return 0;
}
-/* add a transfer to the (timeout-sorted) active transfers list.
- * Callers of this function must hold the flying_transfers_lock.
- * This function *always* adds the transfer to the flying_transfers list,
- * it will return non 0 if it fails to update the timer, but even then the
- * transfer is added to the flying_transfers list. */
-static int add_to_flying_list(struct usbi_transfer *transfer)
-{
- struct usbi_transfer *cur;
- struct timeval *timeout = &transfer->timeout;
- struct libusb_context *ctx = ITRANSFER_CTX(transfer);
- int r = 0;
- int first = 1;
-
- /* if we have no other flying transfers, start the list with this one */
- if (list_empty(&ctx->flying_transfers)) {
- list_add(&transfer->list, &ctx->flying_transfers);
- goto out;
- }
-
- /* if we have infinite timeout, append to end of list */
- if (!timerisset(timeout)) {
- list_add_tail(&transfer->list, &ctx->flying_transfers);
- /* first is irrelevant in this case */
- goto out;
- }
-
- /* otherwise, find appropriate place in list */
- list_for_each_entry(cur, &ctx->flying_transfers, list, struct usbi_transfer) {
- /* find first timeout that occurs after the transfer in question */
- struct timeval *cur_tv = &cur->timeout;
-
- if (!timerisset(cur_tv) || (cur_tv->tv_sec > timeout->tv_sec) ||
- (cur_tv->tv_sec == timeout->tv_sec &&
- cur_tv->tv_usec > timeout->tv_usec)) {
- list_add_tail(&transfer->list, &cur->list);
- goto out;
- }
- first = 0;
- }
- /* first is 0 at this stage (list not empty) */
-
- /* otherwise we need to be inserted at the end */
- list_add_tail(&transfer->list, &ctx->flying_transfers);
-out:
-#ifdef USBI_TIMERFD_AVAILABLE
- if (first && usbi_using_timerfd(ctx) && timerisset(timeout)) {
- /* if this transfer has the lowest timeout of all active transfers,
- * rearm the timerfd with this transfer's timeout */
- const struct itimerspec it = { {0, 0},
- { timeout->tv_sec, timeout->tv_usec * 1000 } };
- usbi_dbg("arm timerfd for timeout in %dms (first in line)",
- USBI_TRANSFER_TO_LIBUSB_TRANSFER(transfer)->timeout);
- r = timerfd_settime(ctx->timerfd, TFD_TIMER_ABSTIME, &it, NULL);
- if (r < 0) {
- usbi_warn(ctx, "failed to arm first timerfd (errno %d)", errno);
- r = LIBUSB_ERROR_OTHER;
- }
- }
-#else
- UNUSED(first);
-#endif
-
- return r;
-}
-
/** \ingroup asyncio
* Allocate a libusb transfer with a specified number of isochronous packet
* descriptors. The returned transfer is pre-initialized for you. When the new
itransfer->num_iso_packets = iso_packets;
usbi_mutex_init(&itransfer->lock, NULL);
+ usbi_mutex_init(&itransfer->flags_lock, NULL);
transfer = USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
usbi_dbg("transfer %p", transfer);
return transfer;
itransfer = LIBUSB_TRANSFER_TO_USBI_TRANSFER(transfer);
usbi_mutex_destroy(&itransfer->lock);
+ usbi_mutex_destroy(&itransfer->flags_lock);
free(itransfer);
}
}
#endif
+/* add a transfer to the (timeout-sorted) active transfers list.
+ * This function will return non 0 if fails to update the timer,
+ * in which case the transfer is *not* on the flying_transfers list. */
+static int add_to_flying_list(struct usbi_transfer *transfer)
+{
+ struct usbi_transfer *cur;
+ struct timeval *timeout = &transfer->timeout;
+ struct libusb_context *ctx = ITRANSFER_CTX(transfer);
+ int r = 0;
+ int first = 1;
+
+ usbi_mutex_lock(&ctx->flying_transfers_lock);
+
+ /* if we have no other flying transfers, start the list with this one */
+ if (list_empty(&ctx->flying_transfers)) {
+ list_add(&transfer->list, &ctx->flying_transfers);
+ goto out;
+ }
+
+ /* if we have infinite timeout, append to end of list */
+ if (!timerisset(timeout)) {
+ list_add_tail(&transfer->list, &ctx->flying_transfers);
+ /* first is irrelevant in this case */
+ goto out;
+ }
+
+ /* otherwise, find appropriate place in list */
+ list_for_each_entry(cur, &ctx->flying_transfers, list, struct usbi_transfer) {
+ /* find first timeout that occurs after the transfer in question */
+ struct timeval *cur_tv = &cur->timeout;
+
+ if (!timerisset(cur_tv) || (cur_tv->tv_sec > timeout->tv_sec) ||
+ (cur_tv->tv_sec == timeout->tv_sec &&
+ cur_tv->tv_usec > timeout->tv_usec)) {
+ list_add_tail(&transfer->list, &cur->list);
+ goto out;
+ }
+ first = 0;
+ }
+ /* first is 0 at this stage (list not empty) */
+
+ /* otherwise we need to be inserted at the end */
+ list_add_tail(&transfer->list, &ctx->flying_transfers);
+out:
+#ifdef USBI_TIMERFD_AVAILABLE
+ if (first && usbi_using_timerfd(ctx) && timerisset(timeout)) {
+ /* if this transfer has the lowest timeout of all active transfers,
+ * rearm the timerfd with this transfer's timeout */
+ const struct itimerspec it = { {0, 0},
+ { timeout->tv_sec, timeout->tv_usec * 1000 } };
+ usbi_dbg("arm timerfd for timeout in %dms (first in line)",
+ USBI_TRANSFER_TO_LIBUSB_TRANSFER(transfer)->timeout);
+ r = timerfd_settime(ctx->timerfd, TFD_TIMER_ABSTIME, &it, NULL);
+ if (r < 0) {
+ usbi_warn(ctx, "failed to arm first timerfd (errno %d)", errno);
+ r = LIBUSB_ERROR_OTHER;
+ }
+ }
+#else
+ UNUSED(first);
+#endif
+
+ if (r)
+ list_del(&transfer->list);
+
+ usbi_mutex_unlock(&ctx->flying_transfers_lock);
+ return r;
+}
+
+/* remove a transfer from the active transfers list.
+ * This function will *always* remove the transfer from the
+ * flying_transfers list. It will return non 0 if it fails to
+ * update the timer for the next timeout. */
+static int remove_from_flying_list(struct usbi_transfer *transfer)
+{
+ struct libusb_context *ctx = ITRANSFER_CTX(transfer);
+ int r = 0;
+
+ /* FIXME: could be more intelligent with the timerfd here. we don't need
+ * to disarm the timerfd if there was no timer running, and we only need
+ * to rearm the timerfd if the transfer that expired was the one with
+ * the shortest timeout. */
+
+ usbi_mutex_lock(&ctx->flying_transfers_lock);
+ list_del(&transfer->list);
+ if (usbi_using_timerfd(ctx))
+ r = arm_timerfd_for_next_timeout(ctx);
+ usbi_mutex_unlock(&ctx->flying_transfers_lock);
+
+ return r;
+}
+
/** \ingroup asyncio
* Submit a transfer. This function will fire off the USB transfer and then
* return immediately.
*/
int API_EXPORTED libusb_submit_transfer(struct libusb_transfer *transfer)
{
- struct libusb_context *ctx = TRANSFER_CTX(transfer);
struct usbi_transfer *itransfer =
LIBUSB_TRANSFER_TO_USBI_TRANSFER(transfer);
+ int remove = 0;
int r;
usbi_dbg("transfer %p", transfer);
- usbi_mutex_lock(&ctx->flying_transfers_lock);
usbi_mutex_lock(&itransfer->lock);
+ usbi_mutex_lock(&itransfer->flags_lock);
if (itransfer->flags & USBI_TRANSFER_IN_FLIGHT) {
r = LIBUSB_ERROR_BUSY;
goto out;
r = LIBUSB_ERROR_OTHER;
goto out;
}
+ itransfer->flags |= USBI_TRANSFER_SUBMITTING;
+ usbi_mutex_unlock(&itransfer->flags_lock);
r = add_to_flying_list(itransfer);
- if (r == LIBUSB_SUCCESS) {
- r = usbi_backend->submit_transfer(itransfer);
+ if (r) {
+ usbi_mutex_lock(&itransfer->flags_lock);
+ itransfer->flags = 0;
+ goto out;
}
- if (r != LIBUSB_SUCCESS) {
- list_del(&itransfer->list);
- arm_timerfd_for_next_timeout(ctx);
+
+ /* keep a reference to this device */
+ libusb_ref_device(transfer->dev_handle->dev);
+ r = usbi_backend->submit_transfer(itransfer);
+
+ usbi_mutex_lock(&itransfer->flags_lock);
+ itransfer->flags &= ~USBI_TRANSFER_SUBMITTING;
+ if (r == LIBUSB_SUCCESS) {
+ /* check for two possible special conditions:
+ * 1) device disconnect occurred immediately after submission
+ * 2) transfer completed before we got here to update the flags
+ */
+ if (itransfer->flags & USBI_TRANSFER_DEVICE_DISAPPEARED) {
+ usbi_backend->clear_transfer_priv(itransfer);
+ remove = 1;
+ r = LIBUSB_ERROR_NO_DEVICE;
+ }
+ else if (!(itransfer->flags & USBI_TRANSFER_COMPLETED)) {
+ itransfer->flags |= USBI_TRANSFER_IN_FLIGHT;
+ }
} else {
- itransfer->flags |= USBI_TRANSFER_IN_FLIGHT;
- /* keep a reference to this device */
- libusb_ref_device(transfer->dev_handle->dev);
+ remove = 1;
}
out:
+ usbi_mutex_unlock(&itransfer->flags_lock);
+ if (remove) {
+ libusb_unref_device(transfer->dev_handle->dev);
+ remove_from_flying_list(itransfer);
+ }
usbi_mutex_unlock(&itransfer->lock);
- usbi_mutex_unlock(&ctx->flying_transfers_lock);
return r;
}
usbi_dbg("transfer %p", transfer );
usbi_mutex_lock(&itransfer->lock);
+ usbi_mutex_lock(&itransfer->flags_lock);
if (!(itransfer->flags & USBI_TRANSFER_IN_FLIGHT)
|| (itransfer->flags & USBI_TRANSFER_CANCELLING)) {
r = LIBUSB_ERROR_NOT_FOUND;
itransfer->flags |= USBI_TRANSFER_CANCELLING;
out:
+ usbi_mutex_unlock(&itransfer->flags_lock);
usbi_mutex_unlock(&itransfer->lock);
return r;
}
{
struct libusb_transfer *transfer =
USBI_TRANSFER_TO_LIBUSB_TRANSFER(itransfer);
- struct libusb_context *ctx = TRANSFER_CTX(transfer);
struct libusb_device_handle *handle = transfer->dev_handle;
uint8_t flags;
- int r = 0;
-
- /* FIXME: could be more intelligent with the timerfd here. we don't need
- * to disarm the timerfd if there was no timer running, and we only need
- * to rearm the timerfd if the transfer that expired was the one with
- * the shortest timeout. */
+ int r;
- usbi_mutex_lock(&ctx->flying_transfers_lock);
- list_del(&itransfer->list);
- if (usbi_using_timerfd(ctx))
- r = arm_timerfd_for_next_timeout(ctx);
- usbi_mutex_unlock(&ctx->flying_transfers_lock);
- if (usbi_using_timerfd(ctx) && (r < 0))
+ r = remove_from_flying_list(itransfer);
+ if (r)
return r;
- usbi_mutex_lock(&itransfer->lock);
+ usbi_mutex_lock(&itransfer->flags_lock);
itransfer->flags &= ~USBI_TRANSFER_IN_FLIGHT;
- usbi_mutex_unlock(&itransfer->lock);
+ itransfer->flags |= USBI_TRANSFER_COMPLETED;
+ usbi_mutex_unlock(&itransfer->flags_lock);
if (status == LIBUSB_TRANSFER_COMPLETED
&& transfer->flags & LIBUSB_TRANSFER_SHORT_NOT_OK) {
/* terminate all pending transfers with the LIBUSB_TRANSFER_NO_DEVICE
* status code.
*
- * this is a bit tricky because:
- * 1. we can't do transfer completion while holding flying_transfers_lock
- * because the completion handler may try to re-submit the transfer
- * 2. the transfers list can change underneath us - if we were to build a
- * list of transfers to complete (while holding lock), the situation
- * might be different by the time we come to free them
- *
- * so we resort to a loop-based approach as below
- *
- * This is safe because transfers are only removed from the
- * flying_transfer list by usbi_handle_transfer_completion and
- * libusb_close, both of which hold the events_lock while doing so,
- * so usbi_handle_disconnect cannot be running at the same time.
- *
- * Note that libusb_submit_transfer also removes the transfer from
- * the flying_transfer list on submission failure, but it keeps the
- * flying_transfer list locked between addition and removal, so
- * usbi_handle_disconnect never sees such transfers.
+ * when we find a transfer for this device on the list, there are two
+ * possible scenarios:
+ * 1. the transfer is currently in-flight, in which case we terminate the
+ * transfer here
+ * 2. the transfer is not in-flight (or is but hasn't been marked as such),
+ * in which case we record that the device disappeared and this will be
+ * handled by libusb_submit_transfer()
*/
while (1) {
- usbi_mutex_lock(&HANDLE_CTX(handle)->flying_transfers_lock);
to_cancel = NULL;
+ usbi_mutex_lock(&HANDLE_CTX(handle)->flying_transfers_lock);
list_for_each_entry(cur, &HANDLE_CTX(handle)->flying_transfers, list, struct usbi_transfer)
if (USBI_TRANSFER_TO_LIBUSB_TRANSFER(cur)->dev_handle == handle) {
- to_cancel = cur;
- break;
+ usbi_mutex_lock(&cur->flags_lock);
+ if (cur->flags & USBI_TRANSFER_IN_FLIGHT)
+ to_cancel = cur;
+ else
+ cur->flags |= USBI_TRANSFER_DEVICE_DISAPPEARED;
+ usbi_mutex_unlock(&cur->flags_lock);
+
+ if (to_cancel)
+ break;
}
usbi_mutex_unlock(&HANDLE_CTX(handle)->flying_transfers_lock);
usbi_dbg("cancelling transfer %p from disconnect",
USBI_TRANSFER_TO_LIBUSB_TRANSFER(to_cancel));
+ usbi_mutex_lock(&to_cancel->lock);
usbi_backend->clear_transfer_priv(to_cancel);
+ usbi_mutex_unlock(&to_cancel->lock);
usbi_handle_transfer_completion(to_cancel, LIBUSB_TRANSFER_NO_DEVICE);
}
projects / platform / upstream / libusb.git / commitdiff