diff options
-rw-r--r-- | block/blk-cgroup.c | 37 | ||||
-rw-r--r-- | block/blk-core.c | 15 | ||||
-rw-r--r-- | block/blk-softirq.c | 2 | ||||
-rw-r--r-- | block/blk-sysfs.c | 10 | ||||
-rw-r--r-- | block/cfq-iosched.c | 20 | ||||
-rw-r--r-- | drivers/block/floppy.c | 8 | ||||
-rw-r--r-- | drivers/block/xen-blkback/common.h | 2 | ||||
-rw-r--r-- | drivers/block/xen-blkback/xenbus.c | 6 | ||||
-rw-r--r-- | drivers/mmc/card/block.c | 3 | ||||
-rw-r--r-- | fs/ext3/inode.c | 4 | ||||
-rw-r--r-- | fs/ext3/namei.c | 3 | ||||
-rw-r--r-- | fs/ext4/inode.c | 4 | ||||
-rw-r--r-- | fs/ext4/namei.c | 3 | ||||
-rw-r--r-- | fs/gfs2/log.c | 4 | ||||
-rw-r--r-- | fs/gfs2/meta_io.c | 6 | ||||
-rw-r--r-- | fs/gfs2/ops_fstype.c | 2 | ||||
-rw-r--r-- | fs/gfs2/quota.c | 2 | ||||
-rw-r--r-- | include/linux/blk_types.h | 6 | ||||
-rw-r--r-- | include/linux/blkdev.h | 1 | ||||
-rw-r--r-- | include/linux/fs.h | 2 | ||||
-rw-r--r-- | mm/backing-dev.c | 30 |
21 files changed, 92 insertions, 78 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index bcaf16ee6ad..b596e54ddd7 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -785,10 +785,10 @@ static int blkio_policy_parse_and_set(char *buf, { char *s[4], *p, *major_s = NULL, *minor_s = NULL; int ret; - unsigned long major, minor, temp; + unsigned long major, minor; int i = 0; dev_t dev; - u64 bps, iops; + u64 temp; memset(s, 0, sizeof(s)); @@ -826,20 +826,23 @@ static int blkio_policy_parse_and_set(char *buf, dev = MKDEV(major, minor); - ret = blkio_check_dev_num(dev); + ret = strict_strtoull(s[1], 10, &temp); if (ret) - return ret; + return -EINVAL; - newpn->dev = dev; + /* For rule removal, do not check for device presence. */ + if (temp) { + ret = blkio_check_dev_num(dev); + if (ret) + return ret; + } - if (s[1] == NULL) - return -EINVAL; + newpn->dev = dev; switch (plid) { case BLKIO_POLICY_PROP: - ret = strict_strtoul(s[1], 10, &temp); - if (ret || (temp < BLKIO_WEIGHT_MIN && temp > 0) || - temp > BLKIO_WEIGHT_MAX) + if ((temp < BLKIO_WEIGHT_MIN && temp > 0) || + temp > BLKIO_WEIGHT_MAX) return -EINVAL; newpn->plid = plid; @@ -850,26 +853,18 @@ static int blkio_policy_parse_and_set(char *buf, switch(fileid) { case BLKIO_THROTL_read_bps_device: case BLKIO_THROTL_write_bps_device: - ret = strict_strtoull(s[1], 10, &bps); - if (ret) - return -EINVAL; - newpn->plid = plid; newpn->fileid = fileid; - newpn->val.bps = bps; + newpn->val.bps = temp; break; case BLKIO_THROTL_read_iops_device: case BLKIO_THROTL_write_iops_device: - ret = strict_strtoull(s[1], 10, &iops); - if (ret) - return -EINVAL; - - if (iops > THROTL_IOPS_MAX) + if (temp > THROTL_IOPS_MAX) return -EINVAL; newpn->plid = plid; newpn->fileid = fileid; - newpn->val.iops = (unsigned int)iops; + newpn->val.iops = (unsigned int)temp; break; } break; diff --git a/block/blk-core.c b/block/blk-core.c index 90e1ffdeb41..b2ed78afd9f 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1167,7 +1167,7 @@ static bool bio_attempt_front_merge(struct request_queue *q, * true if merge was successful, otherwise false. */ static bool attempt_plug_merge(struct task_struct *tsk, struct request_queue *q, - struct bio *bio) + struct bio *bio, unsigned int *request_count) { struct blk_plug *plug; struct request *rq; @@ -1176,10 +1176,13 @@ static bool attempt_plug_merge(struct task_struct *tsk, struct request_queue *q, plug = tsk->plug; if (!plug) goto out; + *request_count = 0; list_for_each_entry_reverse(rq, &plug->list, queuelist) { int el_ret; + (*request_count)++; + if (rq->q != q) continue; @@ -1219,6 +1222,7 @@ static int __make_request(struct request_queue *q, struct bio *bio) struct blk_plug *plug; int el_ret, rw_flags, where = ELEVATOR_INSERT_SORT; struct request *req; + unsigned int request_count = 0; /* * low level driver can indicate that it wants pages above a @@ -1237,7 +1241,7 @@ static int __make_request(struct request_queue *q, struct bio *bio) * Check if we can merge with the plugged list before grabbing * any locks. */ - if (attempt_plug_merge(current, q, bio)) + if (attempt_plug_merge(current, q, bio, &request_count)) goto out; spin_lock_irq(q->queue_lock); @@ -1302,11 +1306,10 @@ get_rq: if (__rq->q != q) plug->should_sort = 1; } + if (request_count >= BLK_MAX_REQUEST_COUNT) + blk_flush_plug_list(plug, false); list_add_tail(&req->queuelist, &plug->list); - plug->count++; drive_stat_acct(req, 1); - if (plug->count >= BLK_MAX_REQUEST_COUNT) - blk_flush_plug_list(plug, false); } else { spin_lock_irq(q->queue_lock); add_acct_request(q, req, where); @@ -2634,7 +2637,6 @@ void blk_start_plug(struct blk_plug *plug) INIT_LIST_HEAD(&plug->list); INIT_LIST_HEAD(&plug->cb_list); plug->should_sort = 0; - plug->count = 0; /* * If this is a nested plug, don't actually assign it. It will be @@ -2718,7 +2720,6 @@ void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule) return; list_splice_init(&plug->list, &list); - plug->count = 0; if (plug->should_sort) { list_sort(NULL, &list, plug_rq_cmp); diff --git a/block/blk-softirq.c b/block/blk-softirq.c index 58340d0cb23..1366a89d8e6 100644 --- a/block/blk-softirq.c +++ b/block/blk-softirq.c @@ -115,7 +115,7 @@ void __blk_complete_request(struct request *req) /* * Select completion CPU */ - if (test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags) && req->cpu != -1) { + if (req->cpu != -1) { ccpu = req->cpu; if (!test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags)) { ccpu = blk_cpu_to_group(ccpu); diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index 0ee17b5e7fb..e681805cdb4 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -258,11 +258,13 @@ queue_rq_affinity_store(struct request_queue *q, const char *page, size_t count) ret = queue_var_store(&val, page, count); spin_lock_irq(q->queue_lock); - if (val) { + if (val == 2) { queue_flag_set(QUEUE_FLAG_SAME_COMP, q); - if (val == 2) - queue_flag_set(QUEUE_FLAG_SAME_FORCE, q); - } else { + queue_flag_set(QUEUE_FLAG_SAME_FORCE, q); + } else if (val == 1) { + queue_flag_set(QUEUE_FLAG_SAME_COMP, q); + queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q); + } else if (val == 0) { queue_flag_clear(QUEUE_FLAG_SAME_COMP, q); queue_flag_clear(QUEUE_FLAG_SAME_FORCE, q); } diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index a33bd4377c6..16ace89613b 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -130,8 +130,8 @@ struct cfq_queue { unsigned long slice_end; long slice_resid; - /* pending metadata requests */ - int meta_pending; + /* pending priority requests */ + int prio_pending; /* number of requests that are on the dispatch list or inside driver */ int dispatched; @@ -684,8 +684,8 @@ cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2, if (rq_is_sync(rq1) != rq_is_sync(rq2)) return rq_is_sync(rq1) ? rq1 : rq2; - if ((rq1->cmd_flags ^ rq2->cmd_flags) & REQ_META) - return rq1->cmd_flags & REQ_META ? rq1 : rq2; + if ((rq1->cmd_flags ^ rq2->cmd_flags) & REQ_PRIO) + return rq1->cmd_flags & REQ_PRIO ? rq1 : rq2; s1 = blk_rq_pos(rq1); s2 = blk_rq_pos(rq2); @@ -1612,9 +1612,9 @@ static void cfq_remove_request(struct request *rq) cfqq->cfqd->rq_queued--; cfq_blkiocg_update_io_remove_stats(&(RQ_CFQG(rq))->blkg, rq_data_dir(rq), rq_is_sync(rq)); - if (rq->cmd_flags & REQ_META) { - WARN_ON(!cfqq->meta_pending); - cfqq->meta_pending--; + if (rq->cmd_flags & REQ_PRIO) { + WARN_ON(!cfqq->prio_pending); + cfqq->prio_pending--; } } @@ -3372,7 +3372,7 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, * So both queues are sync. Let the new request get disk time if * it's a metadata request and the current queue is doing regular IO. */ - if ((rq->cmd_flags & REQ_META) && !cfqq->meta_pending) + if ((rq->cmd_flags & REQ_PRIO) && !cfqq->prio_pending) return true; /* @@ -3439,8 +3439,8 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, struct cfq_io_context *cic = RQ_CIC(rq); cfqd->rq_queued++; - if (rq->cmd_flags & REQ_META) - cfqq->meta_pending++; + if (rq->cmd_flags & REQ_PRIO) + cfqq->prio_pending++; cfq_update_io_thinktime(cfqd, cfqq, cic); cfq_update_io_seektime(cfqd, cfqq, rq); diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c index 98de8f41867..9955a53733b 100644 --- a/drivers/block/floppy.c +++ b/drivers/block/floppy.c @@ -4250,7 +4250,7 @@ static int __init floppy_init(void) use_virtual_dma = can_use_virtual_dma & 1; fdc_state[0].address = FDC1; if (fdc_state[0].address == -1) { - del_timer(&fd_timeout); + del_timer_sync(&fd_timeout); err = -ENODEV; goto out_unreg_region; } @@ -4261,7 +4261,7 @@ static int __init floppy_init(void) fdc = 0; /* reset fdc in case of unexpected interrupt */ err = floppy_grab_irq_and_dma(); if (err) { - del_timer(&fd_timeout); + del_timer_sync(&fd_timeout); err = -EBUSY; goto out_unreg_region; } @@ -4318,7 +4318,7 @@ static int __init floppy_init(void) user_reset_fdc(-1, FD_RESET_ALWAYS, false); } fdc = 0; - del_timer(&fd_timeout); + del_timer_sync(&fd_timeout); current_drive = 0; initialized = true; if (have_no_fdc) { @@ -4368,7 +4368,7 @@ out_unreg_blkdev: unregister_blkdev(FLOPPY_MAJOR, "fd"); out_put_disk: while (dr--) { - del_timer(&motor_off_timer[dr]); + del_timer_sync(&motor_off_timer[dr]); if (disks[dr]->queue) blk_cleanup_queue(disks[dr]->queue); put_disk(disks[dr]); diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen-blkback/common.h index 9e40b283a46..00c57c90e2d 100644 --- a/drivers/block/xen-blkback/common.h +++ b/drivers/block/xen-blkback/common.h @@ -46,7 +46,7 @@ #define DRV_PFX "xen-blkback:" #define DPRINTK(fmt, args...) \ - pr_debug(DRV_PFX "(%s:%d) " fmt ".\n", \ + pr_debug(DRV_PFX "(%s:%d) " fmt ".\n", \ __func__, __LINE__, ##args) diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c index 3f129b45451..5fd2010f7d2 100644 --- a/drivers/block/xen-blkback/xenbus.c +++ b/drivers/block/xen-blkback/xenbus.c @@ -590,7 +590,7 @@ static void frontend_changed(struct xenbus_device *dev, /* * Enforce precondition before potential leak point. - * blkif_disconnect() is idempotent. + * xen_blkif_disconnect() is idempotent. */ xen_blkif_disconnect(be->blkif); @@ -601,17 +601,17 @@ static void frontend_changed(struct xenbus_device *dev, break; case XenbusStateClosing: - xen_blkif_disconnect(be->blkif); xenbus_switch_state(dev, XenbusStateClosing); break; case XenbusStateClosed: + xen_blkif_disconnect(be->blkif); xenbus_switch_state(dev, XenbusStateClosed); if (xenbus_dev_is_online(dev)) break; /* fall through if not online */ case XenbusStateUnknown: - /* implies blkif_disconnect() via blkback_remove() */ + /* implies xen_blkif_disconnect() via xen_blkbk_remove() */ device_unregister(&dev->dev); break; diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c index 1ff5486213f..4c1a648d00f 100644 --- a/drivers/mmc/card/block.c +++ b/drivers/mmc/card/block.c @@ -926,6 +926,9 @@ static void mmc_blk_rw_rq_prep(struct mmc_queue_req *mqrq, /* * Reliable writes are used to implement Forced Unit Access and * REQ_META accesses, and are supported only on MMCs. + * + * XXX: this really needs a good explanation of why REQ_META + * is treated special. */ bool do_rel_wr = ((req->cmd_flags & REQ_FUA) || (req->cmd_flags & REQ_META)) && diff --git a/fs/ext3/inode.c b/fs/ext3/inode.c index 04da6acde85..12661e1deed 100644 --- a/fs/ext3/inode.c +++ b/fs/ext3/inode.c @@ -1134,7 +1134,7 @@ struct buffer_head *ext3_bread(handle_t *handle, struct inode *inode, return bh; if (buffer_uptodate(bh)) return bh; - ll_rw_block(READ_META, 1, &bh); + ll_rw_block(READ | REQ_META | REQ_PRIO, 1, &bh); wait_on_buffer(bh); if (buffer_uptodate(bh)) return bh; @@ -2807,7 +2807,7 @@ make_io: trace_ext3_load_inode(inode); get_bh(bh); bh->b_end_io = end_buffer_read_sync; - submit_bh(READ_META, bh); + submit_bh(READ | REQ_META | REQ_PRIO, bh); wait_on_buffer(bh); if (!buffer_uptodate(bh)) { ext3_error(inode->i_sb, "ext3_get_inode_loc", diff --git a/fs/ext3/namei.c b/fs/ext3/namei.c index 5571708b6a5..0629e09f651 100644 --- a/fs/ext3/namei.c +++ b/fs/ext3/namei.c @@ -922,7 +922,8 @@ restart: bh = ext3_getblk(NULL, dir, b++, 0, &err); bh_use[ra_max] = bh; if (bh) - ll_rw_block(READ_META, 1, &bh); + ll_rw_block(READ | REQ_META | REQ_PRIO, + 1, &bh); } } if ((bh = bh_use[ra_ptr++]) == NULL) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 18d2558b762..986e2388f03 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -647,7 +647,7 @@ struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode, return bh; if (buffer_uptodate(bh)) return bh; - ll_rw_block(READ_META, 1, &bh); + ll_rw_block(READ | REQ_META | REQ_PRIO, 1, &bh); wait_on_buffer(bh); if (buffer_uptodate(bh)) return bh; @@ -3298,7 +3298,7 @@ make_io: trace_ext4_load_inode(inode); get_bh(bh); bh->b_end_io = end_buffer_read_sync; - submit_bh(READ_META, bh); + submit_bh(READ | REQ_META | REQ_PRIO, bh); wait_on_buffer(bh); if (!buffer_uptodate(bh)) { EXT4_ERROR_INODE_BLOCK(inode, block, diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index f8068c7bae9..1c924faeb6c 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -922,7 +922,8 @@ restart: bh = ext4_getblk(NULL, dir, b++, 0, &err); bh_use[ra_max] = bh; if (bh) - ll_rw_block(READ_META, 1, &bh); + ll_rw_block(READ | REQ_META | REQ_PRIO, + 1, &bh); } } if ((bh = bh_use[ra_ptr++]) == NULL) diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c index 85c62923ee2..59864643436 100644 --- a/fs/gfs2/log.c +++ b/fs/gfs2/log.c @@ -624,9 +624,9 @@ static void log_write_header(struct gfs2_sbd *sdp, u32 flags, int pull) bh->b_end_io = end_buffer_write_sync; get_bh(bh); if (test_bit(SDF_NOBARRIERS, &sdp->sd_flags)) - submit_bh(WRITE_SYNC | REQ_META, bh); + submit_bh(WRITE_SYNC | REQ_META | REQ_PRIO, bh); else - submit_bh(WRITE_FLUSH_FUA | REQ_META, bh); + submit_bh(WRITE_FLUSH_FUA | REQ_META | REQ_PRIO, bh); wait_on_buffer(bh); if (!buffer_uptodate(bh)) diff --git a/fs/gfs2/meta_io.c b/fs/gfs2/meta_io.c index 747238cd9f9..be29858900f 100644 --- a/fs/gfs2/meta_io.c +++ b/fs/gfs2/meta_io.c @@ -37,7 +37,7 @@ static int gfs2_aspace_writepage(struct page *page, struct writeback_control *wb { struct buffer_head *bh, *head; int nr_underway = 0; - int write_op = REQ_META | + int write_op = REQ_META | REQ_PRIO | (wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC : WRITE); BUG_ON(!PageLocked(page)); @@ -225,7 +225,7 @@ int gfs2_meta_read(struct gfs2_glock *gl, u64 blkno, int flags, } bh->b_end_io = end_buffer_read_sync; get_bh(bh); - submit_bh(READ_SYNC | REQ_META, bh); + submit_bh(READ_SYNC | REQ_META | REQ_PRIO, bh); if (!(flags & DIO_WAIT)) return 0; @@ -435,7 +435,7 @@ struct buffer_head *gfs2_meta_ra(struct gfs2_glock *gl, u64 dblock, u32 extlen) if (buffer_uptodate(first_bh)) goto out; if (!buffer_locked(first_bh)) - ll_rw_block(READ_SYNC | REQ_META, 1, &first_bh); + ll_rw_block(READ_SYNC | REQ_META | REQ_PRIO, 1, &first_bh); dblock++; extlen--; diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c index 3bc073a4cf8..079587e5384 100644 --- a/fs/gfs2/ops_fstype.c +++ b/fs/gfs2/ops_fstype.c @@ -224,7 +224,7 @@ static int gfs2_read_super(struct gfs2_sbd *sdp, sector_t sector, int silent) bio->bi_end_io = end_bio_io_page; bio->bi_private = page; - submit_bio(READ_SYNC | REQ_META, bio); + submit_bio(READ_SYNC | REQ_META | REQ_PRIO, bio); wait_on_page_locked(page); bio_put(bio); if (!PageUptodate(page)) { diff --git a/fs/gfs2/quota.c b/fs/gfs2/quota.c index 42e8d23bc04..0e8bb13381e 100644 --- a/fs/gfs2/quota.c +++ b/fs/gfs2/quota.c @@ -709,7 +709,7 @@ get_a_page: set_buffer_uptodate(bh); if (!buffer_uptodate(bh)) { - ll_rw_block(READ_META, 1, &bh); + ll_rw_block(READ | REQ_META | REQ_PRIO, 1, &bh); wait_on_buffer(bh); if (!buffer_uptodate(bh)) goto unlock_out; diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h index 32f0076e844..71fc53bb8f1 100644 --- a/include/linux/blk_types.h +++ b/include/linux/blk_types.h @@ -124,6 +124,7 @@ enum rq_flag_bits { __REQ_SYNC, /* request is sync (sync write or read) */ __REQ_META, /* metadata io request */ + __REQ_PRIO, /* boost priority in cfq */ __REQ_DISCARD, /* request to discard sectors */ __REQ_SECURE, /* secure discard (used with __REQ_DISCARD) */ @@ -161,14 +162,15 @@ enum rq_flag_bits { #define REQ_FAILFAST_DRIVER (1 << __REQ_FAILFAST_DRIVER) #define REQ_SYNC (1 << __REQ_SYNC) #define REQ_META (1 << __REQ_META) +#define REQ_PRIO (1 << __REQ_PRIO) #define REQ_DISCARD (1 << __REQ_DISCARD) #define REQ_NOIDLE (1 << __REQ_NOIDLE) #define REQ_FAILFAST_MASK \ (REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT | REQ_FAILFAST_DRIVER) #define REQ_COMMON_MASK \ - (REQ_WRITE | REQ_FAILFAST_MASK | REQ_SYNC | REQ_META | REQ_DISCARD | \ - REQ_NOIDLE | REQ_FLUSH | REQ_FUA | REQ_SECURE) + (REQ_WRITE | REQ_FAILFAST_MASK | REQ_SYNC | REQ_META | REQ_PRIO | \ + REQ_DISCARD | REQ_NOIDLE | REQ_FLUSH | REQ_FUA | REQ_SECURE) #define REQ_CLONE_MASK REQ_COMMON_MASK #define REQ_RAHEAD (1 << __REQ_RAHEAD) diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 84b15d54f8c..7fbaa910334 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -873,7 +873,6 @@ struct blk_plug { struct list_head list; struct list_head cb_list; unsigned int should_sort; - unsigned int count; }; #define BLK_MAX_REQUEST_COUNT 16 diff --git a/include/linux/fs.h b/include/linux/fs.h index c2bd68f2277..277f497923a 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -162,10 +162,8 @@ struct inodes_stat_t { #define READA RWA_MASK #define READ_SYNC (READ | REQ_SYNC) -#define READ_META (READ | REQ_META) #define WRITE_SYNC (WRITE | REQ_SYNC | REQ_NOIDLE) #define WRITE_ODIRECT (WRITE | REQ_SYNC) -#define WRITE_META (WRITE | REQ_META) #define WRITE_FLUSH (WRITE | REQ_SYNC | REQ_NOIDLE | REQ_FLUSH) #define WRITE_FUA (WRITE | REQ_SYNC | REQ_NOIDLE | REQ_FUA) #define WRITE_FLUSH_FUA (WRITE | REQ_SYNC | REQ_NOIDLE | REQ_FLUSH | REQ_FUA) diff --git a/mm/backing-dev.c b/mm/backing-dev.c index d6edf8d14f9..a87da524a4a 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -359,6 +359,17 @@ static unsigned long bdi_longest_inactive(void) return max(5UL * 60 * HZ, interval); } +/* + * Clear pending bit and wakeup anybody waiting for flusher thread creation or + * shutdown + */ +static void bdi_clear_pending(struct backing_dev_info *bdi) +{ + clear_bit(BDI_pending, &bdi->state); + smp_mb__after_clear_bit(); + wake_up_bit(&bdi->state, BDI_pending); +} + static int bdi_forker_thread(void *ptr) { struct bdi_writeback *me = ptr; @@ -390,6 +401,13 @@ static int bdi_forker_thread(void *ptr) } spin_lock_bh(&bdi_lock); + /* + * In the following loop we are going to check whether we have + * some work to do without any synchronization with tasks + * waking us up to do work for them. So we have to set task + * state already here so that we don't miss wakeups coming + * after we verify some condition. + */ set_current_state(TASK_INTERRUPTIBLE); list_for_each_entry(bdi, &bdi_list, bdi_list) { @@ -469,11 +487,13 @@ static int bdi_forker_thread(void *ptr) spin_unlock_bh(&bdi->wb_lock); wake_up_process(task); } + bdi_clear_pending(bdi); break; case KILL_THREAD: __set_current_state(TASK_RUNNING); kthread_stop(task); + bdi_clear_pending(bdi); break; case NO_ACTION: @@ -489,16 +509,8 @@ static int bdi_forker_thread(void *ptr) else schedule_timeout(msecs_to_jiffies(dirty_writeback_interval * 10)); try_to_freeze(); - /* Back to the main loop */ - continue; + break; } - - /* - * Clear pending bit and wakeup anybody waiting to tear us down. - */ - clear_bit(BDI_pending, &bdi->state); - smp_mb__after_clear_bit(); - wake_up_bit(&bdi->state, BDI_pending); } return 0; |