[core-for-CI] nvme-pci: don't use dma_alloc_noncontiguous with 0 merge boundary

[Chaitanya Kumar Borah]

From: Christoph Hellwig <hch at lst.de>

Only call into nvme_alloc_host_mem_single which uses
dma_alloc_noncontiguous when there is non-null dma merge boundary.
Without this we'll call into dma_alloc_noncontiguous for device using
dma-direct, which can work fine as long as the preferred size is below the
MAX_ORDER of the page allocator, but blows up with a warning if it is
too large.

Fixes: 63a5c7a4b4c4 ("nvme-pci: use dma_alloc_noncontigous if possible")
Reported-by: Leon Romanovsky <leon at kernel.org>
Reported-by: Chaitanya Kumar Borah <chaitanya.kumar.borah at intel.com>
Signed-off-by: Christoph Hellwig <hch at lst.de>
References: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/13227
Link: https://lore.kernel.org/linux-nvme/39a67024-2926-4a20-8feb-77dd64ab7c39@kernel.dk/T/#mfef47937b20e33aa3cc63a3af930f8a9f9baf8c2
---
 drivers/nvme/host/pci.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 4c644bb7f069..778f124c2e21 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -2172,6 +2172,7 @@ static int nvme_alloc_host_mem_multi(struct nvme_dev *dev, u64 preferred,
 
 static int nvme_alloc_host_mem(struct nvme_dev *dev, u64 min, u64 preferred)
 {
+	unsigned long dma_merge_moundary = dma_get_merge_boundary(dev->dev);
 	u64 min_chunk = min_t(u64, preferred, PAGE_SIZE * MAX_ORDER_NR_PAGES);
 	u64 hmminds = max_t(u32, dev->ctrl.hmminds * 4096, PAGE_SIZE * 2);
 	u64 chunk_size;
@@ -2180,7 +2181,7 @@ static int nvme_alloc_host_mem(struct nvme_dev *dev, u64 min, u64 preferred)
 	 * If there is an IOMMU that can merge pages, try a virtually
 	 * non-contiguous allocation for a single segment first.
 	 */
-	if (!(PAGE_SIZE & dma_get_merge_boundary(dev->dev))) {
+	if (dma_merge_moundary && (PAGE_SIZE & dma_merge_moundary) == 0) {
 		if (!nvme_alloc_host_mem_single(dev, preferred))
 			return 0;
 	}
-- 
2.25.1