netdev - [PATCH 6/7] ALSA: memalloc: don't pass bogus GFP_ flags to dma_alloc

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Message-Id: <20221113163535.884299-7-hch@lst.de>
Date:   Sun, 13 Nov 2022 17:35:34 +0100
From:   Christoph Hellwig <hch@....de>
To:     Dennis Dalessandro <dennis.dalessandro@...nelisnetworks.com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Alexandra Winter <wintera@...ux.ibm.com>,
        Wenjia Zhang <wenjia@...ux.ibm.com>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        Jaroslav Kysela <perex@...ex.cz>,
        Takashi Iwai <tiwai@...e.com>,
        Russell King <linux@...linux.org.uk>,
        Robin Murphy <robin.murphy@....com>
Cc:     linux-arm-kernel@...ts.infradead.org, linux-rdma@...r.kernel.org,
        iommu@...ts.linux.dev, linux-media@...r.kernel.org,
        netdev@...r.kernel.org, linux-s390@...r.kernel.org,
        alsa-devel@...a-project.org
Subject: [PATCH 6/7] ALSA: memalloc: don't pass bogus GFP_ flags to dma_alloc_*

dma_alloc_coherent/dma_alloc_wc is an opaque allocator that only uses
the GFP_ flags for allocation context control.  Don't pass __GFP_COMP
which makes no sense for an allocation that can't in any way be
converted to a page pointer.

Note that for dma_alloc_noncoherent and dma_alloc_noncontigous in
combination with the DMA mmap helpers __GFP_COMP looks sketchy as well,
so I would suggest to drop that as well after a careful audit.

Signed-off-by: Christoph Hellwig <hch@....de>
---
 sound/core/memalloc.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/sound/core/memalloc.c b/sound/core/memalloc.c
index 03cffe7713667..fe03cf796e8bb 100644
--- a/sound/core/memalloc.c
+++ b/sound/core/memalloc.c
@@ -20,7 +20,6 @@
 
 #define DEFAULT_GFP \
 	(GFP_KERNEL | \
-	 __GFP_COMP |    /* compound page lets parts be mapped */ \
 	 __GFP_RETRY_MAYFAIL | /* don't trigger OOM-killer */ \
 	 __GFP_NOWARN)   /* no stack trace print - this call is non-critical */
 
@@ -542,7 +541,7 @@ static void *snd_dma_noncontig_alloc(struct snd_dma_buffer *dmab, size_t size)
 	void *p;
 
 	sgt = dma_alloc_noncontiguous(dmab->dev.dev, size, dmab->dev.dir,
-				      DEFAULT_GFP, 0);
+				      DEFAULT_GFP | __GFP_COMP, 0);
 	if (!sgt) {
 #ifdef CONFIG_SND_DMA_SGBUF
 		if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC_SG)
@@ -810,7 +809,7 @@ static void *snd_dma_noncoherent_alloc(struct snd_dma_buffer *dmab, size_t size)
 	void *p;
 
 	p = dma_alloc_noncoherent(dmab->dev.dev, size, &dmab->addr,
-				  dmab->dev.dir, DEFAULT_GFP);
+				  dmab->dev.dir, DEFAULT_GFP | __GFP_COMP);
 	if (p)
 		dmab->dev.need_sync = dma_need_sync(dmab->dev.dev, dmab->addr);
 	return p;
-- 
2.30.2