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USB: Increase usbfs transfer limit 

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@fastmail.fm>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Mateusz Berezecki 2016-12-21 09:19:14 -08:00 committed by Greg Kroah-Hartman
parent 444d930998
commit 1129d270cb
1 changed files with 16 additions and 27 deletions
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43
drivers/usb/core/devio.c
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@ -134,42 +134,35 @@ enum snoop_when {
#define USB_DEVICE_DEV MKDEV(USB_DEVICE_MAJOR, 0) #define USB_DEVICE_DEV MKDEV(USB_DEVICE_MAJOR, 0)
/* Limit on the total amount of memory we can allocate for transfers */ /* 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_param(usbfs_memory_mb, uint, 0644);
MODULE_PARM_DESC(usbfs_memory_mb, MODULE_PARM_DESC(usbfs_memory_mb,
"maximum MB allowed for usbfs buffers (0 = no limit)"); "maximum MB allowed for usbfs buffers (0 = no limit)");
/* Hard limit, necessary to avoid arithmetic overflow */ static atomic64_t usbfs_memory_usage; /* Total memory currently allocated */
#define USBFS_XFER_MAX (UINT_MAX / 2 - 1000000)
static atomic_t usbfs_memory_usage; /* Total memory currently allocated */
/* Check whether it's okay to allocate more memory for a transfer */ /* 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); lim = ACCESS_ONCE(usbfs_memory_mb);
if (lim == 0 || lim > (USBFS_XFER_MAX >> 20)) lim <<= 20;
lim = USBFS_XFER_MAX;
else
lim <<= 20;
atomic_add(amount, &usbfs_memory_usage); atomic64_add(amount, &usbfs_memory_usage);
if (atomic_read(&usbfs_memory_usage) <= lim)
return 0; if (lim > 0 && atomic64_read(&usbfs_memory_usage) > lim) {
atomic_sub(amount, &usbfs_memory_usage); atomic64_sub(amount, &usbfs_memory_usage);
return -ENOMEM; return -ENOMEM;
}
return 0;
} }
/* Memory for a transfer is being deallocated */ /* 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) 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))) if (!usb_maxpacket(dev, pipe, !(bulk.ep & USB_DIR_IN)))
return -EINVAL; return -EINVAL;
len1 = bulk.len; len1 = bulk.len;
if (len1 >= USBFS_XFER_MAX) if (len1 >= (INT_MAX - sizeof(struct urb)))
return -EINVAL; return -EINVAL;
ret = usbfs_increase_memory_usage(len1 + sizeof(struct urb)); ret = usbfs_increase_memory_usage(len1 + sizeof(struct urb));
if (ret) if (ret)
@ -1584,10 +1577,6 @@ static int proc_do_submiturb(struct usb_dev_state *ps, struct usbdevfs_urb *uurb
return -EINVAL; return -EINVAL;
} }
if (uurb->buffer_length >= USBFS_XFER_MAX) {
ret = -EINVAL;
goto error;
}
if (uurb->buffer_length > 0 && if (uurb->buffer_length > 0 &&
!access_ok(is_in ? VERIFY_WRITE : VERIFY_READ, !access_ok(is_in ? VERIFY_WRITE : VERIFY_READ,
uurb->buffer, uurb->buffer_length)) { uurb->buffer, uurb->buffer_length)) {