From: Danil Kipnis <danil.kipnis@cloud.ionos.com>
To: linux-block@vger.kernel.org, linux-rdma@vger.kernel.org,
dledford@redhat.com, jgg@ziepe.ca, rdunlap@infradead.org
Cc: axboe@kernel.dk, bvanassche@acm.org, leon@kernel.org,
danil.kipnis@cloud.ionos.com, jinpu.wang@cloud.ionos.com,
guoqing.jiang@cloud.ionos.com
Subject: [PATCH] rnbd: fix compilation error when CONFIG_MODULES is disabled
Date: Thu, 21 May 2020 20:59:09 +0200 [thread overview]
Message-ID: <20200521185909.457245-1-danil.kipnis@cloud.ionos.com> (raw)
In-Reply-To: <ca0729a1-2e4d-670d-2519-a175b3035b28@infradead.org>
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")
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Suggested-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Signed-off-by: Danil Kipnis <danil.kipnis@cloud.ionos.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
---
v1->v2 Fix format of the "Fixes:" line
Add Acked-by Randy Runlap <rdunlap@infradead.org>
drivers/block/rnbd/rnbd-clt-sysfs.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/drivers/block/rnbd/rnbd-clt-sysfs.c b/drivers/block/rnbd/rnbd-clt-sysfs.c
index a4508fcc7ffe..73d7cb40abb3 100644
--- a/drivers/block/rnbd/rnbd-clt-sysfs.c
+++ b/drivers/block/rnbd/rnbd-clt-sysfs.c
@@ -428,12 +428,14 @@ 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 = {
--
2.25.1
next prev parent reply other threads:[~2020-05-21 18:59 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <86962843-e786-4a3f-0b85-1e06fbdbd76a@infradead.org>
2020-05-21 17:50 ` [PATCH] rnbd: fix compilation error when CONFIG_MODULES is disabled Danil Kipnis
2020-05-21 18:39 ` Randy Dunlap
2020-05-21 18:59 ` Danil Kipnis [this message]
2020-05-23 0:24 ` Jason Gunthorpe
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