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

Long Li
2017-08-21T18:18:59Z

> -----Original Message-----
> From: Leon Romanovsky [mailto:leon@kernel.org]
> Sent: Sunday, August 20, 2017 9:36 PM
> To: Long Li <longli@microsoft.com>
> Cc: Steve French <sfrench@samba.org>; linux-cifs@vger.kernel.org; samba-
> technical@lists.samba.org; linux-kernel@vger.kernel.org; linux-
> rdma@vger.kernel.org; Christoph Hellwig <hch@infradead.org>; Tom Talpey
> <ttalpey@microsoft.com>; Matthew Wilcox <mawilcox@microsoft.com>;
> Long Li <longli@microsoft.com>
> Subject: Re: [Patch v2 01/19] CIFS: Add RDMA mount option
>
> On Sun, Aug 20, 2017 at 12:04:25PM -0700, Long Li wrote:
> > From: Long Li <longli@microsoft.com>
> >
> > 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@microsoft.com>
> > ---
> > 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 for pointing it out. I will fix this.

>
> Thanks