NVMe: Set block queue max sectors

Set the max hw sectors in a namespace's request queue if the nvme device
has a max data transfer size.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

2 files changed, 8 insertions, 0 deletions

diff --git a/drivers/block/nvme.c b/drivers/block/nvme.c
index 7bcd88205a41..11951fa11a90 100644
--- a/drivers/block/nvme.c
+++ b/drivers/block/nvme.c
@@ -78,6 +78,7 @@ struct nvme_dev {
         char serial[20];
         char model[40];
         char firmware_rev[8];
+        u32 max_hw_sectors;
 };
 
 /*
@@ -1344,6 +1345,8 @@ static struct nvme_ns *nvme_alloc_ns(struct nvme_dev *dev, int nsid,
         lbaf = id->flbas & 0xf;
         ns->lba_shift = id->lbaf[lbaf].ds;
         blk_queue_logical_block_size(ns->queue, 1 << ns->lba_shift);
+        if (dev->max_hw_sectors)
+                blk_queue_max_hw_sectors(ns->queue, dev->max_hw_sectors);
 
         disk->major = nvme_major;
         disk->minors = NVME_MINORS;
@@ -1485,6 +1488,10 @@ static int __devinit nvme_dev_add(struct nvme_dev *dev)
         memcpy(dev->serial, ctrl->sn, sizeof(ctrl->sn));
         memcpy(dev->model, ctrl->mn, sizeof(ctrl->mn));
         memcpy(dev->firmware_rev, ctrl->fr, sizeof(ctrl->fr));
+        if (ctrl->mdts) {
+                int shift = NVME_CAP_MPSMIN(readq(&dev->bar->cap)) + 12;
+                dev->max_hw_sectors = 1 << (ctrl->mdts + shift - 9);
+        }
 
         id_ns = mem;
         for (i = 1; i <= nn; i++) {
diff --git a/include/linux/nvme.h b/include/linux/nvme.h
index 9490a00529f4..8c71d2004c6d 100644
--- a/include/linux/nvme.h
+++ b/include/linux/nvme.h
@@ -37,6 +37,7 @@ struct nvme_bar {
 
 #define NVME_CAP_TIMEOUT(cap)   (((cap) >> 24) & 0xff)
 #define NVME_CAP_STRIDE(cap)    (((cap) >> 32) & 0xf)
+#define NVME_CAP_MPSMIN(cap)    (((cap) >> 48) & 0xf)
 
 enum {
         NVME_CC_ENABLE          = 1 << 0,