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authorHannes Reinecke <hare@suse.de>2021-12-07 14:55:49 +0100
committerChristoph Hellwig <hch@lst.de>2021-12-23 11:22:45 +0100
commitf18ee3d988157ebcadc9b7e5fd34811938f50223 (patch)
tree35fa503aaf13484dc581ee2364cc8769d399fd79
parent3427f2b2c533d97bcc57b4237c2af21a8bd2cdbc (diff)
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: Hannes Reinecke <hare@suse.de> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
-rw-r--r--drivers/nvme/host/fabrics.c22
1 files changed, 21 insertions, 1 deletions
diff --git a/drivers/nvme/host/fabrics.c b/drivers/nvme/host/fabrics.c
index 282d54117e0a..7ae041e2b3fb 100644
--- a/drivers/nvme/host/fabrics.c
+++ b/drivers/nvme/host/fabrics.c
@@ -1069,6 +1069,26 @@ out_unlock:
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;
}