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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Christian Hewitt <christianshewitt@gmail.com>,
        Neil Armstrong <narmstrong@baylibre.com>,
        Ulf Hansson <ulf.hansson@linaro.org>
Subject: [PATCH 5.12 086/127] mmc: meson-gx: also check SD_IO_RW_EXTENDED for scatterlist size alignment
Date:   Mon, 24 May 2021 17:26:43 +0200
Message-Id: <20210524152337.767670885@linuxfoundation.org>
In-Reply-To: <20210524152334.857620285@linuxfoundation.org>
References: <20210524152334.857620285@linuxfoundation.org>
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From: Neil Armstrong <narmstrong@baylibre.com>

commit 9b81354d7ebc1fd17f666a168dcabf27dae290bd upstream.

The brcmfmac driver can generate a scatterlist from a skb with each packets
not aligned to the block size. This is not supported by the Amlogic Descriptor
dma engine where each descriptor must match a multiple of the block size.

The sg list is valid, since the sum of the sg buffers is a multiple of the
block size, but we must discard those when in SD_IO_RW_EXTENDED mode since
SDIO block mode can be used under the hood even with data->blocks == 1.

Those transfers are very rare, thus can be replaced by a bounce buffer
without real performance loss.

Fixes: 7412dee9f1fd ("mmc: meson-gx: replace WARN_ONCE with dev_warn_once about scatterlist size alignment in block mode")
Cc: stable@vger.kernel.org
Reported-by: Christian Hewitt <christianshewitt@gmail.com>
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Link: https://lore.kernel.org/r/20210426175559.3110575-2-narmstrong@baylibre.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/mmc/host/meson-gx-mmc.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/mmc/host/meson-gx-mmc.c
+++ b/drivers/mmc/host/meson-gx-mmc.c
@@ -236,7 +236,8 @@ static void meson_mmc_get_transfer_mode(
 	if (host->dram_access_quirk)
 		return;
 
-	if (data->blocks > 1) {
+	/* SD_IO_RW_EXTENDED (CMD53) can also use block mode under the hood */
+	if (data->blocks > 1 || mrq->cmd->opcode == SD_IO_RW_EXTENDED) {
 		/*
 		 * In block mode DMA descriptor format, "length" field indicates
 		 * number of blocks and there is no way to pass DMA size that