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Use TikZ to re-draw seq_file graph

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25077667 2021-07-23 02:10:57 +08:00
parent 35ac926de5
commit 245ac0298e
2 changed files with 27 additions and 1 deletions
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img/seq_file.png
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lkmpg.tex
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@ -5,6 +5,16 @@
\usepackage{graphicx}
\usepackage{fancyhdr}
% tikz settings
\usepackage{tikz}
\usetikzlibrary{shapes.geometric, arrows, shadows, decorations.text}
\tikzstyle{startstop} = [rectangle, rounded corners, minimum width=3cm, minimum height=1cm,text centered, draw=black, fill=red!30, drop shadow]
\tikzstyle{io} = [trapezium, trapezium left angle=70, trapezium right angle=110, minimum width=3cm, minimum height=1cm, text centered, draw=black, fill=blue!30]
\tikzstyle{process} = [rectangle, minimum width=3cm, minimum height=1cm, text centered, text width=3cm, draw=black, fill=orange!30]
\tikzstyle{decision} = [diamond, minimum width=1cm, minimum height=1cm, text centered, draw=black, fill=green!30]
\tikzstyle{arrow} = [thick,->,>=stealth]
\tikzstyle{line} = [draw, -latex']
% packages for code
\usepackage{verbatim}
\usepackage{minted}
@ -733,7 +743,23 @@ non NULL value, the function next() is called. This function is an iterator, the
BE CARREFUL: when a sequence is finished, another one starts. That means that at the end of function stop(), the function start() is called again. This loop finishes when the function start() returns NULL. You can see a scheme of this in the figure "How seq\_file works".
\begin{center}
\includegraphics[width=.9\linewidth]{img/seq_file.png}
\begin{tikzpicture}[node distance=2cm, thick]
\node (start) [startstop] {start() treatment};
\node (branch1) [decision, below of=start, yshift=-1cm] {return is NULL?};
\node (emptynode) [right of=branch1, xshift=2cm] {Yes};
\node (next) [process, below of=branch1, yshift=-1cm] {next() treatment};
\node (branch2) [decision, below of=next, yshift=-1cm] {return is NULL?};
\node (stop) [startstop, below of=branch2, yshift=-1cm] {stop() treatment};
\draw [->] (start) -- (branch1);
\draw [->] (branch1) -- node[anchor=east] {} (emptynode);
\draw [->] (branch1) -- node[left=2em, anchor=south] {No} (next);
\draw [->] (next) -- (branch2);
\draw [->] (branch2.west) to [out=135, in=-135, bend left=45] node [left] {No} (next.west);
\draw [->] (branch2) -- node[left=2em, anchor=south] {Yes} (stop);
\draw [->] (stop.west) to [out=135, in=-135] node [left] {} (start.west);
\end{tikzpicture}
\end{center}
Seq\_file provides basic functions for proc\_ops, as seq\_read, seq\_lseek, and some others. But nothing to write in the /proc file. Of course, you can still use the same way as in the previous example.