2017-04-04 05:18:13

by Michał Mirosław

Subject: [PATCH] NFC: pn533: use constant off-stack buffer for sending acks

This fixes following WARNing:

usb 3-2.4.1: NFC: Exchanging data failed (error 0x13)
llcp: nfc_llcp_recv: err -5
llcp: nfc_llcp_symm_timer: SYMM timeout
------------[ cut here ]------------
WARNING: CPU: 1 PID: 26397 at .../drivers/usb/core/hcd.c:1584 usb_hcd_map_urb_for_dma+0x370/0x550
transfer buffer not dma capable
[...]
Workqueue: events nfc_llcp_timeout_work [nfc]
Call Trace:
? dump_stack+0x46/0x5a
? __warn+0xb9/0xe0
? warn_slowpath_fmt+0x5a/0x80
? usb_hcd_map_urb_for_dma+0x370/0x550
? usb_hcd_submit_urb+0x2fb/0xa60
? dequeue_entity+0x3f2/0xc30
? pn533_usb_send_ack+0x5d/0x80 [pn533_usb]
? pn533_usb_abort_cmd+0x13/0x20 [pn533_usb]
? pn533_dep_link_down+0x32/0x70 [pn533]
? nfc_dep_link_down+0x87/0xd0 [nfc]
[...]
usb 3-2.4.1: NFC: Exchanging data failed (error 0x13)
llcp: nfc_llcp_recv: err -5
llcp: nfc_llcp_symm_timer: SYMM timeout

Signed-off-by: Michał Mirosław <[email protected]>
---

Patch against stable linux-4.10.8.

---
drivers/nfc/pn533/i2c.c | 7 ++++---
drivers/nfc/pn533/usb.c | 7 ++++---
2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/nfc/pn533/i2c.c b/drivers/nfc/pn533/i2c.c
index 1dc89248e58e..35f410797fe4 100644
--- a/drivers/nfc/pn533/i2c.c
+++ b/drivers/nfc/pn533/i2c.c
@@ -49,10 +49,11 @@ struct pn533_i2c_phy {

static int pn533_i2c_send_ack(struct pn533 *dev, gfp_t flags)
{
- struct pn533_i2c_phy *phy = dev->phy;
- struct i2c_client *client = phy->i2c_dev;
- u8 ack[6] = {0x00, 0x00, 0xff, 0x00, 0xff, 0x00};
+ static const u8 ack[6] = {0x00, 0x00, 0xff, 0x00, 0xff, 0x00};
/* spec 6.2.1.3: Preamble, SoPC (2), ACK Code (2), Postamble */
+
+ struct pn533_i2c_phy *phy = dev->phy;
+ struct i2c_client *client = phy->i2c_dev;
int rc;

rc = i2c_master_send(client, ack, 6);
diff --git a/drivers/nfc/pn533/usb.c b/drivers/nfc/pn533/usb.c
index 33ed78be2750..09e1db8e8dc3 100644
--- a/drivers/nfc/pn533/usb.c
+++ b/drivers/nfc/pn533/usb.c
@@ -147,12 +147,13 @@ static int pn533_submit_urb_for_ack(struct pn533_usb_phy *phy, gfp_t flags)

static int pn533_usb_send_ack(struct pn533 *dev, gfp_t flags)
{
- struct pn533_usb_phy *phy = dev->phy;
- u8 ack[6] = {0x00, 0x00, 0xff, 0x00, 0xff, 0x00};
+ static const u8 ack[6] = {0x00, 0x00, 0xff, 0x00, 0xff, 0x00};
/* spec 7.1.1.3: Preamble, SoPC (2), ACK Code (2), Postamble */
+
+ struct pn533_usb_phy *phy = dev->phy;
int rc;

- phy->out_urb->transfer_buffer = ack;
+ phy->out_urb->transfer_buffer = (u8 *)ack;
phy->out_urb->transfer_buffer_length = sizeof(ack);
rc = usb_submit_urb(phy->out_urb, flags);

--
2.11.0

2017-04-05 08:22:28

by Samuel Ortiz

Subject: Re: [PATCH] NFC: pn533: use constant off-stack buffer for sending acks

Hi Michał,

On Tue, Apr 04, 2017 at 07:09:10AM +0200, Michał Mirosław wrote:
> This fixes following WARNing:
>
> usb 3-2.4.1: NFC: Exchanging data failed (error 0x13)
> llcp: nfc_llcp_recv: err -5
> llcp: nfc_llcp_symm_timer: SYMM timeout
> ------------[ cut here ]------------
> WARNING: CPU: 1 PID: 26397 at .../drivers/usb/core/hcd.c:1584 usb_hcd_map_urb_for_dma+0x370/0x550
> transfer buffer not dma capable
> [...]
> Workqueue: events nfc_llcp_timeout_work [nfc]
> Call Trace:
> ? dump_stack+0x46/0x5a
> ? __warn+0xb9/0xe0
> ? warn_slowpath_fmt+0x5a/0x80
> ? usb_hcd_map_urb_for_dma+0x370/0x550
> ? usb_hcd_submit_urb+0x2fb/0xa60
> ? dequeue_entity+0x3f2/0xc30
> ? pn533_usb_send_ack+0x5d/0x80 [pn533_usb]
> ? pn533_usb_abort_cmd+0x13/0x20 [pn533_usb]
> ? pn533_dep_link_down+0x32/0x70 [pn533]
> ? nfc_dep_link_down+0x87/0xd0 [nfc]
> [...]
> usb 3-2.4.1: NFC: Exchanging data failed (error 0x13)
> llcp: nfc_llcp_recv: err -5
> llcp: nfc_llcp_symm_timer: SYMM timeout
>
> Signed-off-by: Michał Mirosław <[email protected]>
> ---
>
> Patch against stable linux-4.10.8.
Could you please rebase against nfc-next ?


> diff --git a/drivers/nfc/pn533/i2c.c b/drivers/nfc/pn533/i2c.c
> index 1dc89248e58e..35f410797fe4 100644
> --- a/drivers/nfc/pn533/i2c.c
> +++ b/drivers/nfc/pn533/i2c.c
> @@ -49,10 +49,11 @@ struct pn533_i2c_phy {
>
> static int pn533_i2c_send_ack(struct pn533 *dev, gfp_t flags)
> {
> - struct pn533_i2c_phy *phy = dev->phy;
> - struct i2c_client *client = phy->i2c_dev;
> - u8 ack[6] = {0x00, 0x00, 0xff, 0x00, 0xff, 0x00};
> + static const u8 ack[6] = {0x00, 0x00, 0xff, 0x00, 0xff, 0x00};
> /* spec 6.2.1.3: Preamble, SoPC (2), ACK Code (2), Postamble */
> +
> + struct pn533_i2c_phy *phy = dev->phy;
> + struct i2c_client *client = phy->i2c_dev;
Can we please not move those 2 declarations to make the patch less
verbose ?


> diff --git a/drivers/nfc/pn533/usb.c b/drivers/nfc/pn533/usb.c
> index 33ed78be2750..09e1db8e8dc3 100644
> --- a/drivers/nfc/pn533/usb.c
> +++ b/drivers/nfc/pn533/usb.c
> @@ -147,12 +147,13 @@ static int pn533_submit_urb_for_ack(struct pn533_usb_phy *phy, gfp_t flags)
>
> static int pn533_usb_send_ack(struct pn533 *dev, gfp_t flags)
> {
> - struct pn533_usb_phy *phy = dev->phy;
> - u8 ack[6] = {0x00, 0x00, 0xff, 0x00, 0xff, 0x00};
> + static const u8 ack[6] = {0x00, 0x00, 0xff, 0x00, 0xff, 0x00};
> /* spec 7.1.1.3: Preamble, SoPC (2), ACK Code (2), Postamble */
> +
> + struct pn533_usb_phy *phy = dev->phy;
Ditto.

Cheers,
Samuel.