Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Tom Yan <tom.ty89@gmail.com>
To:     hdegoede@redhat.com, hch@lst.de, gregkh@linuxfoundation.org,
        linux-usb@vger.kernel.org
Cc:     mathias.nyman@intel.com, linux-kernel@vger.kernel.org,
        linux-pci@vger.kernel.org, baolu.lu@linux.intel.com,
        Tom Yan <tom.ty89@gmail.com>
Subject: [PATCH 2/2] usb-storage: revert from scsi_add_host_with_dma() to scsi_add_host()
Date:   Sat, 28 Nov 2020 23:48:49 +0800
Message-Id: <20201128154849.3193-2-tom.ty89@gmail.com>
In-Reply-To: <20201128154849.3193-1-tom.ty89@gmail.com>
References: <09992cec-65e4-2757-aae6-8fb02a42f961@redhat.com>
 <20201128154849.3193-1-tom.ty89@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

While the change only seemed to have caused issue on uas drives, we
probably want to avoid it in the usb-storage driver as well, until
we are sure it is the right thing to do.

Signed-off-by: Tom Yan <tom.ty89@gmail.com>
---
 drivers/usb/storage/scsiglue.c | 40 +++++++++++++++++-----------------
 drivers/usb/storage/usb.c      |  3 +--
 2 files changed, 21 insertions(+), 22 deletions(-)

diff --git a/drivers/usb/storage/scsiglue.c b/drivers/usb/storage/scsiglue.c
index 560efd1479ba..6539bae1c188 100644
--- a/drivers/usb/storage/scsiglue.c
+++ b/drivers/usb/storage/scsiglue.c
@@ -92,7 +92,7 @@ static int slave_alloc (struct scsi_device *sdev)
 static int slave_configure(struct scsi_device *sdev)
 {
 	struct us_data *us = host_to_us(sdev->host);
-	struct device *dev = sdev->host->dma_dev;
+	struct device *dev = us->pusb_dev->bus->sysdev;
 
 	/*
 	 * Many devices have trouble transferring more than 32KB at a time,
@@ -120,6 +120,25 @@ static int slave_configure(struct scsi_device *sdev)
 		 * better throughput on most devices.
 		 */
 		blk_queue_max_hw_sectors(sdev->request_queue, 2048);
+	} else {
+		/*
+		 * Limit the total size of a transfer to 120 KB.
+		 *
+		 * Some devices are known to choke with anything larger. It seems like
+		 * the problem stems from the fact that original IDE controllers had
+		 * only an 8-bit register to hold the number of sectors in one transfer
+		 * and even those couldn't handle a full 256 sectors.
+		 *
+		 * Because we want to make sure we interoperate with as many devices as
+		 * possible, we will maintain a 240 sector transfer size limit for USB
+		 * Mass Storage devices.
+		 *
+		 * Tests show that other operating have similar limits with Microsoft
+		 * Windows 7 limiting transfers to 128 sectors for both USB2 and USB3
+		 * and Apple Mac OS X 10.11 limiting transfers to 256 sectors for USB2
+		 * and 2048 for USB3 devices.
+		 */
+		blk_queue_max_hw_sectors(sdev->request_queue, 240);
 	}
 
 	/*
@@ -627,25 +646,6 @@ static const struct scsi_host_template usb_stor_host_template = {
 	.sg_tablesize =			SG_MAX_SEGMENTS,
 
 
-	/*
-	 * Limit the total size of a transfer to 120 KB.
-	 *
-	 * Some devices are known to choke with anything larger. It seems like
-	 * the problem stems from the fact that original IDE controllers had
-	 * only an 8-bit register to hold the number of sectors in one transfer
-	 * and even those couldn't handle a full 256 sectors.
-	 *
-	 * Because we want to make sure we interoperate with as many devices as
-	 * possible, we will maintain a 240 sector transfer size limit for USB
-	 * Mass Storage devices.
-	 *
-	 * Tests show that other operating have similar limits with Microsoft
-	 * Windows 7 limiting transfers to 128 sectors for both USB2 and USB3
-	 * and Apple Mac OS X 10.11 limiting transfers to 256 sectors for USB2
-	 * and 2048 for USB3 devices.
-	 */
-	.max_sectors =                  240,
-
 	/* emulated HBA */
 	.emulated =			1,
 
diff --git a/drivers/usb/storage/usb.c b/drivers/usb/storage/usb.c
index c2ef367cf257..f177da4ff1bc 100644
--- a/drivers/usb/storage/usb.c
+++ b/drivers/usb/storage/usb.c
@@ -1050,8 +1050,7 @@ int usb_stor_probe2(struct us_data *us)
 	usb_autopm_get_interface_no_resume(us->pusb_intf);
 	snprintf(us->scsi_name, sizeof(us->scsi_name), "usb-storage %s",
 					dev_name(dev));
-	result = scsi_add_host_with_dma(us_to_host(us), dev,
-					us->pusb_dev->bus->sysdev);
+	result = scsi_add_host(us_to_host(us), dev);
 	if (result) {
 		dev_warn(dev,
 				"Unable to add the scsi host\n");
-- 
2.29.2