nvme: add quirk to force medium priority for SQ creation

Some P3100 drives have a bug where they think WRRU (weighted round robin)
is always enabled, even though the host doesn't set it. Since they think
it's enabled, they also look at the submission queue creation priority. We
used to set that to MEDIUM by default, but that was removed in commit
81c1cd9. This causes various issues on that drive. Add a quirk to
still set MEDIUM priority for that controller.

Fixes: 81c1cd9 ("nvme/pci: Don't set reserved SQ create flags")
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Keith Busch <keith.busch@intel.com>

drivers/nvme/host/nvme.h

@@ -84,6 +84,11 @@ enum nvme_quirks {
 	 * Supports the LighNVM command set if indicated in vs[1].
 	 */
 	NVME_QUIRK_LIGHTNVM			= (1 << 6),
+
+	/*
+	 * Set MEDIUM priority on SQ creation
+	 */
+	NVME_QUIRK_MEDIUM_PRIO_SQ		= (1 << 7),
 };
 
 /*

drivers/nvme/host/pci.c

@@ -1093,9 +1093,18 @@ static int adapter_alloc_cq(struct nvme_dev *dev, u16 qid,
 static int adapter_alloc_sq(struct nvme_dev *dev, u16 qid,
 						struct nvme_queue *nvmeq)
 {
+	struct nvme_ctrl *ctrl = &dev->ctrl;
 	struct nvme_command c;
 	int flags = NVME_QUEUE_PHYS_CONTIG;
 
+	/*
+	 * Some drives have a bug that auto-enables WRRU if MEDIUM isn't
+	 * set. Since URGENT priority is zeroes, it makes all queues
+	 * URGENT.
+	 */
+	if (ctrl->quirks & NVME_QUIRK_MEDIUM_PRIO_SQ)
+		flags |= NVME_SQ_PRIO_MEDIUM;
+
 	/*
 	 * Note: we (ab)use the fact that the prp fields survive if no data
 	 * is attached to the request.
@@ -2701,7 +2710,8 @@ static const struct pci_device_id nvme_id_table[] = {
 		.driver_data = NVME_QUIRK_STRIPE_SIZE |
 				NVME_QUIRK_DEALLOCATE_ZEROES, },
 	{ PCI_VDEVICE(INTEL, 0xf1a5),	/* Intel 600P/P3100 */
-		.driver_data = NVME_QUIRK_NO_DEEPEST_PS },
+		.driver_data = NVME_QUIRK_NO_DEEPEST_PS |
+				NVME_QUIRK_MEDIUM_PRIO_SQ },
 	{ PCI_VDEVICE(INTEL, 0x5845),	/* Qemu emulated controller */
 		.driver_data = NVME_QUIRK_IDENTIFY_CNS, },
 	{ PCI_DEVICE(0x1c58, 0x0003),	/* HGST adapter */