From: Keith Busch <keith.busch@intel.com>
Date: Fri, 15 Sep 2017 13:05:38 -0400
Subject: nvme-pci: Print invalid SGL only once
Patch-mainline: v4.14-rc3
Git-commit: d08774738446e77734777adcf5d1045237b4475a
References: FATE#323952, FATE#322506

The WARN_ONCE macro returns true if the condition is true, not if the
warn was raised, so we're printing the scatter list every time it's
invalid. This is excessive and makes debugging harder, so this patch
prints it just once.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Johannes Thumshirn <jthumshirn@suse.de>
---
 drivers/nvme/host/pci.c |   30 ++++++++++++++++++------------
 1 file changed, 18 insertions(+), 12 deletions(-)

--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -24,6 +24,7 @@
 #include <linux/mm.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
+#include <linux/once.h>
 #include <linux/pci.h>
 #include <linux/poison.h>
 #include <linux/t10-pi.h>
@@ -540,6 +541,20 @@ static void nvme_dif_complete(u32 p, u32
 }
 #endif
 
+static void nvme_print_sgl(struct scatterlist *sgl, int nents)
+{
+	int i;
+	struct scatterlist *sg;
+
+	for_each_sg(sgl, sg, nents, i) {
+		dma_addr_t phys = sg_phys(sg);
+		pr_warn("sg[%d] phys_addr:%pad offset:%d length:%d "
+			"dma_address:%pad dma_length:%d\n",
+			i, &phys, sg->offset, sg->length, &sg_dma_address(sg),
+			sg_dma_len(sg));
+	}
+}
+
 static blk_status_t nvme_setup_prps(struct nvme_dev *dev, struct request *req)
 {
 	struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
@@ -622,19 +637,10 @@ static blk_status_t nvme_setup_prps(stru
 	return BLK_STS_OK;
 
  bad_sgl:
-	if (WARN_ONCE(1, "Invalid SGL for payload:%d nents:%d\n",
-				blk_rq_payload_bytes(req), iod->nents)) {
-		for_each_sg(iod->sg, sg, iod->nents, i) {
-			dma_addr_t phys = sg_phys(sg);
-			pr_warn("sg[%d] phys_addr:%pad offset:%d length:%d "
-			       "dma_address:%pad dma_length:%d\n", i, &phys,
-					sg->offset, sg->length,
-					&sg_dma_address(sg),
-					sg_dma_len(sg));
-		}
-	}
+	WARN(DO_ONCE(nvme_print_sgl, iod->sg, iod->nents),
+			"Invalid SGL for payload:%d nents:%d\n",
+			blk_rq_payload_bytes(req), iod->nents);
 	return BLK_STS_IOERR;
-
 }
 
 static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req,