From: Thinh Nguyen Thinh.Nguyen@synopsys.com
commit 25dda9fc56bd90d45f9a4516bcfa5211e61b4290 upstream.
The driver incorrectly uses req->num_pending_sgs to track both the number of pending and queued SG entries. It only prepares the next request if the previous is done, and it doesn't update num_pending_sgs until there is TRB completion interrupt. This may starve the controller of more TRBs until the num_pending_sgs is decremented.
Fix this by decrementing the num_pending_sgs after they are queued and properly track both num_mapped_sgs and num_queued_sgs.
Fixes: c96e6725db9d ("usb: dwc3: gadget: Correct the logic for queuing sgs") Cc: stable@vger.kernel.org Reported-by: Michael Grzeschik m.grzeschik@pengutronix.de Tested-by: Michael Grzeschik m.grzeschik@pengutronix.de Acked-by: Felipe Balbi balbi@kernel.org Signed-off-by: Thinh Nguyen Thinh.Nguyen@synopsys.com Link: https://lore.kernel.org/r/ba24591dbcaad8f244a3e88bd449bb7205a5aec3.162087406... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/dwc3/gadget.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-)
--- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -1236,6 +1236,7 @@ static int dwc3_prepare_trbs_sg(struct d req->start_sg = sg_next(s);
req->num_queued_sgs++; + req->num_pending_sgs--;
/* * The number of pending SG entries may not correspond to the @@ -1243,7 +1244,7 @@ static int dwc3_prepare_trbs_sg(struct d * don't include unused SG entries. */ if (length == 0) { - req->num_pending_sgs -= req->request.num_mapped_sgs - req->num_queued_sgs; + req->num_pending_sgs = 0; break; }
@@ -2839,15 +2840,15 @@ static int dwc3_gadget_ep_reclaim_trb_sg struct dwc3_trb *trb = &dep->trb_pool[dep->trb_dequeue]; struct scatterlist *sg = req->sg; struct scatterlist *s; - unsigned int pending = req->num_pending_sgs; + unsigned int num_queued = req->num_queued_sgs; unsigned int i; int ret = 0;
- for_each_sg(sg, s, pending, i) { + for_each_sg(sg, s, num_queued, i) { trb = &dep->trb_pool[dep->trb_dequeue];
req->sg = sg_next(s); - req->num_pending_sgs--; + req->num_queued_sgs--;
ret = dwc3_gadget_ep_reclaim_completed_trb(dep, req, trb, event, status, true); @@ -2870,7 +2871,7 @@ static int dwc3_gadget_ep_reclaim_trb_li
static bool dwc3_gadget_ep_request_completed(struct dwc3_request *req) { - return req->num_pending_sgs == 0; + return req->num_pending_sgs == 0 && req->num_queued_sgs == 0; }
static int dwc3_gadget_ep_cleanup_completed_request(struct dwc3_ep *dep, @@ -2879,7 +2880,7 @@ static int dwc3_gadget_ep_cleanup_comple { int ret;
- if (req->num_pending_sgs) + if (req->request.num_mapped_sgs) ret = dwc3_gadget_ep_reclaim_trb_sg(dep, req, event, status); else