swiotlb: suppress warning when __GFP_NOWARN is set

commit d0bc0c2a31c95002d37c3cc511ffdcab851b3256 upstream.

TTM tries to allocate coherent memory in chunks of 2MB first to improve
TLB efficiency and falls back to allocating 4K pages if that fails.

Suppress the warning when the 2MB allocations fails since there is a
valid fall back path.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reported-by: Mike Galbraith <efault@gmx.de>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Bug: https://bugs.freedesktop.org/show_bug.cgi?id=104082
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index 8c6c83e..20df2fd 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -585,7 +585,7 @@
 
 not_found:
 	spin_unlock_irqrestore(&io_tlb_lock, flags);
-	if (printk_ratelimit())
+	if (!(attrs & DMA_ATTR_NO_WARN) && printk_ratelimit())
 		dev_warn(hwdev, "swiotlb buffer is full (sz: %zd bytes)\n", size);
 	return SWIOTLB_MAP_ERROR;
 found:
@@ -712,6 +712,7 @@
 swiotlb_alloc_coherent(struct device *hwdev, size_t size,
 		       dma_addr_t *dma_handle, gfp_t flags)
 {
+	bool warn = !(flags & __GFP_NOWARN);
 	dma_addr_t dev_addr;
 	void *ret;
 	int order = get_order(size);
@@ -737,8 +738,8 @@
 		 * GFP_DMA memory; fall back on map_single(), which
 		 * will grab memory from the lowest available address range.
 		 */
-		phys_addr_t paddr = map_single(hwdev, 0, size,
-					       DMA_FROM_DEVICE, 0);
+		phys_addr_t paddr = map_single(hwdev, 0, size, DMA_FROM_DEVICE,
+					       warn ? 0 : DMA_ATTR_NO_WARN);
 		if (paddr == SWIOTLB_MAP_ERROR)
 			goto err_warn;
 
@@ -768,9 +769,11 @@
 	return ret;
 
 err_warn:
-	pr_warn("swiotlb: coherent allocation failed for device %s size=%zu\n",
-		dev_name(hwdev), size);
-	dump_stack();
+	if (warn && printk_ratelimit()) {
+		pr_warn("swiotlb: coherent allocation failed for device %s size=%zu\n",
+			dev_name(hwdev), size);
+		dump_stack();
+	}
 
 	return NULL;
 }