Re: [vmw_vmci 11/11] Apply the header code to make VMCI build

On Thu, Aug 02, 2012 at 09:50:02PM +0200, Jan Engelhardt wrote:

On Friday 2012-07-27 12:34, Sam Ravnborg wrote:

quoted

quoted

+#ifndef _VMCI_COMMONINT_H_
+#define _VMCI_COMMONINT_H_
+
+#include <linux/printk.h>
+#include <linux/vmw_vmci_defs.h>

Use inverse chrismas tree here.
Longer include lines first, and soret alphabetically when
lines are of the same length.

So that's where unreadable include lists come from.
Depth-first lexicographically-sorted is a lot less hassle,
especially when it comes to merging patches that each
add one different include.

This is applied in many parts of the kernels and has some benefits:
- easy to spot duplicates
- clash is less likely when two commit adds includes
- easy to do so it looks the same across different files

Obviously <linux/*> comes before include <asm/*> as this is
separate blocks of includes.

net/ and arch/x86/ is two places where this is getting the norm,
and these are trendsetters for the rest of the kernel.

quoted

quoted

+/*
+ * Utilility function that checks whether two entities are allowed
+ * to interact. If one of them is restricted, the other one must
+ * be trusted.
+ */
+static inline bool vmci_deny_interaction(uint32_t partOne,
+					 uint32_t partTwo)

The kernel types are u32 not uint32_t - these types belongs in user-space.

Not really. uint32_t is the C99 type for a 32-bit quantity, and I see
absolutely zero reason not to use standardized things.

Found the following somewhere on the net:

On Mon, 29 Nov 2004, Paul Mackerras wrote:

uint32_t is defined to be exactly 32 bits wide, so where's the problem
in using it instead of __u32 in the headers that describe the
user/kernel interface?  (Ditto for uint{8,16,64}_t, of course.

Ok, this discussion has gone on for too long anyway, but let's make it
easier for everybody. The kernel uses u8/u16/u32 because:

	- the kernel should not depend on, or pollute user-space naming.
	  YOU MUST NOT USE "uint32_t" when that may not be defined, and
	  user-space rules for when it is defined are arcane and totally
	  arbitrary.
...

See http://yarchive.net/comp/linux/kernel_headers.html for additional
rationale. (Second mail listed).

	Sam

On Thursday 2012-08-02 22:22, Sam Ravnborg wrote:

quoted

On Friday 2012-07-27 12:34, Sam Ravnborg wrote:

quoted

quoted

+#ifndef _VMCI_COMMONINT_H_
+#define _VMCI_COMMONINT_H_
+
+#include <linux/printk.h>
+#include <linux/vmw_vmci_defs.h>

Use inverse chrismas tree here.
Longer include lines first, and soret alphabetically when
lines are of the same length.

So that's where unreadable include lists come from.
Depth-first lexicographically-sorted is a lot less hassle,
especially when it comes to merging patches that each
add one different include.

This is applied in many parts of the kernels and has some benefits:
- easy to spot duplicates
- clash is less likely when two commit adds includes

Sorting already addresses the two, the christmas thing (for
files in a single dir) seems like adding no extra value.

quoted

quoted

The kernel types are u32 not uint32_t - these types belongs in user-space.

Found the following somewhere on the net:

|	- the kernel should not depend on, or pollute user-space naming.
|	  YOU MUST NOT USE "uint32_t" when that may not be defined, and
|	  user-space rules for when it is defined are arcane and totally
|	  arbitrary.

I can see the reasoning for header files, but it seems
irrelevant for code, in particular .c files, that never
practically get exposed to userspace.