Re: [Patch v2 01/19] CIFS: Add RDMA mount option

[Leon Romanovsky <leon-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>]

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On Sun, Aug 20, 2017 at 12:04:25PM -0700, Long Li wrote:
> From: Long Li <longli-0li6OtcxBFHby3iVrkZq2A@public.gmane.org>
>
> Add "rdma" to CIFS mount option, which tells CIFS this is for connecting to a SMB server over SMBDirect. Add checks to validate this feature is only used on SMB 3.X dialects.
>
> To connect to SMBDirect, use "mount.cifs -o rdma,vers=3.x".
>
> Signed-off-by: Long Li <longli-0li6OtcxBFHby3iVrkZq2A@public.gmane.org>
> ---
>  fs/cifs/cifs_debug.c |  2 ++
>  fs/cifs/cifsfs.c     |  2 ++
>  fs/cifs/cifsglob.h   |  3 +++
>  fs/cifs/connect.c    | 25 ++++++++++++++++++++++++-
>  4 files changed, 31 insertions(+), 1 deletion(-)
>
> diff --git a/fs/cifs/cifs_debug.c b/fs/cifs/cifs_debug.c
> index 9727e1d..ba0870d 100644
> --- a/fs/cifs/cifs_debug.c
> +++ b/fs/cifs/cifs_debug.c
> @@ -171,6 +171,8 @@ static int cifs_debug_data_proc_show(struct seq_file *m, void *v)
>  				ses->ses_count, ses->serverOS, ses->serverNOS,
>  				ses->capabilities, ses->status);
>  			}
> +			if (server->rdma)
> +				seq_printf(m, "RDMA\n\t");
>  			seq_printf(m, "TCP status: %d\n\tLocal Users To "
>  				   "Server: %d SecMode: 0x%x Req On Wire: %d",
>  				   server->tcpStatus, server->srv_count,
> diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
> index fe0c8dc..a628800 100644
> --- a/fs/cifs/cifsfs.c
> +++ b/fs/cifs/cifsfs.c
> @@ -330,6 +330,8 @@ cifs_show_address(struct seq_file *s, struct TCP_Server_Info *server)
>  	default:
>  		seq_puts(s, "(unknown)");
>  	}
> +	if (server->rdma)
> +		seq_puts(s, ",rdma");
>  }
>
>  static void
> diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
> index 8289f95..703c2fb 100644
> --- a/fs/cifs/cifsglob.h
> +++ b/fs/cifs/cifsglob.h
> @@ -531,6 +531,7 @@ struct smb_vol {
>  	bool nopersistent:1;
>  	bool resilient:1; /* noresilient not required since not fored for CA */
>  	bool domainauto:1;
> +	bool rdma:1;
>  	unsigned int rsize;
>  	unsigned int wsize;
>  	bool sockopt_tcp_nodelay:1;
> @@ -649,6 +650,8 @@ struct TCP_Server_Info {
>  	bool	sec_kerberos;		/* supports plain Kerberos */
>  	bool	sec_mskerberos;		/* supports legacy MS Kerberos */
>  	bool	large_buf;		/* is current buffer large? */
> +	/* use SMBD connection instead of socket */
> +	bool	rdma;
>  	struct delayed_work	echo; /* echo ping workqueue job */
>  	char	*smallbuf;	/* pointer to current "small" buffer */
>  	char	*bigbuf;	/* pointer to current "big" buffer */
> diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
> index 2eeaac6..d5d0ecd 100644
> --- a/fs/cifs/connect.c
> +++ b/fs/cifs/connect.c
> @@ -94,7 +94,7 @@ enum {
>  	Opt_multiuser, Opt_sloppy, Opt_nosharesock,
>  	Opt_persistent, Opt_nopersistent,
>  	Opt_resilient, Opt_noresilient,
> -	Opt_domainauto,
> +	Opt_domainauto, Opt_rdma,
>
>  	/* Mount options which take numeric value */
>  	Opt_backupuid, Opt_backupgid, Opt_uid,
> @@ -185,6 +185,7 @@ static const match_table_t cifs_mount_option_tokens = {
>  	{ Opt_resilient, "resilienthandles"},
>  	{ Opt_noresilient, "noresilienthandles"},
>  	{ Opt_domainauto, "domainauto"},
> +	{ Opt_rdma, "rdma"},
>
>  	{ Opt_backupuid, "backupuid=%s" },
>  	{ Opt_backupgid, "backupgid=%s" },
> @@ -1541,6 +1542,9 @@ cifs_parse_mount_options(const char *mountdata, const char *devname,
>  		case Opt_domainauto:
>  			vol->domainauto = true;
>  			break;
> +		case Opt_rdma:
> +			vol->rdma = true;
> +			break;
>
>  		/* Numeric Values */
>  		case Opt_backupuid:
> @@ -1931,6 +1935,21 @@ cifs_parse_mount_options(const char *mountdata, const char *devname,
>  		goto cifs_parse_mount_err;
>  	}
>
> +	if (vol->rdma) {
> +		switch (vol->vals->protocol_id) {
> +		case SMB30_PROT_ID:
> +		case SMB302_PROT_ID:
> +		case SMB311_PROT_ID:
> +			break;

In cover letter, you wrote that this option is relevant for 3.X versions,
so why do you write explicitly versions and don't do check if (version > SMB30_PROT_ID) ...?

Thanks

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