> Il giorno 15 dic 2016, alle ore 06:51, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> ha scritto:
>
> Hmmm, this is the third patch labelled v2 that you have mailed. In the
> future, be more careful about your version numbering.
Ok. Maybe I misunderstood versioning of patches. I thought of versions numbering the concept/approach rather than the actual revision of the patch. Should they all have been sent with an incremented number ?
>
>> On Wed, 14 Dec 2016, Mateusz Berezecki wrote:
>>
>> Promote a variable keeping track of USB transfer memory usage to a
>> wider data type and allow for higher bandwidth transfers from a large
>> number of USB devices connected to a single host.
>>
>> Signed-off-by: Mateusz Berezecki <mateuszb@xxxxxxxxxxx>
>> ---
>> drivers/usb/core/devio.c | 43 ++++++++++++++++---------------------------
>> 1 file changed, 16 insertions(+), 27 deletions(-)
>>
>> diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
>> index 4016dae..52747b6 100644
>> --- a/drivers/usb/core/devio.c
>> +++ b/drivers/usb/core/devio.c
>> @@ -134,42 +134,35 @@ enum snoop_when {
>> #define USB_DEVICE_DEV MKDEV(USB_DEVICE_MAJOR, 0)
>>
>> /* Limit on the total amount of memory we can allocate for transfers */
>> -static unsigned usbfs_memory_mb = 16;
>> +static u32 usbfs_memory_mb = 16;
>> module_param(usbfs_memory_mb, uint, 0644);
>> MODULE_PARM_DESC(usbfs_memory_mb,
>> "maximum MB allowed for usbfs buffers (0 = no limit)");
>>
>> -/* Hard limit, necessary to avoid arithmetic overflow */
>> -#define USBFS_XFER_MAX (UINT_MAX / 2 - 1000000)
>> -
>> -static atomic_t usbfs_memory_usage; /* Total memory currently allocated */
>> +static atomic64_t usbfs_memory_usage; /* Total memory currently allocated */
>>
>> /* Check whether it's okay to allocate more memory for a transfer */
>> -static int usbfs_increase_memory_usage(unsigned amount)
>> +static int usbfs_increase_memory_usage(u64 amount)
>> {
>> - unsigned lim;
>> + u64 lim;
>>
>> - /*
>> - * Convert usbfs_memory_mb to bytes, avoiding overflows.
>> - * 0 means use the hard limit (effectively unlimited).
>> - */
>> lim = ACCESS_ONCE(usbfs_memory_mb);
>> - if (lim == 0 || lim > (USBFS_XFER_MAX >> 20))
>> - lim = USBFS_XFER_MAX;
>> - else
>> - lim <<= 20;
>> + lim <<= 20;
>>
>> - atomic_add(amount, &usbfs_memory_usage);
>> - if (atomic_read(&usbfs_memory_usage) <= lim)
>> - return 0;
>> - atomic_sub(amount, &usbfs_memory_usage);
>> - return -ENOMEM;
>> + atomic64_add(amount, &usbfs_memory_usage);
>> +
>> + if (lim > 0 && atomic64_read(&usbfs_memory_usage) > lim) {
>> + atomic64_sub(amount, &usbfs_memory_usage);
>> + return -ENOMEM;
>> + }
>> +
>> + return 0;
>> }
>>
>> /* Memory for a transfer is being deallocated */
>> -static void usbfs_decrease_memory_usage(unsigned amount)
>> +static void usbfs_decrease_memory_usage(u64 amount)
>> {
>> - atomic_sub(amount, &usbfs_memory_usage);
>> + atomic64_sub(amount, &usbfs_memory_usage);
>> }
>>
>> static int connected(struct usb_dev_state *ps)
>> @@ -1191,7 +1184,7 @@ static int proc_bulk(struct usb_dev_state *ps, void __user *arg)
>> if (!usb_maxpacket(dev, pipe, !(bulk.ep & USB_DIR_IN)))
>> return -EINVAL;
>> len1 = bulk.len;
>> - if (len1 >= USBFS_XFER_MAX)
>> + if (len1 >= (INT_MAX - sizeof(struct urb)))
>> return -EINVAL;
>> ret = usbfs_increase_memory_usage(len1 + sizeof(struct urb));
>> if (ret)
>> @@ -1584,10 +1577,6 @@ static int proc_do_submiturb(struct usb_dev_state *ps, struct usbdevfs_urb *uurb
>> return -EINVAL;
>> }
>>
>> - if (uurb->buffer_length >= USBFS_XFER_MAX) {
>> - ret = -EINVAL;
>> - goto error;
>> - }
>> if (uurb->buffer_length > 0 &&
>> !access_ok(is_in ? VERIFY_WRITE : VERIFY_READ,
>> uurb->buffer, uurb->buffer_length)) {
>>
>
> This all looks good.
>
> Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Cool. Thanks for help and feedback!
Mateusz
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