netdev - [PATCH 2/2] m68k: return NULL from dma_alloc

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Message-Id: <20221121095631.216209-3-hch@lst.de>
Date:   Mon, 21 Nov 2022 10:56:31 +0100
From:   Christoph Hellwig <hch@....de>
To:     Greg Ungerer <gerg@...ux-m68k.org>,
        Joakim Zhang <qiangqing.zhang@....com>
Cc:     Geert Uytterhoeven <geert@...ux-m68k.org>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        linux-m68k@...ts.linux-m68k.org, uclinux-dev@...inux.org,
        netdev@...r.kernel.org
Subject: [PATCH 2/2] m68k: return NULL from dma_alloc_coherent for nommu or coldfire

m68knommu and coldfire platforms can't support allocating coherent DMA
memory.  Instead of just returning noncoherent memory, just fail the
allocation.

Signed-off-by: Christoph Hellwig <hch@....de>
---
 arch/m68k/kernel/dma.c | 14 ++------------
 1 file changed, 2 insertions(+), 12 deletions(-)

diff --git a/arch/m68k/kernel/dma.c b/arch/m68k/kernel/dma.c
index 2e192a5df949b..63618fce5dc7f 100644
--- a/arch/m68k/kernel/dma.c
+++ b/arch/m68k/kernel/dma.c
@@ -37,23 +37,13 @@ pgprot_t pgprot_dmacoherent(pgprot_t prot)
 void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
 		gfp_t gfp, unsigned long attrs)
 {
-	void *ret;
-
-	if (dev == NULL || (*dev->dma_mask < 0xffffffff))
-		gfp |= GFP_DMA;
-	ret = (void *)__get_free_pages(gfp, get_order(size));
-
-	if (ret != NULL) {
-		memset(ret, 0, size);
-		*dma_handle = virt_to_phys(ret);
-	}
-	return ret;
+	return NULL;
 }
 
 void arch_dma_free(struct device *dev, size_t size, void *vaddr,
 		dma_addr_t dma_handle, unsigned long attrs)
 {
-	free_pages((unsigned long)vaddr, get_order(size));
+	WARN_ON_ONCE(1);
 }
 
 #endif /* CONFIG_MMU && !CONFIG_COLDFIRE */
-- 
2.30.2