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authorAmit Virdi <amit.virdi@st.com>2015-01-13 14:27:20 +0530
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-01-27 07:52:32 -0800
commit94b762f0128bb14c2bb284e9ce1f5400a458a0c1 (patch)
tree770a12a0f0762b943c91b95fa9f5630f4c82e348 /drivers/usb/dwc3
parent911d93746fec9885987065e0c72ad30cf7a20922 (diff)
downloadlinux-linaro-stable-94b762f0128bb14c2bb284e9ce1f5400a458a0c1.tar.gz
usb: dwc3: gadget: Fix TRB preparation during SG
commit ec512fb8e5611fed1df2895f90317ce6797d6b32 upstream. When scatter gather (SG) is used, multiple TRBs are prepared from one DWC3 request (dwc3_request). So while preparing TRBs, the 'last' flag should be set only when it is the last TRB being prepared from the last dwc3_request entry. The current implementation uses list_is_last to check if the dwc3_request is the last entry from the request_list. However, list_is_last returns false for the last entry too. This is because, while preparing the first TRB from a request, the function dwc3_prepare_one_trb modifies the request's next and prev pointers while moving the URB to req_queued. Hence, list_is_last always returns false no matter what. The correct way is not to access the modified pointers of dwc3_request but to use list_empty macro instead. Fixes: e5ba5ec833aa (usb: dwc3: gadget: fix scatter gather implementation) Signed-off-by: Amit Virdi <amit.virdi@st.com> Signed-off-by: Felipe Balbi <balbi@ti.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/dwc3')
-rw-r--r--drivers/usb/dwc3/gadget.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 8f8e75e392de..a8a2eb5158b7 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -907,8 +907,7 @@ static void dwc3_prepare_trbs(struct dwc3_ep *dep, bool starting)
if (i == (request->num_mapped_sgs - 1) ||
sg_is_last(s)) {
- if (list_is_last(&req->list,
- &dep->request_list))
+ if (list_empty(&dep->request_list))
last_one = true;
chain = false;
}