Commit 02a4f8df9ca7a5cf3544edf40678f81e81274499
2013-10-14T11:44:37
Convert the usb callback function to using cgsem_t timed waits to avoid race conditions with conditionals/mutexes.
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diff --git a/usbutils.c b/usbutils.c
index f9cb228..cd7152d 100644
--- a/usbutils.c
+++ b/usbutils.c
@@ -2194,15 +2194,13 @@ static char *find_end(unsigned char *buf, unsigned char *ptr, int ptrlen, int to
#define USB_RETRY_MAX 5
struct usb_transfer {
- pthread_mutex_t mutex;
- pthread_cond_t cond;
+ cgsem_t cgsem;
struct libusb_transfer *transfer;
};
static void init_usb_transfer(struct usb_transfer *ut)
{
- mutex_init(&ut->mutex);
- pthread_cond_init(&ut->cond, NULL);
+ cgsem_init(&ut->cgsem);
ut->transfer = libusb_alloc_transfer(0);
if (unlikely(!ut->transfer))
quit(1, "Failed to libusb_alloc_transfer");
@@ -2213,7 +2211,7 @@ static void LIBUSB_CALL transfer_callback(struct libusb_transfer *transfer)
{
struct usb_transfer *ut = transfer->user_data;
- pthread_cond_signal(&ut->cond);
+ cgsem_post(&ut->cgsem);
}
/* Wait for callback function to tell us it has finished the USB transfer, but
@@ -2221,21 +2219,15 @@ static void LIBUSB_CALL transfer_callback(struct libusb_transfer *transfer)
static int callback_wait(struct usb_transfer *ut, int *transferred, unsigned int timeout)
{
struct libusb_transfer *transfer= ut->transfer;
- struct timespec ts_now, ts_end;
- struct timeval tv_now;
int ret;
- cgtime(&tv_now);
- ms_to_timespec(&ts_end, timeout);
- timeval_to_spec(&ts_now, &tv_now);
- timeraddspec(&ts_end, &ts_now);
- ret = pthread_cond_timedwait(&ut->cond, &ut->mutex, &ts_end);
- if (ret) {
+ ret = cgsem_mswait(&ut->cgsem, timeout);
+ if (ret == ETIMEDOUT) {
/* We are emulating a timeout ourself here */
libusb_cancel_transfer(transfer);
/* Now wait for the callback function to be invoked. */
- pthread_cond_wait(&ut->cond, &ut->mutex);
+ cgsem_wait(&ut->cgsem);
}
ret = transfer->status;
if (ret == LIBUSB_TRANSFER_CANCELLED)
@@ -2281,7 +2273,6 @@ usb_bulk_transfer(struct libusb_device_handle *dev_handle, int intinfo,
USBDEBUG("USB debug: @usb_bulk_transfer(%s (nodev=%s),intinfo=%d,epinfo=%d,data=%p,length=%d,timeout=%u,mode=%d,cmd=%s,seq=%d) endpoint=%d", cgpu->drv->name, bool_str(cgpu->usbinfo.nodev), intinfo, epinfo, data, length, timeout, mode, usb_cmdname(cmd), seq, (int)endpoint);
init_usb_transfer(&ut);
- mutex_lock(&ut.mutex);
/* We give the transfer no timeout since we manage timeouts ourself */
libusb_fill_bulk_transfer(ut.transfer, dev_handle, endpoint, buf, length,
transfer_callback, &ut, 0);
@@ -2714,7 +2705,6 @@ static int usb_control_transfer(libusb_device_handle *dev_handle, uint8_t bmRequ
int err, transferred;
init_usb_transfer(&ut);
- mutex_lock(&ut.mutex);
libusb_fill_control_setup(buf, bmRequestType, bRequest, wValue,
wIndex, wLength);
libusb_fill_control_transfer(ut.transfer, dev_handle, buf, transfer_callback,