From patchwork Sun Apr 10 22:39:40 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bob Pearson X-Patchwork-Id: 12808332 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5AF11C4332F for ; Sun, 10 Apr 2022 22:44:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232193AbiDJWqU (ORCPT ); Sun, 10 Apr 2022 18:46:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38542 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232158AbiDJWqO (ORCPT ); Sun, 10 Apr 2022 18:46:14 -0400 Received: from mail-oi1-x233.google.com (mail-oi1-x233.google.com [IPv6:2607:f8b0:4864:20::233]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EB1AF18E; Sun, 10 Apr 2022 15:44:01 -0700 (PDT) Received: by mail-oi1-x233.google.com with SMTP id e189so14220414oia.8; Sun, 10 Apr 2022 15:44:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=hpXBKems3UG+wFxv0QCe5MNRbLOMx85cf7BfRRO6zmU=; b=LHcqPy2pCPxk0g7PcqDQbA5+VjLEZ388wIecksOL4Rs8mquDlHheaBsjsei2K1xPjj IW0S2i6DdjoKMkliXqOEmwSd9w2GE8GzhVqqhFkYlg9mU0O/eQU5ikbJhEYAcemZ2cg0 X0QLfKATIX69kDDp9N9eiHgjVfYro7smDr7xJobD+IH896POevvNCJuO9eCMJb9sz2V7 uWy+O/cHJSnf4MwbsEe2gIMO3XLR9ZQqzl1d7YHa25mWg/7yRzDMkJR8HkOgxJCSWpyU i3aZkrLhcPQgtCRrYefIsW65uZXovCbYCWZeaqwhlWOqnmPF5vKAPKkWDtdXIzzqVik+ 1ctA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=hpXBKems3UG+wFxv0QCe5MNRbLOMx85cf7BfRRO6zmU=; b=LcQF2xRcSokSvSbFq6N594wDoUWkdiYQKB80iJN5Tu8rF2jOBbNVm0TqRg3OL5iGwJ bQLgStrwiDv8M6O6wqfWcBKpOSvRYvrKSYqawXY/PfpjXV+a2lSxp2jN4rcbIPjEOYEr 5s4GKi1SMDV2bROfEl14Hb+p4eAnlGVXq/Tw0Uq4YzrRkB6QtMzrLVKdT90Mctx+AuJM 7DP/wBekTe7KP9EJTDR9yYpNt2YWnNiCXr/631zHlcu0jXZNnwuneCCsjOJXLa7YGOfD 7ajgMhKhNHZwFZkUKwc64olaZl5r/CbdRz6jisxffFObVROpvEzPc7SAHpH3HBzJRoNO ofxA== X-Gm-Message-State: AOAM530B8sTILw+Om32ifCciHalPgXO8DKQFW4TJg9FRtcAgP2mQM630 DwVdtFKPF71k3iO1FBSz9FE= X-Google-Smtp-Source: ABdhPJy3eekkjOw+1iVq4Y0fJoVCg3ivdiOox0nSgj0fSybVf6+AZOkC2Bvx2a7V1AbGu4dUXj5/xQ== X-Received: by 2002:aca:705:0:b0:2d9:6bb6:5b0 with SMTP id 5-20020aca0705000000b002d96bb605b0mr4106169oih.11.1649630641165; Sun, 10 Apr 2022 15:44:01 -0700 (PDT) Received: from ubuntu-21.tx.rr.com (2603-8081-140c-1a00-dc1d-a6ff-2878-e7c1.res6.spectrum.com. [2603:8081:140c:1a00:dc1d:a6ff:2878:e7c1]) by smtp.googlemail.com with ESMTPSA id 60-20020a9d0642000000b005b22a82458csm11610304otn.55.2022.04.10.15.44.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 10 Apr 2022 15:44:00 -0700 (PDT) From: Bob Pearson To: bvanassche@acm.org, jgg@nvidia.com, zyjzyj2000@gmail.com, linux-rdma@vger.kernel.org, linux-scsi@vger.kernel.org, yi.zhang@redhat.com Cc: Bob Pearson Subject: [PATCH for-next] RDMA/rxe: Fix "Replace red-black trees by xarrays" Date: Sun, 10 Apr 2022 17:39:40 -0500 Message-Id: <20220410223939.3769-1-rpearsonhpe@gmail.com> X-Mailer: git-send-email 2.32.0 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org The referenced commit causes lockdep warnings by using the default spin_lock in xa_alloc_cyclic and xa_erase which include calls to xa_lock()/xa_unlock() while at the same time explicitly calling xa_lock_irqsave() in rxe_pool_get_index(). The latter is required to handle some object lookups correctly. The immediate fix is to explicitly use xa_lock_irqsave() everywhere. This commit replaces xa_alloc_cyclic() by __xa_alloc_cyclic() and xa_erase() by __xa_erase() and explicitly lock these calls with xa_lock_irqsave(). This commit will be reverted later when the read side operations in rxe_pool.c will be converted to rcu_read_locks which will not require locking the write side operations with irqsave locks. This commit fixes the "WARNING: Inconsistent lock state" bug in blktests. The recent revert patch from Bart fixes the other bug in blktests with very long delays. Fixes: 3225717f6dfa ("RDMA/rxe: Replace red-black trees by carrays") Signed-off-by: Bob Pearson --- drivers/infiniband/sw/rxe/rxe_pool.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/drivers/infiniband/sw/rxe/rxe_pool.c b/drivers/infiniband/sw/rxe/rxe_pool.c index 87066d04ed18..440f96af213b 100644 --- a/drivers/infiniband/sw/rxe/rxe_pool.c +++ b/drivers/infiniband/sw/rxe/rxe_pool.c @@ -118,7 +118,9 @@ void rxe_pool_cleanup(struct rxe_pool *pool) void *rxe_alloc(struct rxe_pool *pool) { + struct xarray *xa = &pool->xa; struct rxe_pool_elem *elem; + unsigned long flags; void *obj; int err; @@ -138,8 +140,10 @@ void *rxe_alloc(struct rxe_pool *pool) elem->obj = obj; kref_init(&elem->ref_cnt); - err = xa_alloc_cyclic(&pool->xa, &elem->index, elem, pool->limit, + xa_lock_irqsave(xa, flags); + err = __xa_alloc_cyclic(&pool->xa, &elem->index, elem, pool->limit, &pool->next, GFP_KERNEL); + xa_unlock_irqrestore(xa, flags); if (err) goto err_free; @@ -154,6 +158,8 @@ void *rxe_alloc(struct rxe_pool *pool) int __rxe_add_to_pool(struct rxe_pool *pool, struct rxe_pool_elem *elem) { + struct xarray *xa = &pool->xa; + unsigned long flags; int err; if (WARN_ON(pool->flags & RXE_POOL_ALLOC)) @@ -166,8 +172,10 @@ int __rxe_add_to_pool(struct rxe_pool *pool, struct rxe_pool_elem *elem) elem->obj = (u8 *)elem - pool->elem_offset; kref_init(&elem->ref_cnt); - err = xa_alloc_cyclic(&pool->xa, &elem->index, elem, pool->limit, + xa_lock_irqsave(xa, flags); + err = __xa_alloc_cyclic(&pool->xa, &elem->index, elem, pool->limit, &pool->next, GFP_KERNEL); + xa_unlock_irqrestore(xa, flags); if (err) goto err_cnt; @@ -200,8 +208,12 @@ static void rxe_elem_release(struct kref *kref) { struct rxe_pool_elem *elem = container_of(kref, typeof(*elem), ref_cnt); struct rxe_pool *pool = elem->pool; + struct xarray *xa = &pool->xa; + unsigned long flags; - xa_erase(&pool->xa, elem->index); + xa_lock_irqsave(xa, flags); + __xa_erase(&pool->xa, elem->index); + xa_unlock_irqrestore(xa, flags); if (pool->cleanup) pool->cleanup(elem);