From: Takashi Iwai <tiwai@suse.de>
Date: Sun, 15 Apr 2018 09:08:07 +0000 (+0200)
Subject: dma-direct: don't retry allocation for no-op GFP_DMA
X-Git-Tag: v4.17-rc3~37^2~2
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=504a918e6714b551b7b39940dbab32610fafa1fe;p=nvme.git

dma-direct: don't retry allocation for no-op GFP_DMA

When an allocation with lower dma_coherent mask fails, dma_direct_alloc()
retries the allocation with GFP_DMA.  But, this is useless for
architectures that hav no ZONE_DMA.

Fix it by adding the check of CONFIG_ZONE_DMA before retrying the
allocation.

Fixes: 95f183916d4b ("dma-direct: retry allocations using GFP_DMA for small masks")
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
---

diff --git a/lib/dma-direct.c b/lib/dma-direct.c
index c0bba30fef0a..bbfb229aa067 100644
--- a/lib/dma-direct.c
+++ b/lib/dma-direct.c
@@ -84,7 +84,8 @@ again:
 		__free_pages(page, page_order);
 		page = NULL;
 
-		if (dev->coherent_dma_mask < DMA_BIT_MASK(32) &&
+		if (IS_ENABLED(CONFIG_ZONE_DMA) &&
+		    dev->coherent_dma_mask < DMA_BIT_MASK(32) &&
 		    !(gfp & GFP_DMA)) {
 			gfp = (gfp & ~GFP_DMA32) | GFP_DMA;
 			goto again;