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 <[email protected]> --- drivers/usb/core/devio.c | 48 ++++++++++++++++++++++++------------------------ 1 file changed, 24 insertions(+), 24 deletions(-) diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c index 4016dae..99c8e27 100644 --- a/drivers/usb/core/devio.c +++ b/drivers/usb/core/devio.c @@ -134,42 +134,37 @@ 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) { + if (atomic64_read(&usbfs_memory_usage) <= lim) + return 0; + 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 +1186,7 @@ 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) @@ -1458,6 +1453,7 @@ static int proc_do_submiturb(struct usb_dev_state *ps, struct usbdevfs_urb *uurb int number_of_packets = 0; unsigned int stream_id = 0; void *buf; + u32 overhead; if (uurb->flags & ~(USBDEVFS_URB_ISO_ASAP | USBDEVFS_URB_SHORT_NOT_OK | @@ -1584,7 +1580,11 @@ static int proc_do_submiturb(struct usb_dev_state *ps, struct usbdevfs_urb *uurb return -EINVAL; } - if (uurb->buffer_length >= USBFS_XFER_MAX) { + /* check for overflow */ + overhead = u + sizeof(struct async) + sizeof(struct urb) + + num_sgs * sizeof(struct scatterlist); + + if (uurb->buffer_length + overhead < uurb->buffer_length) { ret = -EINVAL; goto error; } -- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
