Add a synchronize helper function for the virt-dma library. The function makes sure that any scheduled descriptor complete callbacks have finished running before the function returns.
This needs to be called by drivers using virt-dma in their device_synchronize() callback. Depending on the driver additional operations might be necessary in addition to calling vchan_synchronize() to ensure proper synchronization.
Signed-off-by: Lars-Peter Clausen lars@metafoo.de --- drivers/dma/virt-dma.h | 13 +++++++++++++ 1 file changed, 13 insertions(+)
diff --git a/drivers/dma/virt-dma.h b/drivers/dma/virt-dma.h index 181b9526..e93de76 100644 --- a/drivers/dma/virt-dma.h +++ b/drivers/dma/virt-dma.h @@ -151,4 +151,17 @@ static inline void vchan_free_chan_resources(struct virt_dma_chan *vc) vchan_dma_desc_free_list(vc, &head); }
+/** + * vchan_synchronize() - synchronize callback execution to the current context + * @vc: virtual channel to synchronize + * + * Makes sure that all scheduled or active callbacks have finished running. For + * proper operation the caller has to ensure that no new callbacks are scheduled + * after the invocation of this function started. + */ +static inline void vchan_synchronize(struct virt_dma_chan *vc) +{ + tasklet_kill(&vc->task); +} + #endif