#include <linux/slab.h> #include <linux/spinlock.h> #include <linux/once.h> #include <linux/random.h> struct once_work { struct work_struct work; struct static_key *key; }; static void once_deferred(struct work_struct *w) { struct once_work *work; work = container_of(w, struct once_work, work); BUG_ON(!static_key_enabled(work->key)); static_key_slow_dec(work->key); kfree(work); } static void once_disable_jump(struct static_key *key) { struct once_work *w; w = kmalloc(sizeof(*w), GFP_ATOMIC); if (!w) return; INIT_WORK(&w->work, once_deferred); w->key = key; schedule_work(&w->work); } static DEFINE_SPINLOCK(once_lock); bool __do_once_start(bool *done, unsigned long *flags) __acquires(once_lock) { spin_lock_irqsave(&once_lock, *flags); if (*done) { spin_unlock_irqrestore(&once_lock, *flags); /* Keep sparse happy by restoring an even lock count on * this lock. In case we return here, we don't call into * __do_once_done but return early in the DO_ONCE() macro. */ __acquire(once_lock); return false; } return true; } EXPORT_SYMBOL(__do_once_start); void __do_once_done(bool *done, struct static_key *once_key, unsigned long *flags) __releases(once_lock) { *done = true; spin_unlock_irqrestore(&once_lock, *flags); once_disable_jump(once_key); } EXPORT_SYMBOL(__do_once_done); <td> <a href='/cgit.cgi/linux/net-next.git/'>summary</a><a href='/cgit.cgi/linux/net-next.git/refs/'>refs</a><a class='active' href='/cgit.cgi/linux/net-next.git/log/tools'>log</a><a href='/cgit.cgi/linux/net-next.git/tree/tools'>tree</a><a href='/cgit.cgi/linux/net-next.git/commit/tools'>commit</a><a href='/cgit.cgi/linux/net-next.git/diff/tools'>diff</a></td><td class='form'><form class='right' method='get' action='/cgit.cgi/linux/net-next.git/log/tools'> <select name='qt'> <option value='grep'>log msg</option> <option value='author'>author</option> <option value='committer'>committer</option> <option value='range'>range</option> </select> <input class='txt' type='search' size='10' name='q' value=''/> <input type='submit' value='search'/> </form> </td></tr></table> <div class='path'>path: <a href='/cgit.cgi/linux/net-next.git/log/'>root</a>/<a href='/cgit.cgi/linux/net-next.git/log/tools'>tools</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/cgit.cgi/linux/net-next.git/log/tools?showmsg=1'>Expand</a>)</th><th class='left'>Author</th><th class='left'>Files</th><th class='left'>Lines</th></tr>