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Tue, 25 Feb 2025 13:31:27 +0000 Received: from smtpav03.fra02v.mail.ibm.com (smtpav03.fra02v.mail.ibm.com [10.20.54.102]) by smtprelay06.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 51PDVPUP31654474 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 25 Feb 2025 13:31:25 GMT Received: from smtpav03.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 8240620043; Tue, 25 Feb 2025 13:31:25 +0000 (GMT) Received: from smtpav03.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 1D79720040; Tue, 25 Feb 2025 13:31:22 +0000 (GMT) Received: from li-c9696b4c-3419-11b2-a85c-f9edc3bf8a84.ibm.com.com (unknown [9.61.156.112]) by smtpav03.fra02v.mail.ibm.com (Postfix) with ESMTP; Tue, 25 Feb 2025 13:31:21 +0000 (GMT) From: Nilay Shroff To: linux-block@vger.kernel.org Cc: hch@lst.de, ming.lei@redhat.com, dlemoal@kernel.org, hare@suse.de, axboe@kernel.dk, gjoyce@ibm.com Subject: [PATCHv4 2/7] block: move q->sysfs_lock and queue-freeze under show/store method Date: Tue, 25 Feb 2025 19:00:37 +0530 Message-ID: <20250225133110.1441035-3-nilay@linux.ibm.com> X-Mailer: git-send-email 2.47.1 In-Reply-To: <20250225133110.1441035-1-nilay@linux.ibm.com> References: <20250225133110.1441035-1-nilay@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: DQqj4YZEbrIwJzl6tFSclXQJBLpjX4A5 X-Proofpoint-GUID: DQqj4YZEbrIwJzl6tFSclXQJBLpjX4A5 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1057,Hydra:6.0.680,FMLib:17.12.68.34 definitions=2025-02-25_04,2025-02-25_03,2024-11-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 impostorscore=0 bulkscore=0 mlxlogscore=999 priorityscore=1501 suspectscore=0 phishscore=0 adultscore=0 lowpriorityscore=0 mlxscore=0 spamscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2502100000 definitions=main-2502250090 In preparation to further simplify and group sysfs attributes which don't require locking or require some form of locking other than q-> limits_lock, move acquire/release of q->sysfs_lock and queue freeze/ unfreeze under each attributes' respective show/store method. While we are at it, also remove ->load_module() as it's used to load the module before queue is freezed. Now as we moved queue-freeze under ->store(), we could load module directly from the attributes' store method before we actually start freezing the queue. Currently, the ->load_module() is only used by "scheduler" attribute, so we now load the relevant elevator module before we start freezing the queue in elv_iosched_store(). Reviewed-by: Christoph Hellwig Reviewed-by: Hannes Reinecke Signed-off-by: Nilay Shroff --- block/blk-sysfs.c | 210 +++++++++++++++++++++++++++++++--------------- block/elevator.c | 20 ++++- 2 files changed, 162 insertions(+), 68 deletions(-) diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index eba5121690af..4700ee168ed5 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -28,8 +28,6 @@ struct queue_sysfs_entry { ssize_t (*store)(struct gendisk *disk, const char *page, size_t count); int (*store_limit)(struct gendisk *disk, const char *page, size_t count, struct queue_limits *lim); - - void (*load_module)(struct gendisk *disk, const char *page, size_t count); }; static ssize_t @@ -55,7 +53,12 @@ queue_var_store(unsigned long *var, const char *page, size_t count) static ssize_t queue_requests_show(struct gendisk *disk, char *page) { - return queue_var_show(disk->queue->nr_requests, page); + ssize_t ret; + + mutex_lock(&disk->queue->sysfs_lock); + ret = queue_var_show(disk->queue->nr_requests, page); + mutex_unlock(&disk->queue->sysfs_lock); + return ret; } static ssize_t @@ -63,27 +66,38 @@ queue_requests_store(struct gendisk *disk, const char *page, size_t count) { unsigned long nr; int ret, err; + unsigned int memflags; + struct request_queue *q = disk->queue; - if (!queue_is_mq(disk->queue)) + if (!queue_is_mq(q)) return -EINVAL; ret = queue_var_store(&nr, page, count); if (ret < 0) return ret; + mutex_lock(&q->sysfs_lock); + memflags = blk_mq_freeze_queue(q); if (nr < BLKDEV_MIN_RQ) nr = BLKDEV_MIN_RQ; err = blk_mq_update_nr_requests(disk->queue, nr); if (err) - return err; - + ret = err; + blk_mq_unfreeze_queue(q, memflags); + mutex_unlock(&q->sysfs_lock); return ret; } static ssize_t queue_ra_show(struct gendisk *disk, char *page) { - return queue_var_show(disk->bdi->ra_pages << (PAGE_SHIFT - 10), page); + ssize_t ret; + + mutex_lock(&disk->queue->sysfs_lock); + ret = queue_var_show(disk->bdi->ra_pages << (PAGE_SHIFT - 10), page); + mutex_unlock(&disk->queue->sysfs_lock); + + return ret; } static ssize_t @@ -91,11 +105,19 @@ queue_ra_store(struct gendisk *disk, const char *page, size_t count) { unsigned long ra_kb; ssize_t ret; + unsigned int memflags; + struct request_queue *q = disk->queue; ret = queue_var_store(&ra_kb, page, count); if (ret < 0) return ret; + + mutex_lock(&q->sysfs_lock); + memflags = blk_mq_freeze_queue(q); disk->bdi->ra_pages = ra_kb >> (PAGE_SHIFT - 10); + blk_mq_unfreeze_queue(q, memflags); + mutex_unlock(&q->sysfs_lock); + return ret; } @@ -150,7 +172,12 @@ QUEUE_SYSFS_LIMIT_SHOW_SECTORS_TO_KB(max_hw_sectors) #define QUEUE_SYSFS_SHOW_CONST(_name, _val) \ static ssize_t queue_##_name##_show(struct gendisk *disk, char *page) \ { \ - return sysfs_emit(page, "%d\n", _val); \ + ssize_t ret; \ + \ + mutex_lock(&disk->queue->sysfs_lock); \ + ret = sysfs_emit(page, "%d\n", _val); \ + mutex_unlock(&disk->queue->sysfs_lock); \ + return ret; \ } /* deprecated fields */ @@ -239,10 +266,17 @@ QUEUE_SYSFS_FEATURE_SHOW(dax, BLK_FEAT_DAX); static ssize_t queue_poll_show(struct gendisk *disk, char *page) { - if (queue_is_mq(disk->queue)) - return sysfs_emit(page, "%u\n", blk_mq_can_poll(disk->queue)); - return sysfs_emit(page, "%u\n", - !!(disk->queue->limits.features & BLK_FEAT_POLL)); + ssize_t ret; + + mutex_lock(&disk->queue->sysfs_lock); + if (queue_is_mq(disk->queue)) { + ret = sysfs_emit(page, "%u\n", blk_mq_can_poll(disk->queue)); + } else { + ret = sysfs_emit(page, "%u\n", + !!(disk->queue->limits.features & BLK_FEAT_POLL)); + } + mutex_unlock(&disk->queue->sysfs_lock); + return ret; } static ssize_t queue_zoned_show(struct gendisk *disk, char *page) @@ -254,7 +288,12 @@ static ssize_t queue_zoned_show(struct gendisk *disk, char *page) static ssize_t queue_nr_zones_show(struct gendisk *disk, char *page) { - return queue_var_show(disk_nr_zones(disk), page); + ssize_t ret; + + mutex_lock(&disk->queue->sysfs_lock); + ret = queue_var_show(disk_nr_zones(disk), page); + mutex_unlock(&disk->queue->sysfs_lock); + return ret; } static ssize_t queue_iostats_passthrough_show(struct gendisk *disk, char *page) @@ -281,35 +320,51 @@ static int queue_iostats_passthrough_store(struct gendisk *disk, static ssize_t queue_nomerges_show(struct gendisk *disk, char *page) { - return queue_var_show((blk_queue_nomerges(disk->queue) << 1) | + ssize_t ret; + + mutex_lock(&disk->queue->sysfs_lock); + ret = queue_var_show((blk_queue_nomerges(disk->queue) << 1) | blk_queue_noxmerges(disk->queue), page); + mutex_unlock(&disk->queue->sysfs_lock); + return ret; } static ssize_t queue_nomerges_store(struct gendisk *disk, const char *page, size_t count) { unsigned long nm; + unsigned int memflags; + struct request_queue *q = disk->queue; ssize_t ret = queue_var_store(&nm, page, count); if (ret < 0) return ret; - blk_queue_flag_clear(QUEUE_FLAG_NOMERGES, disk->queue); - blk_queue_flag_clear(QUEUE_FLAG_NOXMERGES, disk->queue); + mutex_lock(&q->sysfs_lock); + memflags = blk_mq_freeze_queue(q); + blk_queue_flag_clear(QUEUE_FLAG_NOMERGES, q); + blk_queue_flag_clear(QUEUE_FLAG_NOXMERGES, q); if (nm == 2) - blk_queue_flag_set(QUEUE_FLAG_NOMERGES, disk->queue); + blk_queue_flag_set(QUEUE_FLAG_NOMERGES, q); else if (nm) - blk_queue_flag_set(QUEUE_FLAG_NOXMERGES, disk->queue); + blk_queue_flag_set(QUEUE_FLAG_NOXMERGES, q); + blk_mq_unfreeze_queue(q, memflags); + mutex_unlock(&q->sysfs_lock); return ret; } static ssize_t queue_rq_affinity_show(struct gendisk *disk, char *page) { - bool set = test_bit(QUEUE_FLAG_SAME_COMP, &disk->queue->queue_flags); - bool force = test_bit(QUEUE_FLAG_SAME_FORCE, &disk->queue->queue_flags); + ssize_t ret; + bool set, force; - return queue_var_show(set << force, page); + mutex_lock(&disk->queue->sysfs_lock); + set = test_bit(QUEUE_FLAG_SAME_COMP, &disk->queue->queue_flags); + force = test_bit(QUEUE_FLAG_SAME_FORCE, &disk->queue->queue_flags); + ret = queue_var_show(set << force, page); + mutex_unlock(&disk->queue->sysfs_lock); + return ret; } static ssize_t @@ -319,11 +374,14 @@ queue_rq_affinity_store(struct gendisk *disk, const char *page, size_t count) #ifdef CONFIG_SMP struct request_queue *q = disk->queue; unsigned long val; + unsigned int memflags; ret = queue_var_store(&val, page, count); if (ret < 0) return ret; + mutex_lock(&q->sysfs_lock); + memflags = blk_mq_freeze_queue(q); if (val == 2) { blk_queue_flag_set(QUEUE_FLAG_SAME_COMP, q); blk_queue_flag_set(QUEUE_FLAG_SAME_FORCE, q); @@ -334,6 +392,8 @@ queue_rq_affinity_store(struct gendisk *disk, const char *page, size_t count) blk_queue_flag_clear(QUEUE_FLAG_SAME_COMP, q); blk_queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q); } + blk_mq_unfreeze_queue(q, memflags); + mutex_unlock(&q->sysfs_lock); #endif return ret; } @@ -347,29 +407,52 @@ static ssize_t queue_poll_delay_store(struct gendisk *disk, const char *page, static ssize_t queue_poll_store(struct gendisk *disk, const char *page, size_t count) { - if (!(disk->queue->limits.features & BLK_FEAT_POLL)) - return -EINVAL; + unsigned int memflags; + ssize_t ret = count; + struct request_queue *q = disk->queue; + + mutex_lock(&q->sysfs_lock); + memflags = blk_mq_freeze_queue(q); + if (!(q->limits.features & BLK_FEAT_POLL)) { + ret = -EINVAL; + goto out; + } pr_info_ratelimited("writes to the poll attribute are ignored.\n"); pr_info_ratelimited("please use driver specific parameters instead.\n"); - return count; +out: + blk_mq_unfreeze_queue(q, memflags); + mutex_unlock(&q->sysfs_lock); + + return ret; } static ssize_t queue_io_timeout_show(struct gendisk *disk, char *page) { - return sysfs_emit(page, "%u\n", jiffies_to_msecs(disk->queue->rq_timeout)); + ssize_t ret; + + mutex_lock(&disk->queue->sysfs_lock); + ret = sysfs_emit(page, "%u\n", + jiffies_to_msecs(disk->queue->rq_timeout)); + mutex_unlock(&disk->queue->sysfs_lock); + return ret; } static ssize_t queue_io_timeout_store(struct gendisk *disk, const char *page, size_t count) { - unsigned int val; + unsigned int val, memflags; int err; + struct request_queue *q = disk->queue; err = kstrtou32(page, 10, &val); if (err || val == 0) return -EINVAL; - blk_queue_rq_timeout(disk->queue, msecs_to_jiffies(val)); + mutex_lock(&q->sysfs_lock); + memflags = blk_mq_freeze_queue(q); + blk_queue_rq_timeout(q, msecs_to_jiffies(val)); + blk_mq_unfreeze_queue(q, memflags); + mutex_unlock(&q->sysfs_lock); return count; } @@ -428,14 +511,6 @@ static struct queue_sysfs_entry _prefix##_entry = { \ .store_limit = _prefix##_store, \ } -#define QUEUE_RW_LOAD_MODULE_ENTRY(_prefix, _name) \ -static struct queue_sysfs_entry _prefix##_entry = { \ - .attr = { .name = _name, .mode = 0644 }, \ - .show = _prefix##_show, \ - .load_module = _prefix##_load_module, \ - .store = _prefix##_store, \ -} - QUEUE_RW_ENTRY(queue_requests, "nr_requests"); QUEUE_RW_ENTRY(queue_ra, "read_ahead_kb"); QUEUE_LIM_RW_ENTRY(queue_max_sectors, "max_sectors_kb"); @@ -443,7 +518,7 @@ QUEUE_LIM_RO_ENTRY(queue_max_hw_sectors, "max_hw_sectors_kb"); QUEUE_LIM_RO_ENTRY(queue_max_segments, "max_segments"); QUEUE_LIM_RO_ENTRY(queue_max_integrity_segments, "max_integrity_segments"); QUEUE_LIM_RO_ENTRY(queue_max_segment_size, "max_segment_size"); -QUEUE_RW_LOAD_MODULE_ENTRY(elv_iosched, "scheduler"); +QUEUE_RW_ENTRY(elv_iosched, "scheduler"); QUEUE_LIM_RO_ENTRY(queue_logical_block_size, "logical_block_size"); QUEUE_LIM_RO_ENTRY(queue_physical_block_size, "physical_block_size"); @@ -512,14 +587,24 @@ static ssize_t queue_var_store64(s64 *var, const char *page) static ssize_t queue_wb_lat_show(struct gendisk *disk, char *page) { - if (!wbt_rq_qos(disk->queue)) - return -EINVAL; + ssize_t ret; + struct request_queue *q = disk->queue; - if (wbt_disabled(disk->queue)) - return sysfs_emit(page, "0\n"); + mutex_lock(&q->sysfs_lock); + if (!wbt_rq_qos(q)) { + ret = -EINVAL; + goto out; + } - return sysfs_emit(page, "%llu\n", - div_u64(wbt_get_min_lat(disk->queue), 1000)); + if (wbt_disabled(q)) { + ret = sysfs_emit(page, "0\n"); + goto out; + } + + ret = sysfs_emit(page, "%llu\n", div_u64(wbt_get_min_lat(q), 1000)); +out: + mutex_unlock(&q->sysfs_lock); + return ret; } static ssize_t queue_wb_lat_store(struct gendisk *disk, const char *page, @@ -529,6 +614,7 @@ static ssize_t queue_wb_lat_store(struct gendisk *disk, const char *page, struct rq_qos *rqos; ssize_t ret; s64 val; + unsigned int memflags; ret = queue_var_store64(&val, page); if (ret < 0) @@ -536,20 +622,24 @@ static ssize_t queue_wb_lat_store(struct gendisk *disk, const char *page, if (val < -1) return -EINVAL; + mutex_lock(&q->sysfs_lock); + memflags = blk_mq_freeze_queue(q); + rqos = wbt_rq_qos(q); if (!rqos) { ret = wbt_init(disk); if (ret) - return ret; + goto out; } + ret = count; if (val == -1) val = wbt_default_latency_nsec(q); else if (val >= 0) val *= 1000ULL; if (wbt_get_min_lat(q) == val) - return count; + goto out; /* * Ensure that the queue is idled, in case the latency update @@ -561,8 +651,11 @@ static ssize_t queue_wb_lat_store(struct gendisk *disk, const char *page, wbt_set_min_lat(q, val); blk_mq_unquiesce_queue(q); +out: + blk_mq_unfreeze_queue(q, memflags); + mutex_unlock(&q->sysfs_lock); - return count; + return ret; } QUEUE_RW_ENTRY(queue_wb_lat, "wbt_lat_usec"); @@ -684,22 +777,20 @@ queue_attr_show(struct kobject *kobj, struct attribute *attr, char *page) { struct queue_sysfs_entry *entry = to_queue(attr); struct gendisk *disk = container_of(kobj, struct gendisk, queue_kobj); - ssize_t res; if (!entry->show && !entry->show_limit) return -EIO; if (entry->show_limit) { + ssize_t res; + mutex_lock(&disk->queue->limits_lock); res = entry->show_limit(disk, page); mutex_unlock(&disk->queue->limits_lock); return res; } - mutex_lock(&disk->queue->sysfs_lock); - res = entry->show(disk, page); - mutex_unlock(&disk->queue->sysfs_lock); - return res; + return entry->show(disk, page); } static ssize_t @@ -709,21 +800,13 @@ queue_attr_store(struct kobject *kobj, struct attribute *attr, struct queue_sysfs_entry *entry = to_queue(attr); struct gendisk *disk = container_of(kobj, struct gendisk, queue_kobj); struct request_queue *q = disk->queue; - unsigned int memflags; - ssize_t res; if (!entry->store_limit && !entry->store) return -EIO; - /* - * If the attribute needs to load a module, do it before freezing the - * queue to ensure that the module file can be read when the request - * queue is the one for the device storing the module file. - */ - if (entry->load_module) - entry->load_module(disk, page, length); - if (entry->store_limit) { + ssize_t res; + struct queue_limits lim = queue_limits_start_update(q); res = entry->store_limit(disk, page, length, &lim); @@ -738,12 +821,7 @@ queue_attr_store(struct kobject *kobj, struct attribute *attr, return length; } - mutex_lock(&q->sysfs_lock); - memflags = blk_mq_freeze_queue(q); - res = entry->store(disk, page, length); - blk_mq_unfreeze_queue(q, memflags); - mutex_unlock(&q->sysfs_lock); - return res; + return entry->store(disk, page, length); } static const struct sysfs_ops queue_sysfs_ops = { diff --git a/block/elevator.c b/block/elevator.c index cd2ce4921601..041f1d983bc7 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -723,11 +723,24 @@ ssize_t elv_iosched_store(struct gendisk *disk, const char *buf, { char elevator_name[ELV_NAME_MAX]; int ret; + unsigned int memflags; + struct request_queue *q = disk->queue; + /* + * If the attribute needs to load a module, do it before freezing the + * queue to ensure that the module file can be read when the request + * queue is the one for the device storing the module file. + */ + elv_iosched_load_module(disk, buf, count); strscpy(elevator_name, buf, sizeof(elevator_name)); - ret = elevator_change(disk->queue, strstrip(elevator_name)); + + mutex_lock(&q->sysfs_lock); + memflags = blk_mq_freeze_queue(q); + ret = elevator_change(q, strstrip(elevator_name)); if (!ret) - return count; + ret = count; + blk_mq_unfreeze_queue(q, memflags); + mutex_unlock(&q->sysfs_lock); return ret; } @@ -738,6 +751,7 @@ ssize_t elv_iosched_show(struct gendisk *disk, char *name) struct elevator_type *cur = NULL, *e; int len = 0; + mutex_lock(&q->sysfs_lock); if (!q->elevator) { len += sprintf(name+len, "[none] "); } else { @@ -755,6 +769,8 @@ ssize_t elv_iosched_show(struct gendisk *disk, char *name) spin_unlock(&elv_list_lock); len += sprintf(name+len, "\n"); + mutex_unlock(&q->sysfs_lock); + return len; }