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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: Sagi Grimberg <sagi@grimberg.me>,
	Chaitanya Kulkarni <Chaitanya.Kulkarni@wdc.com>,
	Stephen Bates <sbates@raithlin.com>, Jens Axboe <axboe@fb.com>,
	Keith Busch <kbusch@kernel.org>, Max Gurtovoy <maxg@mellanox.com>,
	Logan Gunthorpe <logang@deltatee.com>,
	Christoph Hellwig <hch@lst.de>
Subject: [PATCH v9 01/12] nvme-core: introduce nvme_ctrl_get_by_path()
Date: Wed,  9 Oct 2019 13:25:18 -0600
Message-ID: <20191009192530.13079-2-logang@deltatee.com> (raw)
In-Reply-To: <20191009192530.13079-1-logang@deltatee.com>

nvme_ctrl_get_by_path() is analagous to blkdev_get_by_path() except it
gets a struct nvme_ctrl from the path to its char dev (/dev/nvme0).
It makes use of filp_open() to open the file and uses the private
data to obtain a pointer to the struct nvme_ctrl. If the fops of the
file do not match, -EINVAL is returned.

The purpose of this function is to support NVMe-OF target passthru.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Max Gurtovoy <maxg@mellanox.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
---
 drivers/nvme/host/core.c | 24 ++++++++++++++++++++++++
 drivers/nvme/host/nvme.h |  2 ++
 2 files changed, 26 insertions(+)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index fd7dea36c3b6..30f9d91e25e3 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -2950,6 +2950,30 @@ static const struct file_operations nvme_dev_fops = {
 	.compat_ioctl	= nvme_dev_ioctl,
 };
 
+struct nvme_ctrl *nvme_ctrl_get_by_path(const char *path)
+{
+	struct nvme_ctrl *ctrl;
+	struct file *f;
+
+	f = filp_open(path, O_RDWR, 0);
+	if (IS_ERR(f))
+		return ERR_CAST(f);
+
+	if (f->f_op != &nvme_dev_fops) {
+		ctrl = ERR_PTR(-EINVAL);
+		goto out_close;
+	}
+
+	ctrl = f->private_data;
+	nvme_get_ctrl(ctrl);
+
+out_close:
+	filp_close(f, NULL);
+
+	return ctrl;
+}
+EXPORT_SYMBOL_GPL(nvme_ctrl_get_by_path);
+
 static ssize_t nvme_sysfs_reset(struct device *dev,
 				struct device_attribute *attr, const char *buf,
 				size_t count)
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index 38a83ef5bcd3..f83f990e409d 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -507,6 +507,8 @@ int nvme_get_log(struct nvme_ctrl *ctrl, u32 nsid, u8 log_page, u8 lsp,
 extern const struct attribute_group *nvme_ns_id_attr_groups[];
 extern const struct block_device_operations nvme_ns_head_ops;
 
+struct nvme_ctrl *nvme_ctrl_get_by_path(const char *path);
+
 #ifdef CONFIG_NVME_MULTIPATH
 static inline bool nvme_ctrl_use_ana(struct nvme_ctrl *ctrl)
 {
-- 
2.20.1


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  reply index

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-09 19:25 [PATCH v9 00/12] nvmet: add target passthru commands support Logan Gunthorpe
2019-10-09 19:25 ` Logan Gunthorpe [this message]
2019-10-09 22:13   ` [PATCH v9 01/12] nvme-core: introduce nvme_ctrl_get_by_path() Keith Busch
2019-10-10 11:37   ` Christoph Hellwig
2019-10-09 19:25 ` [PATCH v9 02/12] nvme-core: export existing ctrl and ns interfaces Logan Gunthorpe
2019-10-09 22:14   ` Keith Busch
2019-10-09 19:25 ` [PATCH v9 03/12] nvmet: add return value to nvmet_add_async_event() Logan Gunthorpe
2019-10-09 22:17   ` Keith Busch
2019-10-09 19:25 ` [PATCH v9 04/12] nvmet: make nvmet_copy_ns_identifier() non-static Logan Gunthorpe
2019-10-09 22:18   ` Keith Busch
2019-10-10 11:50   ` Christoph Hellwig
2019-10-09 19:25 ` [PATCH v9 05/12] Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> [logang@deltatee.com: fixed some of the wording in the help message] Signed-off-by: Logan Gunthorpe <logang@deltatee.com> Reviewed-by: Max Gurtovoy <maxg@mellanox.com> Logan Gunthorpe
2019-10-10 12:34   ` Christoph Hellwig
2019-10-25 23:09     ` [PATCH v9 05/12] Logan Gunthorpe
2019-10-09 19:25 ` [PATCH v9 05/12] nvmet-passthru: add passthru code to process commands Logan Gunthorpe
2019-10-09 19:25 ` [PATCH v9 06/12] nvmet-passthru: add enable/disable helpers Logan Gunthorpe
2019-10-09 19:25 ` [PATCH v9 07/12] nvmet-core: don't check the data len for pt-ctrl Logan Gunthorpe
2019-10-10 11:04   ` Christoph Hellwig
2019-10-09 19:25 ` [PATCH v9 08/12] nvmet-tcp: don't check data_len in nvmet_tcp_map_data() Logan Gunthorpe
2019-10-10 11:07   ` Christoph Hellwig
2019-10-09 19:25 ` [PATCH v9 09/12] nvmet-configfs: introduce passthru configfs interface Logan Gunthorpe
2019-10-09 19:25 ` [PATCH v9 10/12] block: don't check blk_rq_is_passthrough() in blk_do_io_stat() Logan Gunthorpe
2019-10-10 10:05   ` Christoph Hellwig
2019-10-10 17:56     ` Logan Gunthorpe
2019-10-09 19:25 ` [PATCH v9 11/12] block: call blk_account_io_start() in blk_execute_rq_nowait() Logan Gunthorpe
2019-10-10 10:06   ` Christoph Hellwig
2019-10-09 19:25 ` [PATCH v9 12/12] nvmet-passthru: support block accounting Logan Gunthorpe

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