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nvme/pci: Remove nvme_setup_prps BUG_ON

PATCH New Keith Busch 4 participants 4 messages Jul 12, 2017 – Jul 13, 2017 NVMe

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#0 lore raw

PATCH 1/1 nvme/pci: Remove nvme_setup_prps BUG_ON

This patch replaces the invalid nvme SGL kernel panic with a warning, and returns an appropriate error. The warning will occur only on the first occurance, and sgl details will be printed to help debug how the request was allowed to form.

Signed-off-by Keith Busch <keith.busch at intel.com>
---
 drivers/nvme/host/pci.c | 33 +++++++++++++++++++++++++--------
 1 file changed, 25 insertions(+), 8 deletions(-)
drivers/nvme/host/pci.c +25 -8
index c4343c4..d321597 100644
@@ -533,7 +533,7 @@ static void nvme_dif_complete(u32 p, u32 v, struct t10_pi_tuple *pi)
 }
 #endif
 
-static bool nvme_setup_prps(struct nvme_dev *dev, struct request *req)
+static blk_status_t nvme_setup_prps(struct nvme_dev *dev, struct request *req)
 {
 	struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
 	struct dma_pool *pool;
@@ -550,7 +550,7 @@ static bool nvme_setup_prps(struct nvme_dev *dev, struct request *req)
 
 	length -= (page_size - offset);
 	if (length <= 0)
-		return true;
+		return BLK_STS_OK;
 
 	dma_len -= (page_size - offset);
 	if (dma_len) {
@@ -563,7 +563,7 @@ static bool nvme_setup_prps(struct nvme_dev *dev, struct request *req)
 
 	if (length <= page_size) {
 		iod->first_dma = dma_addr;
-		return true;
+		return BLK_STS_OK;
 	}
 
 	nprps = DIV_ROUND_UP(length, page_size);
@@ -579,7 +579,7 @@ static bool nvme_setup_prps(struct nvme_dev *dev, struct request *req)
 	if (!prp_list) {
 		iod->first_dma = dma_addr;
 		iod->npages = -1;
-		return false;
+		return BLK_STS_RESOURCE;
 	}
 	list[0] = prp_list;
 	iod->first_dma = prp_dma;
@@ -589,7 +589,7 @@ static bool nvme_setup_prps(struct nvme_dev *dev, struct request *req)
 			__le64 *old_prp_list = prp_list;
 			prp_list = dma_pool_alloc(pool, GFP_ATOMIC, &prp_dma);
 			if (!prp_list)
-				return false;
+				return BLK_STS_RESOURCE;
 			list[iod->npages++] = prp_list;
 			prp_list[0] = old_prp_list[i - 1];
 			old_prp_list[i - 1] = cpu_to_le64(prp_dma);
@@ -603,13 +603,29 @@ static bool nvme_setup_prps(struct nvme_dev *dev, struct request *req)
 			break;
 		if (dma_len > 0)
 			continue;
-		BUG_ON(dma_len < 0);
+		if (unlikely(dma_len < 0))
+			goto bad_sgl;
 		sg = sg_next(sg);
 		dma_addr = sg_dma_address(sg);
 		dma_len = sg_dma_len(sg);
 	}
 
-	return true;
+	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));
+		}
+	}
+	return BLK_STS_IOERR;
+
 }
 
 static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req,
@@ -631,7 +647,8 @@ static blk_status_t nvme_map_data(struct nvme_dev *dev, struct request *req,
 				DMA_ATTR_NO_WARN))
 		goto out;
 
-	if (!nvme_setup_prps(dev, req))
+	ret = nvme_setup_prps(dev, req);
+	if (ret != BLK_STS_OK)
 		goto out_unmap;
 
 	ret = BLK_STS_IOERR;
Signature · 1 line
2.5.5
maintainer
#1 lore raw

PATCH 1/1 nvme/pci: Remove nvme_setup_prps BUG_ON

Quoted 4 lines

This patch replaces the invalid nvme SGL kernel panic with a warning, and returns an appropriate error. The warning will occur only on the first occurance, and sgl details will be printed to help debug how the request was allowed to form.

That's definitely needed! Looks great,

Reviewed-by Sagi Grimberg <sagi at grimberg.m>
#3 lore raw

PATCH 1/1 nvme/pci: Remove nvme_setup_prps BUG_ON

In reply to Keith Busch

Highly appreciated,
Reviewed-by: Johannes Thumshirn <jthumshirn at suse.de>

Signature · 6 lines
Johannes Thumshirn                                          Storage
jthumshirn at suse.de                                +49 911 74053 689
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 N?rnberg
GF: Felix Imend?rffer, Jane Smithard, Graham Norton
HRB 21284 (AG N?rnberg)
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