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.

Cc: stable@vger.kernel.org Tested-by: Michael Grzeschik m.grzeschik@pengutronix.de Reported-by: Michael Grzeschik m.grzeschik@pengutronix.de Fixes: c96e6725db9d ("usb: dwc3: gadget: Correct the logic for queuing sgs") Signed-off-by: Thinh Nguyen Thinh.Nguyen@synopsys.com --- drivers/usb/dwc3/gadget.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c index 49ca5da5e279..612825a39f82 100644 --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -1244,6 +1244,7 @@ static int dwc3_prepare_trbs_sg(struct dwc3_ep *dep, 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 @@ -1251,7 +1252,7 @@ static int dwc3_prepare_trbs_sg(struct dwc3_ep *dep, * 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; }

@@ -2873,15 +2874,15 @@ static int dwc3_gadget_ep_reclaim_trb_sg(struct dwc3_ep *dep, 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); @@ -2904,7 +2905,7 @@ static int dwc3_gadget_ep_reclaim_trb_linear(struct dwc3_ep *dep,

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, @@ -2913,7 +2914,7 @@ static int dwc3_gadget_ep_cleanup_completed_request(struct dwc3_ep *dep, { 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

base-commit: d9ff1096a840dddea3d5cfa2149ff7da9f499fb2