From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 D7C2E3A1CD for ; Mon, 6 May 2024 00:59:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714957162; cv=none; b=D1uNRP76VNgzrL+f00VydPQr9O0IDzoLjzMMsbmHolIhkRaKgPr6Ex1UKxFj3lR34ClnKTJXKMTklpPbWgdCKdYjRm12Ut7oLkKza48f7VKfRXPlag0FgVQEwIXa/UQ8oGjdJcthFusn7RUkHQXKYohXJbSpeFLkAm+ybecI+Q4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714957162; c=relaxed/simple; bh=NykD8XPmT83khMH7WCjpU99SIt1wNPa6IPQcL5vFMwI=; h=Date:To:From:Subject:Message-Id; b=bougicOFOnS//ccnuRF72YLn4JhzeHc8TsMn0R64OUFKiZREjigBJUayL6iF4FV9J24E8uIcHsDDHbctdBAqUG39CxEHptFHoU7EzpgCg1LsM6Ltl6fwJAJN1Vupce1XD6mO+mdJK/LJkT+8RfUHL1WoRJ7Zvrf02R4wAlxdlKQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=Gid0d3CT; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="Gid0d3CT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AE911C113CC; Mon, 6 May 2024 00:59:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1714957162; bh=NykD8XPmT83khMH7WCjpU99SIt1wNPa6IPQcL5vFMwI=; h=Date:To:From:Subject:From; b=Gid0d3CTpzW7jCvDHUezbTu7ytyrC4Xjx/TsMzyMROjfuNnSw/DWO4XYSBYoj7i4x y82okMWqpow35Cl+cjylm1R1cKoRlOrvKafvwZND45bPjAC79D5h1EYbnRwhluLGoC xBWgLorQbdpKJsyZ5Cahf5tiEz420tc3Yndo1orc= Date: Sun, 05 May 2024 17:59:22 -0700 To: mm-commits@vger.kernel.org,dave.jiang@intel.com,dan.j.williams@intel.com,alison.schofield@intel.com,vishal.l.verma@intel.com,akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-stable] dax-busc-fix-locking-for-unregister_dax_dev-unregister_dax_mapping-paths.patch removed from -mm tree Message-Id: <20240506005922.AE911C113CC@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: dax/bus.c: fix locking for unregister_dax_dev / unregister_dax_mapping paths has been removed from the -mm tree. Its filename was dax-busc-fix-locking-for-unregister_dax_dev-unregister_dax_mapping-paths.patch This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Vishal Verma Subject: dax/bus.c: fix locking for unregister_dax_dev / unregister_dax_mapping paths Date: Tue, 30 Apr 2024 11:44:24 -0600 Commit c05ae9d85b47 ("dax/bus.c: replace driver-core lock usage by a local rwsem") aimed to undo device_lock() abuses for protecting changes to dax-driver internal data-structures like the dax_region resource tree to device-dax-instance range structures. However, the device_lock() was legitimately enforcing that devices to be deleted were not current actively attached to any driver nor assigned any capacity from the region. As a result of the device_lock restoration in delete_store(), the conditional locking in unregister_dev_dax() and unregister_dax_mapping() can be removed. Link: https://lkml.kernel.org/r/20240430-vv-dax_abi_fixes-v3-2-e3dcd755774c@intel.com Fixes: c05ae9d85b47 ("dax/bus.c: replace driver-core lock usage by a local rwsem") Signed-off-by: Vishal Verma Reported-by: Dan Williams Reviewed-by: Dan Williams Cc: Alison Schofield Cc: Dave Jiang Signed-off-by: Andrew Morton --- drivers/dax/bus.c | 42 ++++++++---------------------------------- 1 file changed, 8 insertions(+), 34 deletions(-) --- a/drivers/dax/bus.c~dax-busc-fix-locking-for-unregister_dax_dev-unregister_dax_mapping-paths +++ a/drivers/dax/bus.c @@ -465,26 +465,17 @@ static void free_dev_dax_ranges(struct d trim_dev_dax_range(dev_dax); } -static void __unregister_dev_dax(void *dev) +static void unregister_dev_dax(void *dev) { struct dev_dax *dev_dax = to_dev_dax(dev); dev_dbg(dev, "%s\n", __func__); + down_write(&dax_region_rwsem); kill_dev_dax(dev_dax); device_del(dev); free_dev_dax_ranges(dev_dax); put_device(dev); -} - -static void unregister_dev_dax(void *dev) -{ - if (rwsem_is_locked(&dax_region_rwsem)) - return __unregister_dev_dax(dev); - - if (WARN_ON_ONCE(down_write_killable(&dax_region_rwsem) != 0)) - return; - __unregister_dev_dax(dev); up_write(&dax_region_rwsem); } @@ -560,15 +551,10 @@ static ssize_t delete_store(struct devic if (!victim) return -ENXIO; - rc = down_write_killable(&dax_region_rwsem); - if (rc) - return rc; - rc = down_write_killable(&dax_dev_rwsem); - if (rc) { - up_write(&dax_region_rwsem); - return rc; - } + device_lock(dev); + device_lock(victim); dev_dax = to_dev_dax(victim); + down_write(&dax_dev_rwsem); if (victim->driver || dev_dax_size(dev_dax)) rc = -EBUSY; else { @@ -589,11 +575,12 @@ static ssize_t delete_store(struct devic rc = -EBUSY; } up_write(&dax_dev_rwsem); + device_unlock(victim); /* won the race to invalidate the device, clean it up */ if (do_del) devm_release_action(dev, unregister_dev_dax, victim); - up_write(&dax_region_rwsem); + device_unlock(dev); put_device(victim); return rc; @@ -705,7 +692,7 @@ static void dax_mapping_release(struct d put_device(parent); } -static void __unregister_dax_mapping(void *data) +static void unregister_dax_mapping(void *data) { struct device *dev = data; struct dax_mapping *mapping = to_dax_mapping(dev); @@ -713,25 +700,12 @@ static void __unregister_dax_mapping(voi dev_dbg(dev, "%s\n", __func__); - lockdep_assert_held_write(&dax_region_rwsem); - dev_dax->ranges[mapping->range_id].mapping = NULL; mapping->range_id = -1; device_unregister(dev); } -static void unregister_dax_mapping(void *data) -{ - if (rwsem_is_locked(&dax_region_rwsem)) - return __unregister_dax_mapping(data); - - if (WARN_ON_ONCE(down_write_killable(&dax_region_rwsem) != 0)) - return; - __unregister_dax_mapping(data); - up_write(&dax_region_rwsem); -} - static struct dev_dax_range *get_dax_range(struct device *dev) { struct dax_mapping *mapping = to_dax_mapping(dev); _ Patches currently in -mm which might be from vishal.l.verma@intel.com are