linux-kernel - [PATCH 5.4 221/434] ALSA: pcm: Fix missing check of the new non-cached buffer type

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Message-Id: <20191229172716.523417491@linuxfoundation.org>
Date:   Sun, 29 Dec 2019 18:24:34 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Takashi Iwai <tiwai@...e.de>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.4 221/434] ALSA: pcm: Fix missing check of the new non-cached buffer type

From: Takashi Iwai <tiwai@...e.de>

[ Upstream commit 6111fd2370eecae9f11bfdc08ba097e0b51fcfd3 ]

The check for the mmap support via hw_support_mmap() function misses
the case where the device is with SNDRV_DMA_TYPE_DEV_UC, which should
have been treated equally as SNDRV_DMA_TYPE_DEV.  Let's fix it.

Note that this bug doesn't hit any practical problem, because
SNDRV_DMA_TYPE_DEV_UC is used only for x86-specific drivers
(snd-hda-intel and snd-intel8x0) for the specific platforms that need
the non-cached buffers.  And, on such platforms, hw_support_mmap()
already returns true in anyway.  That's the reason I didn't put
Cc-to-stable mark here.  This is only for any theoretical future
extension.

Fixes: 425da159707b ("ALSA: pcm: use dma_can_mmap() to check if a device supports dma_mmap_*")
Fixes: 42e748a0b325 ("ALSA: memalloc: Add non-cached buffer type")
Link: https://lore.kernel.org/r/20191104101115.27311-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@...e.de>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 sound/core/pcm_native.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sound/core/pcm_native.c b/sound/core/pcm_native.c
index 91c6ad58729f..c3a139436ac2 100644
--- a/sound/core/pcm_native.c
+++ b/sound/core/pcm_native.c
@@ -222,7 +222,8 @@ static bool hw_support_mmap(struct snd_pcm_substream *substream)
 		return false;
 
 	if (substream->ops->mmap ||
-	    substream->dma_buffer.dev.type != SNDRV_DMA_TYPE_DEV)
+	    (substream->dma_buffer.dev.type != SNDRV_DMA_TYPE_DEV &&
+	     substream->dma_buffer.dev.type != SNDRV_DMA_TYPE_DEV_UC))
 		return true;
 
 	return dma_can_mmap(substream->dma_buffer.dev.dev);
-- 
2.20.1