From eb7ae5e06bb6e6ac6bb86872d27c43ebab92f6b2 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 4 May 2020 14:47:54 +0200 Subject: bdi: move bdi_dev_name out of line bdi_dev_name is not a fast path function, move it out of line. This prepares for using it from modular callers without having to export an implementation detail like bdi_unknown_name. Signed-off-by: Christoph Hellwig Reviewed-by: Jan Kara Reviewed-by: Greg Kroah-Hartman Reviewed-by: Bart Van Assche Signed-off-by: Jens Axboe --- mm/backing-dev.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) (limited to 'mm') diff --git a/mm/backing-dev.c b/mm/backing-dev.c index c81b4f3a7268..c2c44c89ee5d 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -21,7 +21,7 @@ struct backing_dev_info noop_backing_dev_info = { EXPORT_SYMBOL_GPL(noop_backing_dev_info); static struct class *bdi_class; -const char *bdi_unknown_name = "(unknown)"; +static const char *bdi_unknown_name = "(unknown)"; /* * bdi_lock protects bdi_tree and updates to bdi_list. bdi_list has RCU @@ -1043,6 +1043,14 @@ void bdi_put(struct backing_dev_info *bdi) } EXPORT_SYMBOL(bdi_put); +const char *bdi_dev_name(struct backing_dev_info *bdi) +{ + if (!bdi || !bdi->dev) + return bdi_unknown_name; + return dev_name(bdi->dev); +} +EXPORT_SYMBOL_GPL(bdi_dev_name); + static wait_queue_head_t congestion_wqh[2] = { __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[0]), __WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[1]) -- cgit From 6bd87eec23cbc9ed222bed0f5b5b02bf300e9a8d Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 4 May 2020 14:47:56 +0200 Subject: bdi: add a ->dev_name field to struct backing_dev_info Cache a copy of the name for the life time of the backing_dev_info structure so that we can reference it even after unregistering. Fixes: 68f23b89067f ("memcg: fix a crash in wb_workfn when a device disappears") Reported-by: Yufen Yu Signed-off-by: Christoph Hellwig Reviewed-by: Jan Kara Reviewed-by: Bart Van Assche Signed-off-by: Jens Axboe --- mm/backing-dev.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'mm') diff --git a/mm/backing-dev.c b/mm/backing-dev.c index c2c44c89ee5d..efc5b83acd2d 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -938,7 +938,8 @@ int bdi_register_va(struct backing_dev_info *bdi, const char *fmt, va_list args) if (bdi->dev) /* The driver needs to use separate queues per device */ return 0; - dev = device_create_vargs(bdi_class, NULL, MKDEV(0, 0), bdi, fmt, args); + vsnprintf(bdi->dev_name, sizeof(bdi->dev_name), fmt, args); + dev = device_create(bdi_class, NULL, MKDEV(0, 0), bdi, bdi->dev_name); if (IS_ERR(dev)) return PTR_ERR(dev); @@ -1047,7 +1048,7 @@ const char *bdi_dev_name(struct backing_dev_info *bdi) { if (!bdi || !bdi->dev) return bdi_unknown_name; - return dev_name(bdi->dev); + return bdi->dev_name; } EXPORT_SYMBOL_GPL(bdi_dev_name); -- cgit