From: Dan Williams <dan.j.williams@intel.com>
To: linux-cxl@vger.kernel.org
Cc: Jason Gunthorpe <jgg@nvidia.com>,
ira.weiny@intel.com, vishal.l.verma@intel.com,
alison.schofield@intel.com, linux-kernel@vger.kernel.org
Subject: [PATCH 2/4] cxl/mem: Fix cdev_device_add() error handling
Date: Wed, 24 Mar 2021 14:01:56 -0700 [thread overview]
Message-ID: <161661971651.1721612.7457823773061754064.stgit@dwillia2-desk3.amr.corp.intel.com> (raw)
In-Reply-To: <161661970558.1721612.10441826898835759137.stgit@dwillia2-desk3.amr.corp.intel.com>
If cdev_device_add() fails then the allocation performed by
dev_set_name() is leaked. Use put_device(), not open coded release, for
device_add() failures.
The comment is obsolete because direct err_id failures need not worry
about the device being live.
The release method expects the percpu_ref is already dead, so
percpu_ref_kill() is needed before put_device(). However, given that the
cdev was partially live wait_for_completion() also belongs in the
release method.
Fixes: b39cb1052a5c ("cxl/mem: Register CXL memX devices")
Reported-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
drivers/cxl/mem.c | 16 ++++++----------
1 file changed, 6 insertions(+), 10 deletions(-)
diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
index 30bf4f0f3c17..e53d573ae4ab 100644
--- a/drivers/cxl/mem.c
+++ b/drivers/cxl/mem.c
@@ -1049,6 +1049,7 @@ static void cxl_memdev_release(struct device *dev)
{
struct cxl_memdev *cxlmd = to_cxl_memdev(dev);
+ wait_for_completion(&cxlmd->ops_dead);
percpu_ref_exit(&cxlmd->ops_active);
ida_free(&cxl_memdev_ida, cxlmd->id);
kfree(cxlmd);
@@ -1157,7 +1158,6 @@ static void cxlmdev_unregister(void *_cxlmd)
percpu_ref_kill(&cxlmd->ops_active);
cdev_device_del(&cxlmd->cdev, dev);
- wait_for_completion(&cxlmd->ops_dead);
cxlmd->cxlm = NULL;
put_device(dev);
}
@@ -1210,20 +1210,16 @@ static int cxl_mem_add_memdev(struct cxl_mem *cxlm)
cdev_init(cdev, &cxl_memdev_fops);
rc = cdev_device_add(cdev, dev);
- if (rc)
- goto err_add;
+ if (rc) {
+ percpu_ref_kill(&cxlmd->ops_active);
+ put_device(dev);
+ return rc;
+ }
return devm_add_action_or_reset(dev->parent, cxlmdev_unregister, cxlmd);
-err_add:
- ida_free(&cxl_memdev_ida, cxlmd->id);
err_id:
- /*
- * Theoretically userspace could have already entered the fops,
- * so flush ops_active.
- */
percpu_ref_kill(&cxlmd->ops_active);
- wait_for_completion(&cxlmd->ops_dead);
percpu_ref_exit(&cxlmd->ops_active);
err_ref:
kfree(cxlmd);
next prev parent reply other threads:[~2021-03-24 21:02 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-24 21:01 [PATCH 0/4] cxl/mem: Fix memdev device setup Dan Williams
2021-03-24 21:01 ` [PATCH 1/4] cxl/mem: Use sysfs_emit() for attribute show routines Dan Williams
2021-03-25 16:49 ` Jason Gunthorpe
2021-03-24 21:01 ` Dan Williams [this message]
2021-03-25 17:11 ` [PATCH 2/4] cxl/mem: Fix cdev_device_add() error handling Jason Gunthorpe
2021-03-29 21:03 ` Dan Williams
2021-03-29 22:44 ` Jason Gunthorpe
2021-03-30 4:48 ` Dan Williams
2021-03-24 21:02 ` [PATCH 3/4] cxl/mem: Do not rely on device_add() side effects for dev_set_name() failures Dan Williams
2021-03-25 17:14 ` Jason Gunthorpe
2021-03-24 21:02 ` [PATCH 4/4] cxl/mem: Disable cxl device power management Dan Williams
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=161661971651.1721612.7457823773061754064.stgit@dwillia2-desk3.amr.corp.intel.com \
--to=dan.j.williams@intel.com \
--cc=alison.schofield@intel.com \
--cc=ira.weiny@intel.com \
--cc=jgg@nvidia.com \
--cc=linux-cxl@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=vishal.l.verma@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).