From cdb685cb9158fa67f6f4584ea39279ed7ae39253 Mon Sep 17 00:00:00 2001 From: Danil Kipnis Date: Thu, 21 May 2020 20:59:09 +0200 Subject: [PATCH] RDMA/rnbd: Fix compilation error when CONFIG_MODULES is disabled module_is_live function is only defined when CONFIG_MODULES is enabled. Use try_module_get instead to check whether the module is being removed. When module unload and manuall unmapping is happening in parallel, we can try removing the symlink twice: rnbd_client_exit vs. rnbd_clt_unmap_dev_store. This is probably not the best way to deal with this race in general, but for now this fixes the compilation issue when CONFIG_MODULES is disabled and has no functional impact. Regression tests passed. Fixes: 1eb54f8f5dd8 ("block/rnbd: client: sysfs interface functions") Link: https://lore.kernel.org/r/20200521185909.457245-1-danil.kipnis@cloud.ionos.com Reported-by: Randy Dunlap Suggested-by: Guoqing Jiang Signed-off-by: Danil Kipnis Acked-by: Randy Dunlap Signed-off-by: Jason Gunthorpe --- drivers/block/rnbd/rnbd-clt-sysfs.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/drivers/block/rnbd/rnbd-clt-sysfs.c b/drivers/block/rnbd/rnbd-clt-sysfs.c index a4508fc..4f4474e 100644 --- a/drivers/block/rnbd/rnbd-clt-sysfs.c +++ b/drivers/block/rnbd/rnbd-clt-sysfs.c @@ -428,12 +428,15 @@ static struct attribute *rnbd_dev_attrs[] = { void rnbd_clt_remove_dev_symlink(struct rnbd_clt_dev *dev) { /* - * The module_is_live() check is crucial and helps to avoid annoying - * sysfs warning raised in sysfs_remove_link(), when the whole sysfs - * path was just removed, see rnbd_close_sessions(). + * The module unload rnbd_client_exit path is racing with unmapping of + * the last single device from the sysfs manually + * i.e. rnbd_clt_unmap_dev_store() leading to a sysfs warning because + * of sysfs link already was removed already. */ - if (strlen(dev->blk_symlink_name) && module_is_live(THIS_MODULE)) + if (strlen(dev->blk_symlink_name) && try_module_get(THIS_MODULE)) { sysfs_remove_link(rnbd_devs_kobj, dev->blk_symlink_name); + module_put(THIS_MODULE); + } } static struct kobj_type rnbd_dev_ktype = { -- 2.7.4