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cdc-acm: reassemble fragmented notifications

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USB devices may have very limited endpoint packet sizes, so that
notifications can not be transferred within one single usb packet.
Reassembling of multiple packages may be necessary.

Signed-off-by: Tobias Herzog <t-herzog@gmx.de>
Acked-by: Oliver Neukum <oneukum@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Tobias Herzog 2017-03-30 22:15:11 +02:00 committed by Greg Kroah-Hartman
parent 1bb9914e17
commit ea2583529c
2 changed files with 88 additions and 31 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

116
drivers/usb/class/cdc-acm.c
View file

@ -36,6 +36,7 @@
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/log2.h>
#include <linux/tty.h>
#include <linux/serial.h>
#include <linux/tty_driver.h>
@ -283,39 +284,13 @@ static DEVICE_ATTR(iCountryCodeRelDate, S_IRUGO, show_country_rel_date, NULL);
* Interrupt handlers for various ACM device responses
*/
/* control interface reports status changes with "interrupt" transfers */
static void acm_ctrl_irq(struct urb *urb)
static void acm_process_notification(struct acm *acm, unsigned char *buf)
{
struct acm *acm = urb->context;
struct usb_cdc_notification *dr = urb->transfer_buffer;
unsigned char *data;
int newctrl;
int difference;
int retval;
int status = urb->status;
struct usb_cdc_notification *dr = (struct usb_cdc_notification *)buf;
unsigned char *data = buf + sizeof(struct usb_cdc_notification);
switch (status) {
case 0:
/* success */
break;
case -ECONNRESET:
case -ENOENT:
case -ESHUTDOWN:
/* this urb is terminated, clean up */
dev_dbg(&acm->control->dev,
"%s - urb shutting down with status: %d\n",
__func__, status);
return;
default:
dev_dbg(&acm->control->dev,
"%s - nonzero urb status received: %d\n",
__func__, status);
goto exit;
}
usb_mark_last_busy(acm->dev);
data = (unsigned char *)(dr + 1);
switch (dr->bNotificationType) {
case USB_CDC_NOTIFY_NETWORK_CONNECTION:
dev_dbg(&acm->control->dev,
@ -368,9 +343,83 @@ static void acm_ctrl_irq(struct urb *urb)
"%s - unknown notification %d received: index %d len %d\n",
__func__,
dr->bNotificationType, dr->wIndex, dr->wLength);
break;
}
}
/* control interface reports status changes with "interrupt" transfers */
static void acm_ctrl_irq(struct urb *urb)
{
struct acm *acm = urb->context;
struct usb_cdc_notification *dr = urb->transfer_buffer;
unsigned int current_size = urb->actual_length;
unsigned int expected_size, copy_size, alloc_size;
int retval;
int status = urb->status;
switch (status) {
case 0:
/* success */
break;
case -ECONNRESET:
case -ENOENT:
case -ESHUTDOWN:
/* this urb is terminated, clean up */
acm->nb_index = 0;
dev_dbg(&acm->control->dev,
"%s - urb shutting down with status: %d\n",
__func__, status);
return;
default:
dev_dbg(&acm->control->dev,
"%s - nonzero urb status received: %d\n",
__func__, status);
goto exit;
}
usb_mark_last_busy(acm->dev);
if (acm->nb_index)
dr = (struct usb_cdc_notification *)acm->notification_buffer;
/* size = notification-header + (optional) data */
expected_size = sizeof(struct usb_cdc_notification) +
le16_to_cpu(dr->wLength);
if (current_size < expected_size) {
/* notification is transmitted fragmented, reassemble */
if (acm->nb_size < expected_size) {
if (acm->nb_size) {
kfree(acm->notification_buffer);
acm->nb_size = 0;
}
alloc_size = roundup_pow_of_two(expected_size);
/*
* kmalloc ensures a valid notification_buffer after a
* use of kfree in case the previous allocation was too
* small. Final freeing is done on disconnect.
*/
acm->notification_buffer =
kmalloc(alloc_size, GFP_ATOMIC);
if (!acm->notification_buffer)
goto exit;
acm->nb_size = alloc_size;
}
copy_size = min(current_size,
expected_size - acm->nb_index);
memcpy(&acm->notification_buffer[acm->nb_index],
urb->transfer_buffer, copy_size);
acm->nb_index += copy_size;
current_size = acm->nb_index;
}
if (current_size >= expected_size) {
/* notification complete */
acm_process_notification(acm, (unsigned char *)dr);
acm->nb_index = 0;
}
exit:
retval = usb_submit_urb(urb, GFP_ATOMIC);
if (retval && retval != -EPERM)
@ -1483,6 +1532,9 @@ static int acm_probe(struct usb_interface *intf,
epctrl->bInterval ? epctrl->bInterval : 16);
acm->ctrlurb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
acm->ctrlurb->transfer_dma = acm->ctrl_dma;
acm->notification_buffer = NULL;
acm->nb_index = 0;
acm->nb_size = 0;
dev_info(&intf->dev, "ttyACM%d: USB ACM device\n", minor);
@ -1575,6 +1627,8 @@ static void acm_disconnect(struct usb_interface *intf)
usb_free_coherent(acm->dev, acm->ctrlsize, acm->ctrl_buffer, acm->ctrl_dma);
acm_read_buffers_free(acm);
kfree(acm->notification_buffer);
if (!acm->combined_interfaces)
usb_driver_release_interface(&acm_driver, intf == acm->control ?
acm->data : acm->control);

3
drivers/usb/class/cdc-acm.h
View file

@ -98,6 +98,9 @@ struct acm {
struct acm_wb *putbuffer; /* for acm_tty_put_char() */
int rx_buflimit;
spinlock_t read_lock;
u8 *notification_buffer; /* to reassemble fragmented notifications */
unsigned int nb_index;
unsigned int nb_size;
int write_used; /* number of non-empty write buffers */
int transmitting;
spinlock_t write_lock;