Commit f18ee3d9 authored by Hannes Reinecke's avatar Hannes Reinecke Committed by Christoph Hellwig
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nvme-fabrics: print out valid arguments when reading from /dev/nvme-fabrics 



Currently applications have a hard time figuring out which
nvme-over-fabrics arguments are supported for any given kernel;
the ioctl will return an error code on failure, and the application
has to guess whether this was due to an invalid argument or due
to a connection or controller error.
With this patch applications can read a list of supported
arguments by simply reading from /dev/nvme-fabrics, allowing
them to validate the connection string.

Signed-off-by: default avatarHannes Reinecke <hare@suse.de>
Reviewed-by: default avatarChaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent 3427f2b2

drivers/nvme/host/fabrics.c

+21 −1
Original line number Diff line number Diff line
@@ -1069,6 +1069,26 @@ static ssize_t nvmf_dev_write(struct file *file, const char __user *ubuf, 
	return ret ? ret : count;

}



static void __nvmf_concat_opt_tokens(struct seq_file *seq_file)

{

	const struct match_token *tok;

	int idx;



	/*

	 * Add dummy entries for instance and cntlid to

	 * signal an invalid/non-existing controller

	 */

	seq_puts(seq_file, "instance=-1,cntlid=-1");

	for (idx = 0; idx < ARRAY_SIZE(opt_tokens); idx++) {

		tok = &opt_tokens[idx];

		if (tok->token == NVMF_OPT_ERR)

			continue;

		seq_puts(seq_file, ",");

		seq_puts(seq_file, tok->pattern);

	}

	seq_puts(seq_file, "\n");

}



static int nvmf_dev_show(struct seq_file *seq_file, void *private)

{

	struct nvme_ctrl *ctrl;
@@ -1077,7 +1097,7 @@ static int nvmf_dev_show(struct seq_file *seq_file, void *private) 
	mutex_lock(&nvmf_dev_mutex);

	ctrl = seq_file->private;

	if (!ctrl) {

		ret = -EINVAL;

		__nvmf_concat_opt_tokens(seq_file);

		goto out_unlock;

	}