From 379af13b31fa8a36ad4abd59a5c511f25c5d4d42 Mon Sep 17 00:00:00 2001 From: Alexander Sverdlin Date: Mon, 12 Dec 2022 17:37:15 +0100 Subject: [PATCH] docs: locking: Discourage from calling disable_irq() in atomic Correct the example in the documentation so that disable_irq() is not being called in atomic context. disable_irq() calls sleeping synchronize_irq(), it's not allowed to call them in atomic context. Signed-off-by: Alexander Sverdlin Signed-off-by: Thomas Gleixner Reviewed-by: Manfred Spraul Cc: linux-doc@vger.kernel.org Link: https://lore.kernel.org/lkml/87k02wbs2n.ffs@tglx/ Link: https://lore.kernel.org/r/20221212163715.830315-1-alexander.sverdlin@siemens.com --- Documentation/kernel-hacking/locking.rst | 4 ++-- Documentation/translations/it_IT/kernel-hacking/locking.rst | 4 ++-- 2 files changed, 4 insertions(+), 4 deletions(-) diff --git a/Documentation/kernel-hacking/locking.rst b/Documentation/kernel-hacking/locking.rst index c756786e17ae..dff0646a717b 100644 --- a/Documentation/kernel-hacking/locking.rst +++ b/Documentation/kernel-hacking/locking.rst @@ -1277,11 +1277,11 @@ Manfred Spraul points out that you can still do this, even if the data is very occasionally accessed in user context or softirqs/tasklets. The irq handler doesn't use a lock, and all other accesses are done as so:: - spin_lock(&lock); + mutex_lock(&lock); disable_irq(irq); ... enable_irq(irq); - spin_unlock(&lock); + mutex_unlock(&lock); The disable_irq() prevents the irq handler from running (and waits for it to finish if it's currently running on other CPUs). diff --git a/Documentation/translations/it_IT/kernel-hacking/locking.rst b/Documentation/translations/it_IT/kernel-hacking/locking.rst index b8ecf41273c5..05d362b16bf0 100644 --- a/Documentation/translations/it_IT/kernel-hacking/locking.rst +++ b/Documentation/translations/it_IT/kernel-hacking/locking.rst @@ -1307,11 +1307,11 @@ se i dati vengono occasionalmente utilizzati da un contesto utente o da un'interruzione software. Il gestore d'interruzione non utilizza alcun *lock*, e tutti gli altri accessi verranno fatti così:: - spin_lock(&lock); + mutex_lock(&lock); disable_irq(irq); ... enable_irq(irq); - spin_unlock(&lock); + mutex_unlock(&lock); La funzione disable_irq() impedisce al gestore d'interruzioni d'essere eseguito (e aspetta che finisca nel caso fosse in esecuzione su