Prefer early returns

When a function can determine an early result based on input validation or special cases, return immediately rather than assigning to a temporary variable and having a single exit point. Early returns reduce nesting, improve readability, and often result in more efficient code by making guard conditions more visible.

// Recommended:
static int convert_prio(const int prio)
{
    if (prio == CPUPRI_INVALID)
        return CPUPRI_INVALID;
    
    // Continue with normal processing
    return prio - 40;
}

// Avoid:
static int convert_prio(int prio)
{
    int cpupri;

    if (prio == CPUPRI_INVALID)
        cpupri = CPUPRI_INVALID;
    else
        cpupri = prio - 40;
        
    return cpupri;
}

Early validation helps prevent unnecessary operations when preconditions aren’t met, and results in flatter code that’s easier to understand and maintain. Using const for parameters that won’t be modified also improves code clarity and can help the compiler optimize.