From 91d68905aee08a79b9ba82676c834fc670d722a0 Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Mon, 10 Apr 2017 16:13:15 -0600 Subject: [PATCH] blk-mq: Export queue state through /sys/kernel/debug/block/*/state Make it possible to check whether or not a block layer queue has been stopped. Make it possible to start and to run a blk-mq queue from user space. Signed-off-by: Bart Van Assche Cc: Omar Sandoval Cc: Hannes Reinecke Signed-off-by: Jens Axboe --- block/blk-mq-debugfs.c | 106 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 106 insertions(+) diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c index 4b3f962a9c7a..b25c76a0cbbc 100644 --- a/block/blk-mq-debugfs.c +++ b/block/blk-mq-debugfs.c @@ -43,6 +43,109 @@ static int blk_mq_debugfs_seq_open(struct inode *inode, struct file *file, return ret; } +static int blk_flags_show(struct seq_file *m, const unsigned long flags, + const char *const *flag_name, int flag_name_count) +{ + bool sep = false; + int i; + + for (i = 0; i < sizeof(flags) * BITS_PER_BYTE; i++) { + if (!(flags & BIT(i))) + continue; + if (sep) + seq_puts(m, " "); + sep = true; + if (i < flag_name_count && flag_name[i]) + seq_puts(m, flag_name[i]); + else + seq_printf(m, "%d", i); + } + seq_puts(m, "\n"); + return 0; +} + +static const char *const blk_queue_flag_name[] = { + [QUEUE_FLAG_QUEUED] = "QUEUED", + [QUEUE_FLAG_STOPPED] = "STOPPED", + [QUEUE_FLAG_SYNCFULL] = "SYNCFULL", + [QUEUE_FLAG_ASYNCFULL] = "ASYNCFULL", + [QUEUE_FLAG_DYING] = "DYING", + [QUEUE_FLAG_BYPASS] = "BYPASS", + [QUEUE_FLAG_BIDI] = "BIDI", + [QUEUE_FLAG_NOMERGES] = "NOMERGES", + [QUEUE_FLAG_SAME_COMP] = "SAME_COMP", + [QUEUE_FLAG_FAIL_IO] = "FAIL_IO", + [QUEUE_FLAG_STACKABLE] = "STACKABLE", + [QUEUE_FLAG_NONROT] = "NONROT", + [QUEUE_FLAG_IO_STAT] = "IO_STAT", + [QUEUE_FLAG_DISCARD] = "DISCARD", + [QUEUE_FLAG_NOXMERGES] = "NOXMERGES", + [QUEUE_FLAG_ADD_RANDOM] = "ADD_RANDOM", + [QUEUE_FLAG_SECERASE] = "SECERASE", + [QUEUE_FLAG_SAME_FORCE] = "SAME_FORCE", + [QUEUE_FLAG_DEAD] = "DEAD", + [QUEUE_FLAG_INIT_DONE] = "INIT_DONE", + [QUEUE_FLAG_NO_SG_MERGE] = "NO_SG_MERGE", + [QUEUE_FLAG_POLL] = "POLL", + [QUEUE_FLAG_WC] = "WC", + [QUEUE_FLAG_FUA] = "FUA", + [QUEUE_FLAG_FLUSH_NQ] = "FLUSH_NQ", + [QUEUE_FLAG_DAX] = "DAX", + [QUEUE_FLAG_STATS] = "STATS", + [QUEUE_FLAG_POLL_STATS] = "POLL_STATS", + [QUEUE_FLAG_REGISTERED] = "REGISTERED", +}; + +static int blk_queue_flags_show(struct seq_file *m, void *v) +{ + struct request_queue *q = m->private; + + blk_flags_show(m, q->queue_flags, blk_queue_flag_name, + ARRAY_SIZE(blk_queue_flag_name)); + return 0; +} + +static ssize_t blk_queue_flags_store(struct file *file, const char __user *ubuf, + size_t len, loff_t *offp) +{ + struct request_queue *q = file_inode(file)->i_private; + char op[16] = { }, *s; + + len = min(len, sizeof(op) - 1); + if (copy_from_user(op, ubuf, len)) + return -EFAULT; + s = op; + strsep(&s, " \t\n"); /* strip trailing whitespace */ + if (strcmp(op, "run") == 0) { + blk_mq_run_hw_queues(q, true); + } else if (strcmp(op, "start") == 0) { + blk_mq_start_stopped_hw_queues(q, true); + } else { + pr_err("%s: unsupported operation %s. Use either 'run' or 'start'\n", + __func__, op); + return -EINVAL; + } + return len; +} + +static int blk_queue_flags_open(struct inode *inode, struct file *file) +{ + return single_open(file, blk_queue_flags_show, inode->i_private); +} + +static const struct file_operations blk_queue_flags_fops = { + .open = blk_queue_flags_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, + .write = blk_queue_flags_store, +}; + +static const struct blk_mq_debugfs_attr blk_queue_attrs[] = { + {"state", 0600, &blk_queue_flags_fops}, + {}, +}; + static void print_stat(struct seq_file *m, struct blk_rq_stat *stat) { if (stat->nr_samples) { @@ -735,6 +838,9 @@ int blk_mq_debugfs_register_hctxs(struct request_queue *q) if (!q->debugfs_dir) return -ENOENT; + if (!debugfs_create_files(q->debugfs_dir, q, blk_queue_attrs)) + goto err; + q->mq_debugfs_dir = debugfs_create_dir("mq", q->debugfs_dir); if (!q->mq_debugfs_dir) goto err; -- 2.30.2