| Message ID | 1576123160-28931-1-git-send-email-peter.chen@nxp.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/1] usb: gadget: f_fs: set req->num_sgs as 0 for sync io mode | expand |
Hi, Peter Chen <peter.chen@nxp.com> writes: > The UDC core uses req->num_sgs to judge if scatter buffer list is used. > Eg: usb_gadget_map_request_by_dev. For f_fs sync io mode, the request > is re-used for each request, so if the 1st request->length > PAGE_SIZE, > and the 2nd request->length is < PAGE_SIZE, the f_fs uses the 1st > req->num_sgs for the 2nd request, it causes the UDC core get the wrong > req->num_sgs value (The 2nd request doesn't use sg). > > We set req->num_sgs as 0 for each request at non-sg transfer case to > fix it. The patch, however, is *removing* initialization to 0... > Cc: Jun Li <jun.li@nxp.com> > Cc: stable <stable@vger.kernel.org> > Fixes: 772a7a724f69 ("usb: gadget: f_fs: Allow scatter-gather buffers") > Signed-off-by: Peter Chen <peter.chen@nxp.com> > --- > drivers/usb/gadget/function/f_fs.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c > index eedd926cc578..b5a1bfc2fc7e 100644 > --- a/drivers/usb/gadget/function/f_fs.c > +++ b/drivers/usb/gadget/function/f_fs.c > @@ -1106,7 +1106,6 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data) > req->num_sgs = io_data->sgt.nents; > } else { > req->buf = data; > - req->num_sgs = 0; ... this doesn't seem to match your commit log. Care to explain?
> Peter Chen <peter.chen@nxp.com> writes: > > The UDC core uses req->num_sgs to judge if scatter buffer list is used. > > Eg: usb_gadget_map_request_by_dev. For f_fs sync io mode, the request > > is re-used for each request, so if the 1st request->length > > > PAGE_SIZE, and the 2nd request->length is < PAGE_SIZE, the f_fs uses > > the 1st > > req->num_sgs for the 2nd request, it causes the UDC core get the wrong > > req->num_sgs value (The 2nd request doesn't use sg). > > > > We set req->num_sgs as 0 for each request at non-sg transfer case to > > fix it. > > The patch, however, is *removing* initialization to 0... > > > Cc: Jun Li <jun.li@nxp.com> > > Cc: stable <stable@vger.kernel.org> > > Fixes: 772a7a724f69 ("usb: gadget: f_fs: Allow scatter-gather > > buffers") > > Signed-off-by: Peter Chen <peter.chen@nxp.com> > > --- > > drivers/usb/gadget/function/f_fs.c | 1 - > > 1 file changed, 1 deletion(-) > > > > diff --git a/drivers/usb/gadget/function/f_fs.c > > b/drivers/usb/gadget/function/f_fs.c > > index eedd926cc578..b5a1bfc2fc7e 100644 > > --- a/drivers/usb/gadget/function/f_fs.c > > +++ b/drivers/usb/gadget/function/f_fs.c > > @@ -1106,7 +1106,6 @@ static ssize_t ffs_epfile_io(struct file *file, struct > ffs_io_data *io_data) > > req->num_sgs = io_data->sgt.nents; > > } else { > > req->buf = data; > > - req->num_sgs = 0; > > ... this doesn't seem to match your commit log. Care to explain? > Sorry, I did not check the patch when I formatted it. I need to pay more attention to it next time. I will send it again. Peter
diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c index eedd926cc578..b5a1bfc2fc7e 100644 --- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -1106,7 +1106,6 @@ static ssize_t ffs_epfile_io(struct file *file, struct ffs_io_data *io_data) req->num_sgs = io_data->sgt.nents; } else { req->buf = data; - req->num_sgs = 0; } req->length = data_len;
The UDC core uses req->num_sgs to judge if scatter buffer list is used. Eg: usb_gadget_map_request_by_dev. For f_fs sync io mode, the request is re-used for each request, so if the 1st request->length > PAGE_SIZE, and the 2nd request->length is < PAGE_SIZE, the f_fs uses the 1st req->num_sgs for the 2nd request, it causes the UDC core get the wrong req->num_sgs value (The 2nd request doesn't use sg). We set req->num_sgs as 0 for each request at non-sg transfer case to fix it. Cc: Jun Li <jun.li@nxp.com> Cc: stable <stable@vger.kernel.org> Fixes: 772a7a724f69 ("usb: gadget: f_fs: Allow scatter-gather buffers") Signed-off-by: Peter Chen <peter.chen@nxp.com> --- drivers/usb/gadget/function/f_fs.c | 1 - 1 file changed, 1 deletion(-)