt christianshewitt@gmail.com Signed-off-by: Neil Armstrong narmstrong@baylibre.com Acked-by: Martin Blumenstingl martin.blumenstingl@googlemail.com Link: https://lore.kernel.org/r/20210426175559.3110575-1-narmstrong@baylibre.com Signed-off-by: Ulf Hansson ulf.hansson@linaro.org
diff --git a/drivers/mmc/host/meson-gx-mmc.c b/drivers/mmc/host/meson-gx-mmc.c index b8b771b643cc..1c61f0f24c09 100644 --- a/drivers/mmc/host/meson-gx-mmc.c +++ b/drivers/mmc/host/meson-gx-mmc.c @@ -258,7 +258,9 @@ static void meson_mmc_get_transfer_mode(struct mmc_host *mmc, for_each_sg(data->sg, sg, data->sg_len, i) { /* check for 8 byte alignment */ if (sg->offset % 8) { - WARN_ONCE(1, "unaligned scatterlist buffer\n"); + dev_warn_once(mmc_dev(mmc), + "unaligned sg offset %u, disabling descriptor DMA for transfer\n", + sg->offset); return; } }