From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 517521C69B for ; Fri, 3 Nov 2023 16:16:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="E9raVbZi" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1699028201; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=tGwXPfRgzPSC1/7v7/xvW9BOx29g/brNKkSt4SGOuac=; b=E9raVbZirm9eCJOX5qgA4UJHScidBS07VBGEVh/hdKUS1XEuYN57U7Uv6B0IiZnBFWrFtV YkOzgZvtam4ISEMNgf3FmnPhmmt1Z2SPmImc4Wy97jGf1x/cGH2YSENEXJ+PKkWgaRnlb6 zbzAjZG/7s2TEJfLUOkXGfj8Hhpu2x8= Received: from mimecast-mx02.redhat.com (mx-ext.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-687-0WUFZsn1MwqGhvhsr2N9QA-1; Fri, 03 Nov 2023 12:16:36 -0400 X-MC-Unique: 0WUFZsn1MwqGhvhsr2N9QA-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 758883806710; Fri, 3 Nov 2023 16:16:36 +0000 (UTC) Received: from fs-i40c-03.fs.lab.eng.bos.redhat.com (fs-i40c-03.fast.rdu2.eng.redhat.com [10.6.23.54]) by smtp.corp.redhat.com (Postfix) with ESMTP id 511B71121308; Fri, 3 Nov 2023 16:16:36 +0000 (UTC) From: Alexander Aring To: will@kernel.org Cc: gfs2@lists.linux.dev, aahringo@redhat.com, peterz@infradead.org, boqun.feng@gmail.com, mark.rutland@arm.com, linux-kernel@vger.kernel.org Subject: [RFC 1/2] refcount: introduce generic lockptr funcs Date: Fri, 3 Nov 2023 12:16:34 -0400 Message-Id: <20231103161635.1902667-1-aahringo@redhat.com> Precedence: bulk X-Mailing-List: gfs2@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.3 This patch introduce lockptr refcount operations. Currently refcount has a lot of refcount_dec_and_lock() functionality for most common used locktype. Those functions look mostly all the same and is duplicated inside the refcount implementation. Instead of introducing a new whole refcount_dec_and_lock() functionality e.g. for rwlock_t and their _bh variants this patch will introduce lockptr. A lockptr is just a void * and refers to the actual locking instance that can even be an own locking type. Over the passed callbacks for lock and unlock operations the void *lockptr becomes to the real thing by casting it and do the locktype specific lock operation. Signed-off-by: Alexander Aring --- include/linux/refcount.h | 15 +++++++ lib/refcount.c | 92 ++++++++++++++++++++++++++++------------ 2 files changed, 80 insertions(+), 27 deletions(-) diff --git a/include/linux/refcount.h b/include/linux/refcount.h index a62fcca97486..7b1fb85212cc 100644 --- a/include/linux/refcount.h +++ b/include/linux/refcount.h @@ -366,4 +366,19 @@ extern __must_check bool refcount_dec_and_lock(refcount_t *r, spinlock_t *lock) extern __must_check bool refcount_dec_and_lock_irqsave(refcount_t *r, spinlock_t *lock, unsigned long *flags) __cond_acquires(lock); +extern bool refcount_dec_and_lockptr(refcount_t *r, void (*lock)(void *lockptr), + void (*unlock)(void *lockptr), void *lockptr) __cond_acquires(lockptr); + +extern void lockptr_mutex_lock(void *lockptr) __acquires(lockptr); +extern void lockptr_mutex_unlock(void *lockptr) __releases(lockptr); +extern void lockptr_spin_lock(void *lockptr) __acquires(lockptr); +extern void lockptr_spin_unlock(void *lockptr) __releases(lockptr); + +struct lockptr_irqsave_data { + void *lockptr; + unsigned long *flags; +}; +extern void lockptr_irqsave(void *lockptr) __acquires(lockptr); +extern void lockptr_irqsave(void *lockptr) __releases(lockptr); + #endif /* _LINUX_REFCOUNT_H */ diff --git a/lib/refcount.c b/lib/refcount.c index a207a8f22b3c..e28678f0f473 100644 --- a/lib/refcount.c +++ b/lib/refcount.c @@ -94,6 +94,34 @@ bool refcount_dec_not_one(refcount_t *r) } EXPORT_SYMBOL(refcount_dec_not_one); +bool refcount_dec_and_lockptr(refcount_t *r, void (*lock)(void *lockptr), + void (*unlock)(void *lockptr), void *lockptr) +{ + if (refcount_dec_not_one(r)) + return false; + + lock(lockptr); + if (!refcount_dec_and_test(r)) { + unlock(lockptr); + return false; + } + + return true; +} +EXPORT_SYMBOL(refcount_dec_and_lockptr); + +void lockptr_mutex_lock(void *lockptr) +{ + mutex_lock(lockptr); +} +EXPORT_SYMBOL(lockptr_mutex_lock); + +void lockptr_mutex_unlock(void *lockptr) +{ + mutex_unlock(lockptr); +} +EXPORT_SYMBOL(lockptr_mutex_unlock); + /** * refcount_dec_and_mutex_lock - return holding mutex if able to decrement * refcount to 0 @@ -112,18 +140,22 @@ EXPORT_SYMBOL(refcount_dec_not_one); */ bool refcount_dec_and_mutex_lock(refcount_t *r, struct mutex *lock) { - if (refcount_dec_not_one(r)) - return false; + return refcount_dec_and_lockptr(r, lockptr_mutex_lock, + lockptr_mutex_unlock, lock); +} +EXPORT_SYMBOL(refcount_dec_and_mutex_lock); - mutex_lock(lock); - if (!refcount_dec_and_test(r)) { - mutex_unlock(lock); - return false; - } +void lockptr_spin_lock(void *lockptr) +{ + spin_lock(lockptr); +} +EXPORT_SYMBOL(lockptr_spin_lock); - return true; +void lockptr_spin_unlock(void *lockptr) +{ + spin_unlock(lockptr); } -EXPORT_SYMBOL(refcount_dec_and_mutex_lock); +EXPORT_SYMBOL(lockptr_spin_unlock); /** * refcount_dec_and_lock - return holding spinlock if able to decrement @@ -143,18 +175,26 @@ EXPORT_SYMBOL(refcount_dec_and_mutex_lock); */ bool refcount_dec_and_lock(refcount_t *r, spinlock_t *lock) { - if (refcount_dec_not_one(r)) - return false; + return refcount_dec_and_lockptr(r, lockptr_spin_lock, + lockptr_spin_unlock, lock); +} +EXPORT_SYMBOL(refcount_dec_and_lock); - spin_lock(lock); - if (!refcount_dec_and_test(r)) { - spin_unlock(lock); - return false; - } +void lockptr_lock_irqsave(void *lockptr) +{ + struct lockptr_irqsave_data *d = lockptr; - return true; + spin_lock_irqsave(d->lockptr, *d->flags); } -EXPORT_SYMBOL(refcount_dec_and_lock); +EXPORT_SYMBOL(lockptr_lock_irqsave); + +void lockptr_unlock_irqsave(void *lockptr) +{ + struct lockptr_irqsave_data *d = lockptr; + + spin_unlock_irqrestore(d->lockptr, *d->flags); +} +EXPORT_SYMBOL(lockptr_unlock_irqsave); /** * refcount_dec_and_lock_irqsave - return holding spinlock with disabled @@ -172,15 +212,13 @@ EXPORT_SYMBOL(refcount_dec_and_lock); bool refcount_dec_and_lock_irqsave(refcount_t *r, spinlock_t *lock, unsigned long *flags) { - if (refcount_dec_not_one(r)) - return false; + struct lockptr_irqsave_data d = { + .lockptr = lock, + .flags = flags, + }; - spin_lock_irqsave(lock, *flags); - if (!refcount_dec_and_test(r)) { - spin_unlock_irqrestore(lock, *flags); - return false; - } - - return true; + return refcount_dec_and_lockptr(r, lockptr_lock_irqsave, + lockptr_unlock_irqsave, &d); } EXPORT_SYMBOL(refcount_dec_and_lock_irqsave); + -- 2.39.3