[ Upstream commit e51183be1fa96dc6d3cd11b3c25a0f595807315e ] According to the module parameter description for sgl_threshold, a value of 0 means that SGLs are disabled. If SGLs are disabled, we should respect that, even for the case where the request is made up of a single physical segment. Fixes: 297910571f08 ("nvme-pci: optimize mapping single segment requests using SGLs") Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Sasha Levin <sashal@kernel.org>