On Wed, May 27, 2015 at 05:42:22PM +0000, Winkler, Tomas wrote:

quoted

-----Original Message-----
From: Greg KH [mailto:gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org]
Sent: Wednesday, May 27, 2015 20:29
To: Winkler, Tomas
Cc: arnd-r2nGTMty4D4@public.gmane.org; Stephen Rothwell; linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [char-misc-next 04/11 V2] uuid: extract macros for assigning raw
arrays

On Wed, May 27, 2015 at 05:24:01PM +0000, Winkler, Tomas wrote:

quoted

quoted

On Wed, May 27, 2015 at 06:42:13PM +0300, Tomas Winkler wrote:

quoted

In order for mei client devices to use device id based on uuid we
have to use common types between user space (file2alias.c).
Similarly to vmbus,  mei  uses raw 16 byte array for that.
To leverage on existing infrastructure around uuid_le type
defined in uuid.h we add helper macros to handle conversions between
raw 16 byte array and uuid_{le,be} types.

You aren't adding a helper macro, you are just redefining the existing
macros using a different one.

Not exactly I'm using both the one I've added for device ids and the old one for

all the other flows.

quoted

 But I can't see why this is needed, what

quoted

does this solve that vmbus and other uses of the existing macros don't
need?  In other words, what makes mei so special that it needs a "lower"
level macro than every other subsystem?

It's not special there is actually a lot of code duplication around uuid handling
every subsystem is using their own macros but it can be consolidated around

uuid.h

quoted

So vmbus can use that
Instead of
/*
 * Network GUID
 * {f8615163-df3e-46c5-913f-f2d2f965ed0e}
 */
#define HV_NIC_GUID \
        .guid = { \
                        0x63, 0x51, 0x61, 0xf8, 0x3e, 0xdf, 0xc5, 0x46, \
                        0x91, 0x3f, 0xf2, 0xd2, 0xf9, 0x65, 0xed, 0x0e \
                }

The can use the new macro to make it more readable, something in spirit of:

#define HV_NIC_GUID __UUID_LE(f8615163-df3e-46c5-913f-f2d2f965ed0e)

Why the "__" usage here?  That signifies a "private" namespace, why add
that to the user visible header files?

I take any other suggestion for macro names.  
Not sure how I would reuse the macros if I don't export them both,
second this can be used also by user space.  

But it's not needed at all.

Below is a patch on top of my current tree that makes this patch not
needed.  Any objection to me just applying it instead?

quoted

And are you going to send patches for vmbus and other drivers to fix
everything up to use these new macros?  Someone has to...

Can be done but I cannot test their code and  now I'm busy with splitting the big bus patch :)

Ok, that means no one is ever going to do that work, so it's not a valid
reason to accept such a change.  I prefer the patch below.

thanks,

greg k-h

diff --git a/drivers/nfc/mei_phy.h b/drivers/nfc/mei_phy.h
index a51f8f2685cc..fbfa3e61738f 100644
--- a/drivers/nfc/mei_phy.h
+++ b/drivers/nfc/mei_phy.h

@@ -5,7 +5,7 @@
 #include <net/nfc/hci.h>
 #include <linux/uuid.h>
 
-#define MEI_NFC_UUID __UUID_LE(0x0bb17a78, 0x2a8e, 0x4c50, \
+#define MEI_NFC_UUID UUID_LE(0x0bb17a78, 0x2a8e, 0x4c50, \
 		0x94, 0xd4, 0x50, 0x26, 0x67, 0x23, 0x77, 0x5c)
 #define MEI_NFC_HEADER_SIZE 10
 #define MEI_NFC_MAX_HCI_PAYLOAD 300

diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
index 2d2b2b571d61..048c270822f9 100644
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h

@@ -614,7 +614,7 @@ struct ipack_device_id {
  */
 struct mei_cl_device_id {
 	char name[MEI_CL_NAME_SIZE];
-	__u8 uuid[16];
+	uuid_le uuid;
 	kernel_ulong_t driver_info;
 };
 

diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c
index 62c517f4b592..718b2a29bd43 100644
--- a/scripts/mod/file2alias.c
+++ b/scripts/mod/file2alias.c

@@ -34,6 +34,9 @@ typedef Elf64_Addr	kernel_ulong_t;
 typedef uint32_t	__u32;
 typedef uint16_t	__u16;
 typedef unsigned char	__u8;
+typedef struct {
+	__u8 b[16];
+} uuid_le;
 
 /* Big exception to the "don't include kernel headers into userspace, which
  * even potentially has different endianness and word sizes, since

@@ -131,13 +134,13 @@ static inline void add_wildcard(char *str)
 		strcat(str + len, "*");
 }
 
-static inline void add_uuid(char *str, __u8 uuid[16])
+static inline void add_uuid(char *str, uuid_le uuid)
 {
 	int len = strlen(str);
 	int i;
 
 	for (i = 0; i < 16; i++)
-		sprintf(str + len + (i << 1), "%02x", uuid[i]);
+		sprintf(str + len + (i << 1), "%02x", uuid.b[i]);
 }
 
 /**