patch "usb: dwc3: gadget: Properly track pending and queued SG" added to usb-linus
From: <gregkh@linuxfoundation.org>
Date: 2021-05-21 12:26:28
Subsystem:
designware usb3 drd ip driver, the rest, usb subsystem · Maintainers:
Thinh Nguyen, Linus Torvalds, Greg Kroah-Hartman
This is a note to let you know that I've just added the patch titled
usb: dwc3: gadget: Properly track pending and queued SG
to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
From 25dda9fc56bd90d45f9a4516bcfa5211e61b4290 Mon Sep 17 00:00:00 2001
From: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Date: Wed, 12 May 2021 20:17:09 -0700
Subject: usb: dwc3: gadget: Properly track pending and queued SG
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: <redacted>
Reported-by: Michael Grzeschik <redacted>
Tested-by: Michael Grzeschik <redacted>
Acked-by: Felipe Balbi <balbi@kernel.org>
Signed-off-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Link: https://lore.kernel.org/r/ba24591dbcaad8f244a3e88bd449bb7205a5aec3.1620874069.git.Thinh.Nguyen@synopsys.com (local)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
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
--
2.31.1