dmaengine: rcar-dmac: Check the done lists in rcar_dmac_chan_get_residue()
This patch fixes an issue that a race condition happens between a client
driver and the rcar-dmac driver:
- The rcar_dmac_isr_transfer_end() is called.
- The done list appears, and desc.running is the next active list.
- rcar_dmac_chan_get_residue() is called by a client driver before
rcar_dmac_isr_channel_thread() is called.
- The rcar_dmac_chan_get_residue() will not find any descriptors.
- And, the following WARNING happens:
WARN(1, "No descriptor for cookie!");
The sh-sci driver with HSCIF (921,600bps) on R-Car H3 can cause this
situation.
So, this patch checks the done lists in rcar_dmac_chan_get_residue()
and returns zero if the done lists has the argument cookie.
Tested-by: Nguyen Viet Dung <dung.nguyen.aj@renesas.com>
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
1 file changed