diff options
| -rw-r--r-- | Documentation/CodingStyle | 27 |
1 files changed, 22 insertions, 5 deletions
diff --git a/Documentation/CodingStyle b/Documentation/CodingStyle index 9f28b140dc89..618a33c940df 100644 --- a/Documentation/CodingStyle +++ b/Documentation/CodingStyle @@ -392,7 +392,12 @@ The goto statement comes in handy when a function exits from multiple locations and some common work such as cleanup has to be done. If there is no cleanup needed then just return directly. -The rationale is: +Choose label names which say what the goto does or why the goto exists. An +example of a good name could be "out_buffer:" if the goto frees "buffer". Avoid +using GW-BASIC names like "err1:" and "err2:". Also don't name them after the +goto location like "err_kmalloc_failed:" + +The rationale for using gotos is: - unconditional statements are easier to understand and follow - nesting is reduced @@ -403,9 +408,10 @@ The rationale is: int fun(int a) { int result = 0; - char *buffer = kmalloc(SIZE); + char *buffer; - if (buffer == NULL) + buffer = kmalloc(SIZE, GFP_KERNEL); + if (!buffer) return -ENOMEM; if (condition1) { @@ -413,14 +419,25 @@ int fun(int a) ... } result = 1; - goto out; + goto out_buffer; } ... -out: +out_buffer: kfree(buffer); return result; } +A common type of bug to be aware of it "one err bugs" which look like this: + +err: + kfree(foo->bar); + kfree(foo); + return ret; + +The bug in this code is that on some exit paths "foo" is NULL. Normally the +fix for this is to split it up into two error labels "err_bar:" and "err_foo:". + + Chapter 8: Commenting Comments are good, but there is also a danger of over-commenting. NEVER |