From: Logan Gunthorpe <logang@deltatee.com>
To: linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org,
linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org
Cc: Christoph Hellwig <hch@lst.de>, Sagi Grimberg <sagi@grimberg.me>,
Keith Busch <kbusch@kernel.org>, Jens Axboe <axboe@fb.com>,
Chaitanya Kulkarni <Chaitanya.Kulkarni@wdc.com>,
Max Gurtovoy <maxg@mellanox.com>,
Stephen Bates <sbates@raithlin.com>,
Logan Gunthorpe <logang@deltatee.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Alexander Viro <viro@zeniv.linux.org.uk>
Subject: [PATCH v6 02/16] chardev: introduce cdev_get_by_path()
Date: Thu, 25 Jul 2019 11:23:21 -0600 [thread overview]
Message-ID: <20190725172335.6825-3-logang@deltatee.com> (raw)
In-Reply-To: <20190725172335.6825-1-logang@deltatee.com>
cdev_get_by_path() attempts to retrieve a struct cdev from
a path name. It is analagous to blkdev_get_by_path().
This will be necessary to create a nvme_ctrl_get_by_path()to
support NVMe-OF passthru.
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
---
fs/char_dev.c | 34 ++++++++++++++++++++++++++++++++++
include/linux/cdev.h | 1 +
2 files changed, 35 insertions(+)
diff --git a/fs/char_dev.c b/fs/char_dev.c
index 5cc53bd5f654..25037d642ff8 100644
--- a/fs/char_dev.c
+++ b/fs/char_dev.c
@@ -22,6 +22,7 @@
#include <linux/mutex.h>
#include <linux/backing-dev.h>
#include <linux/tty.h>
+#include <linux/namei.h>
#include "internal.h"
@@ -403,6 +404,38 @@ static struct cdev *cdev_lookup(struct inode *inode)
return p;
}
+struct cdev *cdev_get_by_path(const char *pathname)
+{
+ struct inode *inode;
+ struct cdev *cdev;
+ struct path path;
+ int error;
+
+ if (!pathname || !*pathname)
+ return ERR_PTR(-EINVAL);
+
+ error = kern_path(pathname, LOOKUP_FOLLOW, &path);
+ if (error)
+ return ERR_PTR(error);
+
+ if (!may_open_dev(&path)) {
+ cdev = ERR_PTR(-EACCES);
+ goto out;
+ }
+
+ inode = d_backing_inode(path.dentry);
+ if (!S_ISCHR(inode->i_mode)) {
+ cdev = ERR_PTR(-EINVAL);
+ goto out;
+ }
+
+ cdev = cdev_lookup(inode);
+
+out:
+ path_put(&path);
+ return cdev;
+}
+
/*
* Called every time a character special file is opened
*/
@@ -690,5 +723,6 @@ EXPORT_SYMBOL(cdev_add);
EXPORT_SYMBOL(cdev_set_parent);
EXPORT_SYMBOL(cdev_device_add);
EXPORT_SYMBOL(cdev_device_del);
+EXPORT_SYMBOL(cdev_get_by_path);
EXPORT_SYMBOL(__register_chrdev);
EXPORT_SYMBOL(__unregister_chrdev);
diff --git a/include/linux/cdev.h b/include/linux/cdev.h
index 0e8cd6293deb..c7f2df2ca69a 100644
--- a/include/linux/cdev.h
+++ b/include/linux/cdev.h
@@ -24,6 +24,7 @@ void cdev_init(struct cdev *, const struct file_operations *);
struct cdev *cdev_alloc(void);
+struct cdev *cdev_get_by_path(const char *pathname);
void cdev_put(struct cdev *p);
int cdev_add(struct cdev *, dev_t, unsigned);
--
2.20.1
next prev parent reply other threads:[~2019-07-25 17:23 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-25 17:23 [PATCH v6 00/16] nvmet: add target passthru commands support Logan Gunthorpe
2019-07-25 17:23 ` [PATCH v6 01/16] chardev: factor out cdev_lookup() helper Logan Gunthorpe
2019-07-25 17:23 ` Logan Gunthorpe [this message]
2019-07-25 17:40 ` [PATCH v6 02/16] chardev: introduce cdev_get_by_path() Greg Kroah-Hartman
2019-07-25 17:53 ` Logan Gunthorpe
2019-07-25 17:58 ` Matthew Wilcox
2019-07-25 18:08 ` Logan Gunthorpe
2019-07-25 18:08 ` Greg Kroah-Hartman
2019-07-25 18:14 ` Logan Gunthorpe
2019-07-25 18:27 ` Greg Kroah-Hartman
2019-07-25 18:36 ` Logan Gunthorpe
2019-07-25 19:02 ` Sagi Grimberg
2019-07-25 19:34 ` Greg Kroah-Hartman
2019-07-25 19:37 ` Sagi Grimberg
2019-07-25 19:43 ` Greg Kroah-Hartman
2019-07-25 19:45 ` Sagi Grimberg
2019-07-25 19:43 ` Sagi Grimberg
2019-07-25 19:41 ` Logan Gunthorpe
2019-07-25 19:00 ` Matthew Wilcox
2019-07-25 19:05 ` Sagi Grimberg
2019-07-25 19:11 ` Matthew Wilcox
2019-07-25 19:24 ` Logan Gunthorpe
2019-07-25 19:26 ` Matthew Wilcox
2019-07-25 19:31 ` Logan Gunthorpe
2019-07-25 23:55 ` Al Viro
2019-07-26 4:29 ` Sagi Grimberg
2019-07-26 7:13 ` Greg Kroah-Hartman
2019-07-26 15:46 ` Logan Gunthorpe
2019-07-25 19:31 ` Sagi Grimberg
2019-07-25 18:10 ` Greg Kroah-Hartman
2019-07-25 18:16 ` Logan Gunthorpe
2019-07-25 17:23 ` [PATCH v6 03/16] chardev: export cdev_put() Logan Gunthorpe
2019-07-25 17:23 ` [PATCH v6 04/16] nvme-core: introduce nvme_get_by_path() Logan Gunthorpe
2019-07-25 17:50 ` Matthew Wilcox
2019-07-25 17:54 ` Logan Gunthorpe
2019-07-25 19:58 ` Keith Busch
2019-07-25 20:12 ` Sagi Grimberg
2019-07-25 20:28 ` Logan Gunthorpe
2019-07-25 20:31 ` Keith Busch
2019-07-25 20:37 ` Logan Gunthorpe
2019-07-25 17:23 ` [PATCH v6 05/16] nvme-core: export existing ctrl and ns interfaces Logan Gunthorpe
2019-07-25 17:23 ` [PATCH v6 06/16] nvmet: add return value to nvmet_add_async_event() Logan Gunthorpe
2019-07-25 17:23 ` [PATCH v6 07/16] nvmet: make nvmet_copy_ns_identifier() non-static Logan Gunthorpe
2019-07-25 17:23 ` [PATCH v6 08/16] nvmet-passthru: update KConfig with config passthru option Logan Gunthorpe
2019-07-25 17:23 ` [PATCH v6 09/16] nvmet-passthru: add passthru code to process commands Logan Gunthorpe
2019-07-25 17:23 ` [PATCH v6 10/16] nvmet-passthru: add enable/disable helpers Logan Gunthorpe
2019-07-25 17:23 ` [PATCH v6 11/16] nvmet-core: allow one host per passthru-ctrl Logan Gunthorpe
2019-07-25 17:23 ` [PATCH v6 12/16] nvmet-core: don't check the data len for pt-ctrl Logan Gunthorpe
2019-07-25 17:23 ` [PATCH v6 13/16] nvmet-configfs: introduce passthru configfs interface Logan Gunthorpe
2019-07-25 17:23 ` [PATCH v6 14/16] block: don't check blk_rq_is_passthrough() in blk_do_io_stat() Logan Gunthorpe
2019-07-25 17:23 ` [PATCH v6 15/16] block: call blk_account_io_start() in blk_execute_rq_nowait() Logan Gunthorpe
2019-07-25 17:23 ` [PATCH v6 16/16] nvmet-passthru: support block accounting Logan Gunthorpe
2019-07-26 6:23 ` [PATCH v6 00/16] nvmet: add target passthru commands support Hannes Reinecke
2019-07-26 17:07 ` Logan Gunthorpe
2019-07-26 22:21 ` Sagi Grimberg
2019-07-26 22:37 ` Logan Gunthorpe
2019-07-26 23:13 ` Sagi Grimberg
2019-07-27 0:09 ` Logan Gunthorpe
2019-07-27 0:50 ` Stephen Bates
2019-07-29 16:15 ` Sagi Grimberg
2019-07-29 16:17 ` Logan Gunthorpe
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