The new command \src was introduced for preliminary hyperlink generation
which points to Linux kernel source code. At present, stable/linux.git
was referred:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
We might switch to specific LTS kernels once requested.
This patch uses the relative path to Linux kernel headers in source tree
rather than what they are usually inclused in LKM. It would be great to
introduce \href with appropriate hyperlinks to Linux kernel tree.
Both <linux/module.h> and <linux/kernel.h> are essential headers, and
LKM should include them. Here, we do not use the fully qualified path
specifying the headers.
This patch enforces the annotations by means of the following:
* \cpp : C/C++ code, functions, variables, macros, symbols
* \sh : commands, executable files
* \verb : path and filenames
The proc_ops structure is defined in <include/linux/proc_fs.h> since
Linux v5.6+.
In older kernels, file_operations structure is used for custom hooks in
/proc file system. However, it contains some members that are unnecessary
in VFS, and every time VFS expands file_operations set, /proc code comes
bloated.
On the other hand, not only the space, but also some operations were
saved by this structure to improve its performance.
For the example module hello_5, the book showed the incorrect output
in corresponding with its execution results.
In addition, this patch changes from myintArray[2] = {-1, -1} to
myintArray[2] = {420, 420}, which help the readers distinguish from
the kernel messages.
