From 40405851af73c59678ffd8f490e6b288c7fbaf29 Mon Sep 17 00:00:00 2001 From: Jeff Moyer Date: Tue, 8 Jan 2019 16:57:34 -0500 Subject: block: clarify documentation for blk_{start|finish}_plug There was some confusion about what these functions did. Make it clear that this is a hint for upper layers to pass to the block layer, and that it does not guarantee that I/O will not be submitted between a start and finish plug. Reported-by: "Darrick J. Wong" Reviewed-by: Darrick J. Wong Reviewed-by: Ming Lei Signed-off-by: Jeff Moyer Signed-off-by: Jens Axboe --- block/blk-core.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'block') diff --git a/block/blk-core.c b/block/blk-core.c index c78042975737..f2732f106a2e 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1683,6 +1683,15 @@ EXPORT_SYMBOL(kblockd_mod_delayed_work_on); * @plug: The &struct blk_plug that needs to be initialized * * Description: + * blk_start_plug() indicates to the block layer an intent by the caller + * to submit multiple I/O requests in a batch. The block layer may use + * this hint to defer submitting I/Os from the caller until blk_finish_plug() + * is called. However, the block layer may choose to submit requests + * before a call to blk_finish_plug() if the number of queued I/Os + * exceeds %BLK_MAX_REQUEST_COUNT, or if the size of the I/O is larger than + * %BLK_PLUG_FLUSH_SIZE. The queued I/Os may also be submitted early if + * the task schedules (see below). + * * Tracking blk_plug inside the task_struct will help with auto-flushing the * pending I/O should the task end up blocking between blk_start_plug() and * blk_finish_plug(). This is important from a performance perspective, but @@ -1765,6 +1774,16 @@ void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule) blk_mq_flush_plug_list(plug, from_schedule); } +/** + * blk_finish_plug - mark the end of a batch of submitted I/O + * @plug: The &struct blk_plug passed to blk_start_plug() + * + * Description: + * Indicate that a batch of I/O submissions is complete. This function + * must be paired with an initial call to blk_start_plug(). The intent + * is to allow the block layer to optimize I/O submission. See the + * documentation for blk_start_plug() for more information. + */ void blk_finish_plug(struct blk_plug *plug) { if (plug != current->plug) -- cgit v1.2.3 From 649d4968860ba708636ad643bd52b28027367042 Mon Sep 17 00:00:00 2001 From: Jonathan Corbet Date: Wed, 9 Jan 2019 13:59:32 -0700 Subject: block: fix kerneldoc comment for blk_attempt_plug_merge() Commit 5f0ed774ed29 ("block: sum requests in the plug structure") removed the request_count parameter from block_attempt_plug_merge(), but did not remove the associated kerneldoc comment, introducing this warning to the docs build: ./block/blk-core.c:685: warning: Excess function parameter 'request_count' description in 'blk_attempt_plug_merge' Remove the obsolete description and make things a little quieter. Signed-off-by: Jonathan Corbet Signed-off-by: Jens Axboe --- block/blk-core.c | 1 - 1 file changed, 1 deletion(-) (limited to 'block') diff --git a/block/blk-core.c b/block/blk-core.c index f2732f106a2e..3c5f61ceeb67 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -661,7 +661,6 @@ no_merge: * blk_attempt_plug_merge - try to merge with %current's plugged list * @q: request_queue new bio is being queued at * @bio: new bio being queued - * @request_count: out parameter for number of traversed plugged requests * @same_queue_rq: pointer to &struct request that gets filled in when * another request associated with @q is found on the plug list * (optional, may be %NULL) -- cgit v1.2.3 From 5bf859081f6a7575a3f7509d7a70d0a9baa88ce3 Mon Sep 17 00:00:00 2001 From: Paolo Valente Date: Thu, 6 Dec 2018 19:18:19 +0100 Subject: block, bfq: fix comments on __bfq_deactivate_entity Comments on function __bfq_deactivate_entity contains two imprecise or wrong statements: 1) The function performs the deactivation of the entity. 2) The function must be invoked only if the entity is on a service tree. This commits replaces both statements with the correct ones: 1) The functions updates sched_data and service trees for the entity, so as to represent entity as inactive (which is only part of the steps needed for the deactivation of the entity). 2) The function must be invoked on every entity being deactivated. Signed-off-by: Paolo Valente Signed-off-by: Jens Axboe --- block/bfq-wf2q.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) (limited to 'block') diff --git a/block/bfq-wf2q.c b/block/bfq-wf2q.c index 63e0f12be7c9..72adbbe975d5 100644 --- a/block/bfq-wf2q.c +++ b/block/bfq-wf2q.c @@ -1154,15 +1154,14 @@ static void bfq_activate_requeue_entity(struct bfq_entity *entity, } /** - * __bfq_deactivate_entity - deactivate an entity from its service tree. - * @entity: the entity to deactivate. + * __bfq_deactivate_entity - update sched_data and service trees for + * entity, so as to represent entity as inactive + * @entity: the entity being deactivated. * @ins_into_idle_tree: if false, the entity will not be put into the * idle tree. * - * Deactivates an entity, independently of its previous state. Must - * be invoked only if entity is on a service tree. Extracts the entity - * from that tree, and if necessary and allowed, puts it into the idle - * tree. + * If necessary and allowed, puts entity into the idle tree. NOTE: + * entity may be on no tree if in service. */ bool __bfq_deactivate_entity(struct bfq_entity *entity, bool ins_into_idle_tree) { -- cgit v1.2.3 From 7809167da5c86fd6bf309b33dee7a797e263342f Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Wed, 16 Jan 2019 19:08:15 +0800 Subject: block: don't lose track of REQ_INTEGRITY flag We need to pass bio->bi_opf after bio intergrity preparing, otherwise the flag of REQ_INTEGRITY may not be set on the allocated request, then breaks block integrity. Fixes: f9afca4d367b ("blk-mq: pass in request/bio flags to queue mapping") Cc: Hannes Reinecke Cc: Keith Busch Signed-off-by: Ming Lei Signed-off-by: Jens Axboe --- block/blk-mq.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'block') diff --git a/block/blk-mq.c b/block/blk-mq.c index 3ba37b9e15e9..8f5b533764ca 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1906,7 +1906,7 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio) { const int is_sync = op_is_sync(bio->bi_opf); const int is_flush_fua = op_is_flush(bio->bi_opf); - struct blk_mq_alloc_data data = { .flags = 0, .cmd_flags = bio->bi_opf }; + struct blk_mq_alloc_data data = { .flags = 0}; struct request *rq; struct blk_plug *plug; struct request *same_queue_rq = NULL; @@ -1928,6 +1928,7 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio) rq_qos_throttle(q, bio); + data.cmd_flags = bio->bi_opf; rq = blk_mq_get_request(q, bio, &data); if (unlikely(!rq)) { rq_qos_cleanup(q, bio); -- cgit v1.2.3 From 38197ca176fc259fa4c871d07bcf8389d044a895 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Fri, 18 Jan 2019 00:14:17 +0100 Subject: block: Cleanup license notice Remove the imprecise and sloppy: "This files is licensed under the GPL." license notice in the top level comment. 1) The file already contains a SPDX license identifier which clearly states that the license of the file is GPL V2 only 2) The notice resolves to GPL v1 or later for scanners which is just contrary to the intent of SPDX identifiers to provide clear and non ambiguous license information. Aside of that the value add of this notice is below zero, Cc: Damien Le Moal Cc: Matias Bjorling Cc: Christoph Hellwig Cc: Jens Axboe Cc: linux-block@vger.kernel.org Fixes: 6a5ac9846508 ("block: Make struct request_queue smaller for CONFIG_BLK_DEV_ZONED=n") Reviewed-by: Bart Van Assche Signed-off-by: Thomas Gleixner Signed-off-by: Jens Axboe --- block/blk-mq-debugfs-zoned.c | 2 -- 1 file changed, 2 deletions(-) (limited to 'block') diff --git a/block/blk-mq-debugfs-zoned.c b/block/blk-mq-debugfs-zoned.c index fb2c82c351e4..038cb627c868 100644 --- a/block/blk-mq-debugfs-zoned.c +++ b/block/blk-mq-debugfs-zoned.c @@ -1,8 +1,6 @@ // SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) 2017 Western Digital Corporation or its affiliates. - * - * This file is released under the GPL. */ #include -- cgit v1.2.3 From 698cef173983b086977e633e46476e0f925ca01e Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Tue, 22 Jan 2019 16:20:17 +0800 Subject: block: cover another queue enter recursion via BIO_QUEUE_ENTERED Except for blk_queue_split(), bio_split() is used for splitting bio too, then the remained bio is often resubmit to queue via generic_make_request(). So the same queue enter recursion exits in this case too. Unfortunatley commit cd4a4ae4683dc2 doesn't help this case. This patch covers the above case by setting BIO_QUEUE_ENTERED before calling q->make_request_fn. In theory the per-bio flag is used to simulate one stack variable, it is just fine to clear it after q->make_request_fn is returned. Especially the same bio can't be submitted from another context. Fixes: cd4a4ae4683dc2 ("block: don't use blocking queue entered for recursive bio submits") Cc: Tetsuo Handa Cc: NeilBrown Reviewed-by: Mike Snitzer Signed-off-by: Ming Lei Signed-off-by: Jens Axboe --- block/blk-core.c | 11 +++++++++++ block/blk-merge.c | 10 ---------- 2 files changed, 11 insertions(+), 10 deletions(-) (limited to 'block') diff --git a/block/blk-core.c b/block/blk-core.c index 3c5f61ceeb67..1ccec27d20c3 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1083,7 +1083,18 @@ blk_qc_t generic_make_request(struct bio *bio) /* Create a fresh bio_list for all subordinate requests */ bio_list_on_stack[1] = bio_list_on_stack[0]; bio_list_init(&bio_list_on_stack[0]); + + /* + * Since we're recursing into make_request here, ensure + * that we mark this bio as already having entered the queue. + * If not, and the queue is going away, we can get stuck + * forever on waiting for the queue reference to drop. But + * that will never happen, as we're already holding a + * reference to it. + */ + bio_set_flag(bio, BIO_QUEUE_ENTERED); ret = q->make_request_fn(q, bio); + bio_clear_flag(bio, BIO_QUEUE_ENTERED); /* sort new bios into those for a lower level * and those for the same level diff --git a/block/blk-merge.c b/block/blk-merge.c index 71e9ac03f621..d79a22f111d1 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -272,16 +272,6 @@ void blk_queue_split(struct request_queue *q, struct bio **bio) /* there isn't chance to merge the splitted bio */ split->bi_opf |= REQ_NOMERGE; - /* - * Since we're recursing into make_request here, ensure - * that we mark this bio as already having entered the queue. - * If not, and the queue is going away, we can get stuck - * forever on waiting for the queue reference to drop. But - * that will never happen, as we're already holding a - * reference to it. - */ - bio_set_flag(*bio, BIO_QUEUE_ENTERED); - bio_chain(split, *bio); trace_block_split(q, split, (*bio)->bi_iter.bi_sector); generic_make_request(*bio); -- cgit v1.2.3 From 1c26010c5e1b9ad22a77968428b68150d27ae65f Mon Sep 17 00:00:00 2001 From: Jianchao Wang Date: Thu, 24 Jan 2019 18:28:55 +0800 Subject: blk-mq: fix the cmd_flag_name array Swap REQ_NOWAIT and REQ_NOUNMAP and add REQ_HIPRI. Acked-by: Jeff Moyer Signed-off-by: Jianchao Wang Signed-off-by: Jens Axboe --- block/blk-mq-debugfs.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'block') diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c index 90d68760af08..f8120832ca7b 100644 --- a/block/blk-mq-debugfs.c +++ b/block/blk-mq-debugfs.c @@ -308,8 +308,9 @@ static const char *const cmd_flag_name[] = { CMD_FLAG_NAME(PREFLUSH), CMD_FLAG_NAME(RAHEAD), CMD_FLAG_NAME(BACKGROUND), - CMD_FLAG_NAME(NOUNMAP), CMD_FLAG_NAME(NOWAIT), + CMD_FLAG_NAME(NOUNMAP), + CMD_FLAG_NAME(HIPRI), }; #undef CMD_FLAG_NAME -- cgit v1.2.3 From c83f536a87d9dd6d6bf989c0b0882459a902eb07 Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Wed, 23 Jan 2019 11:05:57 -0800 Subject: blk-wbt: Declare local functions static This patch avoids that sparse reports the following warnings: CHECK block/blk-wbt.c block/blk-wbt.c:600:6: warning: symbol 'wbt_issue' was not declared. Should it be static? block/blk-wbt.c:620:6: warning: symbol 'wbt_requeue' was not declared. Should it be static? CC block/blk-wbt.o block/blk-wbt.c:600:6: warning: no previous prototype for wbt_issue [-Wmissing-prototypes] void wbt_issue(struct rq_qos *rqos, struct request *rq) ^~~~~~~~~ block/blk-wbt.c:620:6: warning: no previous prototype for wbt_requeue [-Wmissing-prototypes] void wbt_requeue(struct rq_qos *rqos, struct request *rq) ^~~~~~~~~~~ Reviewed-by: Chaitanya Kulkarni Signed-off-by: Bart Van Assche Signed-off-by: Jens Axboe --- block/blk-wbt.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'block') diff --git a/block/blk-wbt.c b/block/blk-wbt.c index f0c56649775f..fd166fbb0f65 100644 --- a/block/blk-wbt.c +++ b/block/blk-wbt.c @@ -597,7 +597,7 @@ static void wbt_track(struct rq_qos *rqos, struct request *rq, struct bio *bio) rq->wbt_flags |= bio_to_wbt_flags(rwb, bio); } -void wbt_issue(struct rq_qos *rqos, struct request *rq) +static void wbt_issue(struct rq_qos *rqos, struct request *rq) { struct rq_wb *rwb = RQWB(rqos); @@ -617,7 +617,7 @@ void wbt_issue(struct rq_qos *rqos, struct request *rq) } } -void wbt_requeue(struct rq_qos *rqos, struct request *rq) +static void wbt_requeue(struct rq_qos *rqos, struct request *rq) { struct rq_wb *rwb = RQWB(rqos); if (!rwb_enabled(rwb)) -- cgit v1.2.3 From 947b7ac135b16aa60f9141ff72bd494eda0edb5e Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Sun, 27 Jan 2019 06:35:28 -0700 Subject: Revert "block: cover another queue enter recursion via BIO_QUEUE_ENTERED" We can't touch a bio after ->make_request_fn(), for all we know it could already have been completed by the time this function returns. This reverts commit 698cef173983b086977e633e46476e0f925ca01e. Reported-by: syzbot+4df6ca820108fd248943@syzkaller.appspotmail.com Signed-off-by: Jens Axboe --- block/blk-core.c | 11 ----------- block/blk-merge.c | 10 ++++++++++ 2 files changed, 10 insertions(+), 11 deletions(-) (limited to 'block') diff --git a/block/blk-core.c b/block/blk-core.c index 1ccec27d20c3..3c5f61ceeb67 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1083,18 +1083,7 @@ blk_qc_t generic_make_request(struct bio *bio) /* Create a fresh bio_list for all subordinate requests */ bio_list_on_stack[1] = bio_list_on_stack[0]; bio_list_init(&bio_list_on_stack[0]); - - /* - * Since we're recursing into make_request here, ensure - * that we mark this bio as already having entered the queue. - * If not, and the queue is going away, we can get stuck - * forever on waiting for the queue reference to drop. But - * that will never happen, as we're already holding a - * reference to it. - */ - bio_set_flag(bio, BIO_QUEUE_ENTERED); ret = q->make_request_fn(q, bio); - bio_clear_flag(bio, BIO_QUEUE_ENTERED); /* sort new bios into those for a lower level * and those for the same level diff --git a/block/blk-merge.c b/block/blk-merge.c index d79a22f111d1..71e9ac03f621 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -272,6 +272,16 @@ void blk_queue_split(struct request_queue *q, struct bio **bio) /* there isn't chance to merge the splitted bio */ split->bi_opf |= REQ_NOMERGE; + /* + * Since we're recursing into make_request here, ensure + * that we mark this bio as already having entered the queue. + * If not, and the queue is going away, we can get stuck + * forever on waiting for the queue reference to drop. But + * that will never happen, as we're already holding a + * reference to it. + */ + bio_set_flag(*bio, BIO_QUEUE_ENTERED); + bio_chain(split, *bio); trace_block_split(q, split, (*bio)->bi_iter.bi_sector); generic_make_request(*bio); -- cgit v1.2.3