From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A2AB2C433DB for ; Sun, 7 Mar 2021 15:11:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5F1FE64FC2 for ; Sun, 7 Mar 2021 15:11:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229753AbhCGPKy (ORCPT ); Sun, 7 Mar 2021 10:10:54 -0500 Received: from mail.kernel.org ([198.145.29.99]:57680 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230175AbhCGPKk (ORCPT ); Sun, 7 Mar 2021 10:10:40 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id AB503650FA; Sun, 7 Mar 2021 15:10:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1615129840; bh=gjcr8uLOxfyRxbBrvhEXh9ZsrDNkpRLLhlCdgG4ysAI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=k71Eevojui7UKApxi9zWj2gZ5RvJKtszBLoCCBEVYxzUuM0u0ISIMN9hEzHCgwUjm dQuFZWJ3eDYsx95GOfuN7lGGC+CAHROPF/z+1ysAK8F3BLQQZz9SA4wAcGOSTDahrQ RGUBMujYQFI56YsHkmulADC/y9kWl6EPNttTLNo4= Date: Sun, 7 Mar 2021 16:10:37 +0100 From: Greg KH To: Jeffle Xu Cc: sashal@kernel.org, stable@vger.kernel.org, snitzer@redhat.com Subject: Re: [PATCH 4.14.y 1/4] dm table: fix iterate_devices based device capability checks Message-ID: References: <16146062492354@kroah.com> <20210305065250.70340-1-jefflexu@linux.alibaba.com> <20210305065250.70340-2-jefflexu@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210305065250.70340-2-jefflexu@linux.alibaba.com> Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Fri, Mar 05, 2021 at 02:52:47PM +0800, Jeffle Xu wrote: > commit a4c8dd9c2d0987cf542a2a0c42684c9c6d78a04e upstream. > > According to the definition of dm_iterate_devices_fn: > * This function must iterate through each section of device used by the > * target until it encounters a non-zero return code, which it then returns. > * Returns zero if no callout returned non-zero. > > For some target type (e.g. dm-stripe), one call of iterate_devices() may > iterate multiple underlying devices internally, in which case a non-zero > return code returned by iterate_devices_callout_fn will stop the iteration > in advance. No iterate_devices_callout_fn should return non-zero unless > device iteration should stop. > > Rename dm_table_requires_stable_pages() to dm_table_any_dev_attr() and > elevate it for reuse to stop iterating (and return non-zero) on the > first device that causes iterate_devices_callout_fn to return non-zero. > Use dm_table_any_dev_attr() to properly iterate through devices. > > Rename device_is_nonrot() to device_is_rotational() and invert logic > accordingly to fix improper disposition. > > Fixes: c3c4555edd10 ("dm table: clear add_random unless all devices have it set") > Fixes: 4693c9668fdc ("dm table: propagate non rotational flag") > Cc: stable@vger.kernel.org > Signed-off-by: Jeffle Xu > Signed-off-by: Mike Snitzer > --- > drivers/md/dm-table.c | 97 +++++++++++++++++++++++-------------------- > 1 file changed, 51 insertions(+), 46 deletions(-) > > diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c > index c855ab2feb18..6fe720e2c6ba 100644 > --- a/drivers/md/dm-table.c > +++ b/drivers/md/dm-table.c > @@ -1351,6 +1351,46 @@ struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector) > return &t->targets[(KEYS_PER_NODE * n) + k]; > } > > +/* > + * type->iterate_devices() should be called when the sanity check needs to > + * iterate and check all underlying data devices. iterate_devices() will > + * iterate all underlying data devices until it encounters a non-zero return > + * code, returned by whether the input iterate_devices_callout_fn, or > + * iterate_devices() itself internally. > + * > + * For some target type (e.g. dm-stripe), one call of iterate_devices() may > + * iterate multiple underlying devices internally, in which case a non-zero > + * return code returned by iterate_devices_callout_fn will stop the iteration > + * in advance. > + * > + * Cases requiring _any_ underlying device supporting some kind of attribute, > + * should use the iteration structure like dm_table_any_dev_attr(), or call > + * it directly. @func should handle semantics of positive examples, e.g. > + * capable of something. > + * > + * Cases requiring _all_ underlying devices supporting some kind of attribute, > + * should use the iteration structure like dm_table_supports_nowait() or > + * dm_table_supports_discards(). Or introduce dm_table_all_devs_attr() that > + * uses an @anti_func that handle semantics of counter examples, e.g. not > + * capable of something. So: return !dm_table_any_dev_attr(t, anti_func); > + */ > +static bool dm_table_any_dev_attr(struct dm_table *t, > + iterate_devices_callout_fn func) > +{ > + struct dm_target *ti; > + unsigned int i; > + > + for (i = 0; i < dm_table_get_num_targets(t); i++) { > + ti = dm_table_get_target(t, i); > + > + if (ti->type->iterate_devices && > + ti->type->iterate_devices(ti, func, NULL)) > + return true; > + } > + > + return false; > +} > + > static int count_device(struct dm_target *ti, struct dm_dev *dev, > sector_t start, sector_t len, void *data) > { > @@ -1667,12 +1707,12 @@ static int dm_table_supports_dax_write_cache(struct dm_table *t) > return false; > } > > -static int device_is_nonrot(struct dm_target *ti, struct dm_dev *dev, > - sector_t start, sector_t len, void *data) > +static int device_is_rotational(struct dm_target *ti, struct dm_dev *dev, > + sector_t start, sector_t len, void *data) > { > struct request_queue *q = bdev_get_queue(dev->bdev); > > - return q && blk_queue_nonrot(q); > + return q && !blk_queue_nonrot(q); > } > > static int device_is_not_random(struct dm_target *ti, struct dm_dev *dev, > @@ -1691,23 +1731,6 @@ static int queue_supports_sg_merge(struct dm_target *ti, struct dm_dev *dev, > return q && !test_bit(QUEUE_FLAG_NO_SG_MERGE, &q->queue_flags); > } > > -static bool dm_table_all_devices_attribute(struct dm_table *t, > - iterate_devices_callout_fn func) > -{ > - struct dm_target *ti; > - unsigned i; > - > - for (i = 0; i < dm_table_get_num_targets(t); i++) { > - ti = dm_table_get_target(t, i); > - > - if (!ti->type->iterate_devices || > - !ti->type->iterate_devices(ti, func, NULL)) > - return false; > - } > - > - return true; > -} > - > static int device_not_write_same_capable(struct dm_target *ti, struct dm_dev *dev, > sector_t start, sector_t len, void *data) > { > @@ -1804,27 +1827,6 @@ static int device_requires_stable_pages(struct dm_target *ti, > return q && bdi_cap_stable_pages_required(q->backing_dev_info); > } > > -/* > - * If any underlying device requires stable pages, a table must require > - * them as well. Only targets that support iterate_devices are considered: > - * don't want error, zero, etc to require stable pages. > - */ > -static bool dm_table_requires_stable_pages(struct dm_table *t) > -{ > - struct dm_target *ti; > - unsigned i; > - > - for (i = 0; i < dm_table_get_num_targets(t); i++) { > - ti = dm_table_get_target(t, i); > - > - if (ti->type->iterate_devices && > - ti->type->iterate_devices(ti, device_requires_stable_pages, NULL)) > - return true; > - } > - > - return false; > -} > - > void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q, > struct queue_limits *limits) > { > @@ -1856,10 +1858,10 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q, > dax_write_cache(t->md->dax_dev, true); > > /* Ensure that all underlying devices are non-rotational. */ > - if (dm_table_all_devices_attribute(t, device_is_nonrot)) > - queue_flag_set_unlocked(QUEUE_FLAG_NONROT, q); > - else > + if (dm_table_any_dev_attr(t, device_is_rotational)) > queue_flag_clear_unlocked(QUEUE_FLAG_NONROT, q); > + else > + queue_flag_set_unlocked(QUEUE_FLAG_NONROT, q); > > if (!dm_table_supports_write_same(t)) > q->limits.max_write_same_sectors = 0; > @@ -1876,8 +1878,11 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q, > /* > * Some devices don't use blk_integrity but still want stable pages > * because they do their own checksumming. > + * If any underlying device requires stable pages, a table must require > + * them as well. Only targets that support iterate_devices are considered: > + * don't want error, zero, etc to require stable pages. > */ > - if (dm_table_requires_stable_pages(t)) > + if (dm_table_any_dev_attr(t, device_requires_stable_pages)) > q->backing_dev_info->capabilities |= BDI_CAP_STABLE_WRITES; > else > q->backing_dev_info->capabilities &= ~BDI_CAP_STABLE_WRITES; > @@ -1888,7 +1893,7 @@ void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q, > * Clear QUEUE_FLAG_ADD_RANDOM if any underlying device does not > * have it set. > */ > - if (blk_queue_add_random(q) && dm_table_all_devices_attribute(t, device_is_not_random)) > + if (blk_queue_add_random(q) && dm_table_any_dev_attr(t, device_is_not_random)) > queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, q); > > /* > -- > 2.27.0 > Breaks the build :(