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@xxxxxxxxxxxxxxx>
Tested-by: Michael Grzeschik <m.grzeschik@xxxxxxxxxxxxxx>
Reported-by: Michael Grzeschik <m.grzeschik@xxxxxxxxxxxxxx>
Fixes: c96e6725db9d ("usb: dwc3: gadget: Correct the logic for queuing sgs")
Signed-off-by: Thinh Nguyen <Thinh.Nguyen@xxxxxxxxxxxx>
---
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
--
2.28.0
