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[68.160.141.91]) by smtp.gmail.com with ESMTPSA id l22-20020ac87256000000b0042bf0b37b5csm1974371qtp.28.2024.02.03.09.58.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 03 Feb 2024 09:58:49 -0800 (PST) Date: Sat, 3 Feb 2024 12:58:48 -0500 From: Mike Snitzer To: Damien Le Moal Cc: linux-block@vger.kernel.org, Jens Axboe , linux-scsi@vger.kernel.org, "Martin K . Petersen" , dm-devel@lists.linux.dev, Christoph Hellwig Subject: Re: [PATCH 10/26] dm: Use the block layer zone append emulation Message-ID: References: <20240202073104.2418230-1-dlemoal@kernel.org> <20240202073104.2418230-11-dlemoal@kernel.org> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240202073104.2418230-11-dlemoal@kernel.org> On Fri, Feb 02 2024 at 2:30P -0500, Damien Le Moal wrote: > For targets requiring zone append operation emulation with regular > writes (e.g. dm-crypt), we can use the block layer emulation provided by > zone write plugging. Remove DM implemented zone append emulation and > enable the block layer one. > > This is done by setting the max_zone_append_sectors limit of the > mapped device queue to 0 for mapped devices that have a target table > that cannot support native zone append operations. These includes > mixed zoned and non-zoned targets, or targets that explicitly requested > emulation of zone append (e.g. dm-crypt). For these mapped devices, the > new field emulate_zone_append is set to true. dm_split_and_process_bio() > is modified to call blk_zone_write_plug_bio() for such device to let the > block layer transform zone append operations into regular writes. This > is done after ensuring that the submitted BIO is split if it straddles > zone boundaries. > > dm_revalidate_zones() is also modified to use the block layer provided > function blk_revalidate_disk_zones() so that all zone resources needed > for zone append emulation are allocated and initialized by the block > layer without DM core needing to do anything. Since the device table is > not yet live when dm_revalidate_zones() is executed, enabling the use of > blk_revalidate_disk_zones() requires adding a pointer to the device > table in struct mapped_device. This avoids errors in > dm_blk_report_zones() trying to get the table with dm_get_live_table(). > The mapped device table pointer is set to the table passed as argument > to dm_revalidate_zones() before calling blk_revalidate_disk_zones() and > reset to NULL after this function returns to restore the live table > handling for user call of report zones. > > All the code related to zone append emulation is removed from > dm-zone.c. This leads to simplifications of the functions __map_bio() > and dm_zone_endio(). This later function now only needs to deal with > completions of real zone append operations for targets that support it. > > Signed-off-by: Damien Le Moal Love the overall improvement to the DM core code and the broader block layer by switching to this bio-based ZWP approach. Reviewed-by: Mike Snitzer But one incremental suggestion inlined below. > --- > drivers/md/dm-core.h | 11 +- > drivers/md/dm-zone.c | 470 ++++--------------------------------------- > drivers/md/dm.c | 44 ++-- > drivers/md/dm.h | 7 - > 4 files changed, 68 insertions(+), 464 deletions(-) > > diff --git a/drivers/md/dm.c b/drivers/md/dm.c > index 8dcabf84d866..92ce3b2eb4ae 100644 > --- a/drivers/md/dm.c > +++ b/drivers/md/dm.c > @@ -1419,25 +1419,12 @@ static void __map_bio(struct bio *clone) > down(&md->swap_bios_semaphore); > } > > - if (static_branch_unlikely(&zoned_enabled)) { > - /* > - * Check if the IO needs a special mapping due to zone append > - * emulation on zoned target. In this case, dm_zone_map_bio() > - * calls the target map operation. > - */ > - if (unlikely(dm_emulate_zone_append(md))) > - r = dm_zone_map_bio(tio); > - else > - goto do_map; > - } else { > -do_map: > - if (likely(ti->type->map == linear_map)) > - r = linear_map(ti, clone); > - else if (ti->type->map == stripe_map) > - r = stripe_map(ti, clone); > - else > - r = ti->type->map(ti, clone); > - } > + if (likely(ti->type->map == linear_map)) > + r = linear_map(ti, clone); > + else if (ti->type->map == stripe_map) > + r = stripe_map(ti, clone); > + else > + r = ti->type->map(ti, clone); > > switch (r) { > case DM_MAPIO_SUBMITTED: > @@ -1774,19 +1761,33 @@ static void dm_split_and_process_bio(struct mapped_device *md, > struct clone_info ci; > struct dm_io *io; > blk_status_t error = BLK_STS_OK; > - bool is_abnormal; > + bool is_abnormal, need_split; > > is_abnormal = is_abnormal_io(bio); > - if (unlikely(is_abnormal)) { > + if (likely(!md->emulate_zone_append)) > + need_split = is_abnormal; > + else > + need_split = is_abnormal || bio_straddle_zones(bio); > + if (unlikely(need_split)) { > /* > * Use bio_split_to_limits() for abnormal IO (e.g. discard, etc) > * otherwise associated queue_limits won't be imposed. > + * Also split the BIO for mapped devices needing zone append > + * emulation to ensure that the BIO does not cross zone > + * boundaries. > */ > bio = bio_split_to_limits(bio); > if (!bio) > return; > } > > + /* > + * Use the block layer zone write plugging for mapped devices that > + * need zone append emulation (e.g. dm-crypt). > + */ > + if (md->emulate_zone_append && blk_zone_write_plug_bio(bio, 0)) > + return; > + > /* Only support nowait for normal IO */ > if (unlikely(bio->bi_opf & REQ_NOWAIT) && !is_abnormal) { > io = alloc_io(md, bio, GFP_NOWAIT); Would prefer to see this incremental change included from the start: diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 92ce3b2eb4ae..1fd9bbf35db3 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -1763,11 +1763,10 @@ static void dm_split_and_process_bio(struct mapped_device *md, blk_status_t error = BLK_STS_OK; bool is_abnormal, need_split; - is_abnormal = is_abnormal_io(bio); - if (likely(!md->emulate_zone_append)) - need_split = is_abnormal; - else + need_split = is_abnormal = is_abnormal_io(bio); + if (static_branch_unlikely(&zoned_enabled) && unlikely(md->emulate_zone_append)) need_split = is_abnormal || bio_straddle_zones(bio); + if (unlikely(need_split)) { /* * Use bio_split_to_limits() for abnormal IO (e.g. discard, etc) @@ -1781,12 +1780,14 @@ static void dm_split_and_process_bio(struct mapped_device *md, return; } - /* - * Use the block layer zone write plugging for mapped devices that - * need zone append emulation (e.g. dm-crypt). - */ - if (md->emulate_zone_append && blk_zone_write_plug_bio(bio, 0)) - return; + if (static_branch_unlikely(&zoned_enabled)) { + /* + * Use the block layer zone write plugging for mapped devices that + * need zone append emulation (e.g. dm-crypt). + */ + if (unlikely(md->emulate_zone_append) && blk_zone_write_plug_bio(bio, 0)) + return; + } /* Only support nowait for normal IO */ if (unlikely(bio->bi_opf & REQ_NOWAIT) && !is_abnormal) {