Hi,
Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> writes:
> On Wed, 4 Nov 2015, Felipe Balbi wrote:
>
>> USB3 devices, because they are much newer, have much
>> less chance of having issues with larger transfers.
>>
>> We still keep a limit because anything above 2048
>> sectors really rendered negligible speed
>> improvements, so we will simply ignore
>> that. Transferring 1MiB should already give us
>> pretty good performance.
>>
>> Signed-off-by: Felipe Balbi <balbi@xxxxxx>
>> ---
>> drivers/usb/storage/scsiglue.c | 16 +++++++++++-----
>> drivers/usb/storage/usb.c | 4 ++++
>> include/linux/usb_usual.h | 2 ++
>> 3 files changed, 17 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/usb/storage/scsiglue.c b/drivers/usb/storage/scsiglue.c
>> index 00aadf3a3857..bda2b3c9ae42 100644
>> --- a/drivers/usb/storage/scsiglue.c
>> +++ b/drivers/usb/storage/scsiglue.c
>> @@ -115,13 +115,19 @@ static int slave_configure(struct scsi_device *sdev)
>> {
>> struct us_data *us = host_to_us(sdev->host);
>>
>> - /* Many devices have trouble transferring more than 32KB at a time,
>> - * while others have trouble with more than 64K. At this time we
>> - * are limiting both to 32K (64 sectores).
>> - */
>> - if (us->fflags & (US_FL_MAX_SECTORS_64 | US_FL_MAX_SECTORS_MIN)) {
>> + if (us->fflags & US_FL_USB3) {
>
> ...
>
>> --- a/include/linux/usb_usual.h
>> +++ b/include/linux/usb_usual.h
>> @@ -79,6 +79,8 @@
>> /* Cannot handle MI_REPORT_SUPPORTED_OPERATION_CODES */ \
>> US_FLAG(MAX_SECTORS_240, 0x08000000) \
>> /* Sets max_sectors to 240 */ \
>> + US_FLAG(USB3, 0x10000000) \
>> + /* This is a USB3 Storage Device */ \
>
> This doesn't need to be stored as one of the usb-storage flags. And
> since we are close to running out of flag bits (on 32-bit
> architectures), it would be better not to use one of them for this.
>
> The test above can be rewritten as:
>
> if (us->pusb_dev->speed >= USB_SPEED_SUPER)
>
> Since it gets used in only this one place and it's not on a hot path,
> this is how it should be done
cool, this is much better. Fixed. I'll wait another day or two before
resending. It's the beginning of the merge window anyway.
--
balbi
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