diff mbox series

[2/8] usb: gadget: add anonymous definition in some struct for trace purpose

Message ID 20230914100302.30274-3-quic_linyyuan@quicinc.com (mailing list archive)
State Rejected
Headers show
Series usb: gadget: reduce usb gadget trace event buffer usage | expand

Commit Message

Linyu Yuan Sept. 14, 2023, 10:02 a.m. UTC
Some UDC trace event will save usb udc information, but it use one int
size buffer to save one bit information of usb udc, it is wast trace
buffer.

Add anonymous union which have one u32 member can be used by trace event
during fast assign stage to save more entries with same trace ring buffer
size.

Signed-off-by: Linyu Yuan <quic_linyyuan@quicinc.com>
---
 include/linux/usb/gadget.h | 113 +++++++++++++++++++++++--------------
 1 file changed, 72 insertions(+), 41 deletions(-)

Comments

Alan Stern Sept. 14, 2023, 2:54 p.m. UTC | #1
You didn't include the version number in the Subject: line.  Undoubtedly 
Greg's automatic error checker will warn you about this.  Unless the 
version number is clearly marked for each patch, it's difficult for his 
programs to tell which email message contains the most recent version.

On Thu, Sep 14, 2023 at 06:02:56PM +0800, Linyu Yuan wrote:
> Some UDC trace event will save usb udc information, but it use one int
> size buffer to save one bit information of usb udc, it is wast trace
> buffer.
> 
> Add anonymous union which have one u32 member can be used by trace event
> during fast assign stage to save more entries with same trace ring buffer
> size.
> 
> Signed-off-by: Linyu Yuan <quic_linyyuan@quicinc.com>
> ---

And you didn't include the version change information here, below the 
"---" line.

Apart from that, this is a _lot_ better than before!  I don't know if 
Greg will think this change is worth merging, but at least now it's 
possible to read the code and understand what's going on.

Alan Stern
Linyu Yuan Sept. 15, 2023, 1:02 a.m. UTC | #2
On 9/14/2023 10:54 PM, Alan Stern wrote:
> You didn't include the version number in the Subject: line.  Undoubtedly
> Greg's automatic error checker will warn you about this.  Unless the
> version number is clearly marked for each patch, it's difficult for his
> programs to tell which email message contains the most recent version.
>
> On Thu, Sep 14, 2023 at 06:02:56PM +0800, Linyu Yuan wrote:
>> Some UDC trace event will save usb udc information, but it use one int
>> size buffer to save one bit information of usb udc, it is wast trace
>> buffer.
>>
>> Add anonymous union which have one u32 member can be used by trace event
>> during fast assign stage to save more entries with same trace ring buffer
>> size.
>>
>> Signed-off-by: Linyu Yuan <quic_linyyuan@quicinc.com>
>> ---
> And you didn't include the version change information here, below the
> "---" line.
>
> Apart from that, this is a _lot_ better than before!  I don't know if
> Greg will think this change is worth merging, but at least now it's
> possible to read the code and understand what's going on.


according Steven's comment, maybe will always save data in little endian 
at trace event

fast assign stage.

it will add definition of bit field back.


>
> Alan Stern
Alan Stern Sept. 15, 2023, 1:51 a.m. UTC | #3
On Fri, Sep 15, 2023 at 09:02:48AM +0800, Linyu Yuan wrote:
> 
> On 9/14/2023 10:54 PM, Alan Stern wrote:
> > You didn't include the version number in the Subject: line.  Undoubtedly
> > Greg's automatic error checker will warn you about this.  Unless the
> > version number is clearly marked for each patch, it's difficult for his
> > programs to tell which email message contains the most recent version.
> > 
> > On Thu, Sep 14, 2023 at 06:02:56PM +0800, Linyu Yuan wrote:
> > > Some UDC trace event will save usb udc information, but it use one int
> > > size buffer to save one bit information of usb udc, it is wast trace
> > > buffer.
> > > 
> > > Add anonymous union which have one u32 member can be used by trace event
> > > during fast assign stage to save more entries with same trace ring buffer
> > > size.
> > > 
> > > Signed-off-by: Linyu Yuan <quic_linyyuan@quicinc.com>
> > > ---
> > And you didn't include the version change information here, below the
> > "---" line.
> > 
> > Apart from that, this is a _lot_ better than before!  I don't know if
> > Greg will think this change is worth merging, but at least now it's
> > possible to read the code and understand what's going on.
> 
> 
> according Steven's comment, maybe will always save data in little endian at
> trace event
> 
> fast assign stage.
> 
> it will add definition of bit field back.

Yes, that would be even better because you wouldn't have to change the 
definition of struct usb_gadget or struct usb_endpoint at all.  The fast 
assign stage can simply do:

	__entry->dw1 = (g->sg_supported << 0) |
			(g->is_otg << 1) |
			...

and then you can easily access the individual bits in __entry.  It 
wouldn't be as fast but it would still save a lot of space.

Alan Stern
Linyu Yuan Sept. 15, 2023, 1:56 a.m. UTC | #4
On 9/15/2023 9:51 AM, Alan Stern wrote:
> On Fri, Sep 15, 2023 at 09:02:48AM +0800, Linyu Yuan wrote:
>> On 9/14/2023 10:54 PM, Alan Stern wrote:
>>> You didn't include the version number in the Subject: line.  Undoubtedly
>>> Greg's automatic error checker will warn you about this.  Unless the
>>> version number is clearly marked for each patch, it's difficult for his
>>> programs to tell which email message contains the most recent version.
>>>
>>> On Thu, Sep 14, 2023 at 06:02:56PM +0800, Linyu Yuan wrote:
>>>> Some UDC trace event will save usb udc information, but it use one int
>>>> size buffer to save one bit information of usb udc, it is wast trace
>>>> buffer.
>>>>
>>>> Add anonymous union which have one u32 member can be used by trace event
>>>> during fast assign stage to save more entries with same trace ring buffer
>>>> size.
>>>>
>>>> Signed-off-by: Linyu Yuan <quic_linyyuan@quicinc.com>
>>>> ---
>>> And you didn't include the version change information here, below the
>>> "---" line.
>>>
>>> Apart from that, this is a _lot_ better than before!  I don't know if
>>> Greg will think this change is worth merging, but at least now it's
>>> possible to read the code and understand what's going on.
>>
>> according Steven's comment, maybe will always save data in little endian at
>> trace event
>>
>> fast assign stage.
>>
>> it will add definition of bit field back.
> Yes, that would be even better because you wouldn't have to change the
> definition of struct usb_gadget or struct usb_endpoint at all.  The fast
> assign stage can simply do:
>
> 	__entry->dw1 = (g->sg_supported << 0) |
> 			(g->is_otg << 1) |
> 			...
>
> and then you can easily access the individual bits in __entry.  It
> wouldn't be as fast but it would still save a lot of space.


how about __entry->dw1 = cpu_to_le32(g->dw1) ?




>
> Alan Stern
diff mbox series

Patch

diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
index 75bda0783395..4894f256df55 100644
--- a/include/linux/usb/gadget.h
+++ b/include/linux/usb/gadget.h
@@ -41,6 +41,7 @@  struct usb_ep;
  * @num_sgs: number of SG entries
  * @num_mapped_sgs: number of SG entries mapped to DMA (internal)
  * @length: Length of that data
+ * @dw1: trace event purpose
  * @stream_id: The stream id, when USB3.0 bulk streams are being used
  * @is_last: Indicates if this is the last request of a stream_id before
  *	switching to a different stream (required for DWC3 controllers).
@@ -105,12 +106,17 @@  struct usb_request {
 	unsigned		num_sgs;
 	unsigned		num_mapped_sgs;
 
-	unsigned		stream_id:16;
-	unsigned		is_last:1;
-	unsigned		no_interrupt:1;
-	unsigned		zero:1;
-	unsigned		short_not_ok:1;
-	unsigned		dma_mapped:1;
+	union {
+		struct {
+			u32	stream_id:16;
+			u32	is_last:1;
+			u32	no_interrupt:1;
+			u32	zero:1;
+			u32	short_not_ok:1;
+			u32	dma_mapped:1;
+		} __packed;
+		u32		dw1;
+	};
 
 	void			(*complete)(struct usb_ep *ep,
 					struct usb_request *req);
@@ -163,13 +169,13 @@  struct usb_ep_ops {
  * @dir_out:Endpoint supports OUT direction.
  */
 struct usb_ep_caps {
-	unsigned type_control:1;
-	unsigned type_iso:1;
-	unsigned type_bulk:1;
-	unsigned type_int:1;
-	unsigned dir_in:1;
-	unsigned dir_out:1;
-};
+	u8	type_control:1;
+	u8	type_iso:1;
+	u8	type_bulk:1;
+	u8	type_int:1;
+	u8	dir_in:1;
+	u8	dir_out:1;
+} __packed;
 
 #define USB_EP_CAPS_TYPE_CONTROL     0x01
 #define USB_EP_CAPS_TYPE_ISO         0x02
@@ -199,6 +205,9 @@  struct usb_ep_caps {
  * @caps:The structure describing types and directions supported by endpoint.
  * @enabled: The current endpoint enabled/disabled state.
  * @claimed: True if this endpoint is claimed by a function.
+ * @dw1: trace event purpose
+ * @dw2: trace event purpose
+ * @dw3: trace event purpose
  * @maxpacket:The maximum packet size used on this endpoint.  The initial
  *	value can sometimes be reduced (hardware allowing), according to
  *	the endpoint descriptor used to configure the endpoint.
@@ -228,15 +237,30 @@  struct usb_ep {
 	const char		*name;
 	const struct usb_ep_ops	*ops;
 	struct list_head	ep_list;
-	struct usb_ep_caps	caps;
-	bool			claimed;
-	bool			enabled;
-	unsigned		maxpacket:16;
-	unsigned		maxpacket_limit:16;
-	unsigned		max_streams:16;
-	unsigned		mult:2;
-	unsigned		maxburst:5;
-	u8			address;
+	union {
+		struct {
+			u32	maxpacket:16;
+			u32	maxpacket_limit:16;
+		} __packed;
+		u32	dw1;
+	};
+	union {
+		struct {
+			u32	max_streams:16;
+			u32	mult:2;
+			u32	maxburst:5;
+		} __packed;
+		u32	dw2;
+	};
+	union {
+		struct {
+			struct usb_ep_caps	caps;
+			u8			claimed:1;
+			u8			enabled:1;
+			u8			address;
+		} __packed;
+		u32	dw3;
+	};
 	const struct usb_endpoint_descriptor	*desc;
 	const struct usb_ss_ep_comp_descriptor	*comp_desc;
 };
@@ -357,6 +381,7 @@  struct usb_gadget_ops {
  * @in_epnum: last used in ep number
  * @mA: last set mA value
  * @otg_caps: OTG capabilities of this gadget.
+ * @dw1: trace event purpose
  * @sg_supported: true if we can handle scatter-gather
  * @is_otg: True if the USB device port uses a Mini-AB jack, so that the
  *	gadget driver must provide a USB OTG descriptor.
@@ -432,25 +457,31 @@  struct usb_gadget {
 	unsigned			mA;
 	struct usb_otg_caps		*otg_caps;
 
-	unsigned			sg_supported:1;
-	unsigned			is_otg:1;
-	unsigned			is_a_peripheral:1;
-	unsigned			b_hnp_enable:1;
-	unsigned			a_hnp_support:1;
-	unsigned			a_alt_hnp_support:1;
-	unsigned			hnp_polling_support:1;
-	unsigned			host_request_flag:1;
-	unsigned			quirk_ep_out_aligned_size:1;
-	unsigned			quirk_altset_not_supp:1;
-	unsigned			quirk_stall_not_supp:1;
-	unsigned			quirk_zlp_not_supp:1;
-	unsigned			quirk_avoids_skb_reserve:1;
-	unsigned			is_selfpowered:1;
-	unsigned			deactivated:1;
-	unsigned			connected:1;
-	unsigned			lpm_capable:1;
-	unsigned			wakeup_capable:1;
-	unsigned			wakeup_armed:1;
+	union {
+		struct {
+			u32		sg_supported:1;
+			u32		is_otg:1;
+			u32		is_a_peripheral:1;
+			u32		b_hnp_enable:1;
+			u32		a_hnp_support:1;
+			u32		a_alt_hnp_support:1;
+			u32		hnp_polling_support:1;
+			u32		host_request_flag:1;
+			u32		quirk_ep_out_aligned_size:1;
+			u32		quirk_altset_not_supp:1;
+			u32		quirk_stall_not_supp:1;
+			u32		quirk_zlp_not_supp:1;
+			u32		quirk_avoids_skb_reserve:1;
+			u32		is_selfpowered:1;
+			u32		deactivated:1;
+			u32		connected:1;
+			u32		lpm_capable:1;
+			u32		wakeup_capable:1;
+			u32		wakeup_armed:1;
+		} __packed;
+
+		u32			dw1;
+	};
 	int				irq;
 	int				id_number;
 };