A simple trick to avoid "goto" statement

Error handling in C is sometimes done by using goto and labels. One of examples in the Linux kernel:

static struct avc_node *avc_alloc_node(void)
{
    struct avc_node *node;

    node = kmem_cache_zalloc(avc_node_cachep, GFP_ATOMIC);
    if (!node)  
        goto out;

    INIT_RCU_HEAD(&node->rhead);
    INIT_HLIST_NODE(&node->list);
    avc_cache_stats_incr(allocations);

    if (atomic_inc_return(&avc_cache.active_nodes) > avc_cache_threshold)
        avc_reclaim_node();
   
out:
    return node;
}

There's a trick with the usage of do/while construction that allows to write the same without using goto label. The idea is presented on below:

// with goto label
if (!bar()) {
    goto error;
}
someValue = baz();
error:

// with do/while construction
do {
    if (!bar()) {
        break;
    }
    someValue = baz();
} while (0);

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