From: Sathyavathi M <sathya.m@samsung.com>
Date: Thu, 5 Nov 2015 19:52:28 +0000 (-0700)
Subject: NVMe: Increase the max transfer size when mdts is 0
X-Git-Tag: v4.4-rc1~24^2~8
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=b12363d0a5da00c422641f3d926fffb713192ea3;p=linux.git

NVMe: Increase the max transfer size when mdts is 0

This patch address the issue when IO with 128KB from FIO is split into
two parts, 124KB and 4KB, due to max transfer size(127KB). This degrades
the device performance.

Signed-off-by: Sathyavathi M <sathya.m@samsung.com>
Acked-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
---

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 3dfc28875cc3..cb89789df40c 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -2622,6 +2622,8 @@ static int nvme_dev_add(struct nvme_dev *dev)
 	memcpy(dev->firmware_rev, ctrl->fr, sizeof(ctrl->fr));
 	if (ctrl->mdts)
 		dev->max_hw_sectors = 1 << (ctrl->mdts + shift - 9);
+	else
+		dev->max_hw_sectors = UINT_MAX;
 	if ((pdev->vendor == PCI_VENDOR_ID_INTEL) &&
 			(pdev->device == 0x0953) && ctrl->vs[3]) {
 		unsigned int max_hw_sectors;