From patchwork Tue Feb 6 02:04:19 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Sakai X-Patchwork-Id: 13546526 X-Patchwork-Delegate: snitzer@redhat.com 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 779F056B63 for ; Tue, 6 Feb 2024 02:04:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707185069; cv=none; b=I225LNH2D9C7wo6Lsn1hSPY7lEPwPPvfhPPFJ4bG6MczE4iNr4a8rksFVcSL4robLUgpSdW1y4+GobFFAcmUzVKz4Em1NOBvILhNC/pAvnAuVR/EwXQzJVg+1EVm0OybfTrCe0iQSuRkiCCfeySoYDoQxYk6DPJrJpK4gIc2aMw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707185069; c=relaxed/simple; bh=QjCEwke2q8md+7XYXgP0M4hWqJ6rqzuJXuo/F2COq6Y=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Cpn8jEGxbq5DZrHATUixzQg4Dpwkz+5oL8/8TWRRJpeHB+R0VmtybqNKxDlftMl7xmRrmw5PInPo2wRESl9pXeypElvMlMyGsla8otit7GzS6Mqc39EbiReLZK60rCyA05F0mRlkG8bjxAHt5lpyRPWglzDd1WYZNIhzS9VNb4Y= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=Na7epnFr; arc=none smtp.client-ip=170.10.129.124 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="Na7epnFr" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1707185066; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=NsTg64+GPsxKmgqRI9XjEW4h5kvap/d+2pnLf1r3Y6A=; b=Na7epnFrMFZLylLNvA5KHwOamsmsgsxqIa2hzxkdvJeTpesCtDfULdi7nFuP2fckhjCGvM SoKvomq7GW9M+7S0J8TgS5CpnQcdIMUWOFtwMDIdlnOnlgCZpiyoH76geqH4CzVxdDnrNI yfAr6xm9TbXiUw/hAUrVzJqeFeZdO5Q= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-73-anSpZxPlOcOmy9gCheYTHw-1; Mon, 05 Feb 2024 21:04:23 -0500 X-MC-Unique: anSpZxPlOcOmy9gCheYTHw-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (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 A4F0884ACA2; Tue, 6 Feb 2024 02:04:22 +0000 (UTC) Received: from vdo-builder-msakai.permabit.com (vdo-builder-msakai.permabit.lab.eng.bos.redhat.com [10.0.103.170]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9FE37492BC7; Tue, 6 Feb 2024 02:04:22 +0000 (UTC) Received: by vdo-builder-msakai.permabit.com (Postfix, from userid 1138) id 9E759569FE; Mon, 5 Feb 2024 21:04:22 -0500 (EST) From: Matthew Sakai To: dm-devel@lists.linux.dev Cc: Mike Snitzer , Matthew Sakai Subject: [PATCH 4/7] dm vdo data-vio: silence sparse warnings about locking context imbalances Date: Mon, 5 Feb 2024 21:04:19 -0500 Message-ID: In-Reply-To: References: Precedence: bulk X-Mailing-List: dm-devel@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.9 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com From: Mike Snitzer Factor wait_permit() out from acquire_permit() so that the latter always holds the spinlock and the former always releases it. Otherwise sparse complains about locking context imbalances due to conditional spin_unlock in acquire_permit: warning: context imbalance in 'acquire_permit' - different lock contexts for basic block warning: context imbalance in 'vdo_launch_bio' - unexpected unlock Signed-off-by: Mike Snitzer Signed-off-by: Susan LeGendre-McGhee Signed-off-by: Matthew Sakai --- drivers/md/dm-vdo/data-vio.c | 35 +++++++++++++++++++++-------------- 1 file changed, 21 insertions(+), 14 deletions(-) diff --git a/drivers/md/dm-vdo/data-vio.c b/drivers/md/dm-vdo/data-vio.c index e0f1574ae112..d77adeb5006e 100644 --- a/drivers/md/dm-vdo/data-vio.c +++ b/drivers/md/dm-vdo/data-vio.c @@ -929,27 +929,30 @@ void free_data_vio_pool(struct data_vio_pool *pool) uds_free(pool); } -static bool acquire_permit(struct limiter *limiter, struct bio *bio) +static bool acquire_permit(struct limiter *limiter) { - if (limiter->busy >= limiter->limit) { - DEFINE_WAIT(wait); - - bio_list_add(&limiter->new_waiters, bio); - prepare_to_wait_exclusive(&limiter->blocked_threads, &wait, - TASK_UNINTERRUPTIBLE); - spin_unlock(&limiter->pool->lock); - io_schedule(); - finish_wait(&limiter->blocked_threads, &wait); + if (limiter->busy >= limiter->limit) return false; - } WRITE_ONCE(limiter->busy, limiter->busy + 1); if (limiter->max_busy < limiter->busy) WRITE_ONCE(limiter->max_busy, limiter->busy); - return true; } +static void wait_permit(struct limiter *limiter, struct bio *bio) + __releases(&limiter->pool->lock) +{ + DEFINE_WAIT(wait); + + bio_list_add(&limiter->new_waiters, bio); + prepare_to_wait_exclusive(&limiter->blocked_threads, &wait, + TASK_UNINTERRUPTIBLE); + spin_unlock(&limiter->pool->lock); + io_schedule(); + finish_wait(&limiter->blocked_threads, &wait); +} + /** * vdo_launch_bio() - Acquire a data_vio from the pool, assign the bio to it, and launch it. * @@ -965,11 +968,15 @@ void vdo_launch_bio(struct data_vio_pool *pool, struct bio *bio) bio->bi_private = (void *) jiffies; spin_lock(&pool->lock); if ((bio_op(bio) == REQ_OP_DISCARD) && - !acquire_permit(&pool->discard_limiter, bio)) + !acquire_permit(&pool->discard_limiter)) { + wait_permit(&pool->discard_limiter, bio); return; + } - if (!acquire_permit(&pool->limiter, bio)) + if (!acquire_permit(&pool->limiter)) { + wait_permit(&pool->limiter, bio); return; + } data_vio = get_available_data_vio(pool); spin_unlock(&pool->lock);