It's merely a moving of comment moving for/and a no-behavioral-change
adaptation for the reversion. Similar has been done in the equivalent
patch for the UAS driver (and the reason is stated there).
On Mon, 30 Nov 2020 at 17:50, Hans de Goede <hdegoede@xxxxxxxxxx> wrote:
>
> Hi,
>
> On 11/28/20 4:48 PM, Tom Yan wrote:
> > 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@xxxxxxxxx>
>
> This seems to do a whole lot more then just dropping back from
> scsi_add_host_with_dma() to scsi_add_host(). This has way more
> lines then the orginal commit.
>
> IMHO it would be best to just revert commit 0154012f8018bba4d9971d1007c12ffd48539ddb
> and then submit these changes as a separate patch (which would be
> 5.11 material then).
>
> That separate patch could then also have a proper commit message
> explaining the other changes you are making, which is also not
> unimportant.
>
> Regards,
>
> Hans
>
>
>
>
> > ---
> > 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");
> >
>
