Re: [SMBDIRECT][PATCH] missing rc checks while waiting for SMB3 over RDMA events

[Steve French <smfrench@gmail.com>]

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patch updated with Tom's suggestions - let me know if I have missed anything.


On Tue, Jun 22, 2021 at 10:18 AM Tom Talpey <tom@talpey.com> wrote:
>
> On 6/21/2021 5:32 PM, Steve French wrote:
> >      There were two places where we weren't checking for error
> >      (e.g. ERESTARTSYS) while waiting for rdma resolution.
> >
> >      Addresses-Coverity: 1462165 ("Unchecked return value")
> >     Signed-off-by: Steve French <stfrench@microsoft.com>
> >
> > diff --git a/fs/cifs/smbdirect.c b/fs/cifs/smbdirect.c
> > index 10dfe5006792..ae07732f750f 100644
> > --- a/fs/cifs/smbdirect.c
> > +++ b/fs/cifs/smbdirect.c
> > @@ -572,8 +572,11 @@ static struct rdma_cm_id *smbd_create_id(
> >                  log_rdma_event(ERR, "rdma_resolve_addr() failed %i\n", rc);
> >                  goto out;
> >          }
> > -       wait_for_completion_interruptible_timeout(
> > +       rc = wait_for_completion_interruptible_timeout(
> >                  &info->ri_done, msecs_to_jiffies(RDMA_RESOLVE_TIMEOUT));
> > +       /* -ERESTARTSYS, returned when interrupted, is the only rc mentioned */
>
> Suggest the same comment text as the one below, this one seems uncertain.
>
> > +       if (rc < 0)
> > +               goto out;
> >          rc = info->ri_rc;
> >          if (rc) {
> >                  log_rdma_event(ERR, "rdma_resolve_addr() completed %i\n", rc);
> > @@ -586,8 +589,10 @@ static struct rdma_cm_id *smbd_create_id(
> >                  log_rdma_event(ERR, "rdma_resolve_route() failed %i\n", rc);
> >                  goto out;
> >          }
> > -       wait_for_completion_interruptible_timeout(
> > +       rc = wait_for_completion_interruptible_timeout(
> >                  &info->ri_done, msecs_to_jiffies(RDMA_RESOLVE_TIMEOUT));
> > +       if (rc < 0)  /* e.g. if interrupted and returns -ERESTARTSYS */
>
> delete "and"?
>
> > +               goto out
>
> Missing a semicolon.     ^^^
>
> >          rc = info->ri_rc;
> >          if (rc) {
> >                  log_rdma_event(ERR, "rdma_resolve_route() completed %i\n", rc);
> >
> >
>
> One meta-comment. There's no message logged for these ERESTARTSYS cases.
> That might be confusing in the log, if they lead to failure.
>
> Reviewed-By: Tom Talpey <tom@talpey.com>
>
> Tom.



-- 
Thanks,

Steve

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From 0555b221528e9cb11f5766dcdee19c809187e42e Mon Sep 17 00:00:00 2001
From: Steve French <stfrench@microsoft.com>
Date: Mon, 21 Jun 2021 16:25:20 -0500
Subject: [PATCH] smbdirect: missing rc checks while waiting for rdma events

There were two places where we weren't checking for error
(e.g. ERESTARTSYS) while waiting for rdma resolution.

Addresses-Coverity: 1462165 ("Unchecked return value")
Reviewed-by: Tom Talpey <tom@talpey.com>
Reviewed-by: Long Li <longli@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
---
 fs/cifs/smbdirect.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/fs/cifs/smbdirect.c b/fs/cifs/smbdirect.c
index 10dfe5006792..31ef64eb7fbb 100644
--- a/fs/cifs/smbdirect.c
+++ b/fs/cifs/smbdirect.c
@@ -572,8 +572,13 @@ static struct rdma_cm_id *smbd_create_id(
 		log_rdma_event(ERR, "rdma_resolve_addr() failed %i\n", rc);
 		goto out;
 	}
-	wait_for_completion_interruptible_timeout(
+	rc = wait_for_completion_interruptible_timeout(
 		&info->ri_done, msecs_to_jiffies(RDMA_RESOLVE_TIMEOUT));
+	/* e.g. if interrupted returns -ERESTARTSYS */
+	if (rc < 0) {
+		log_rdma_event(ERR, "rdma_resolve_addr timeout rc: %i\n", rc);
+		goto out;
+	}
 	rc = info->ri_rc;
 	if (rc) {
 		log_rdma_event(ERR, "rdma_resolve_addr() completed %i\n", rc);
@@ -586,8 +591,13 @@ static struct rdma_cm_id *smbd_create_id(
 		log_rdma_event(ERR, "rdma_resolve_route() failed %i\n", rc);
 		goto out;
 	}
-	wait_for_completion_interruptible_timeout(
+	rc = wait_for_completion_interruptible_timeout(
 		&info->ri_done, msecs_to_jiffies(RDMA_RESOLVE_TIMEOUT));
+	/* e.g. if interrupted returns -ERESTARTSYS */
+	if (rc < 0)  {
+		log_rdma_event(ERR, "rdma_resolve_addr timeout rc: %i\n", rc);
+		goto out;
+	}
 	rc = info->ri_rc;
 	if (rc) {
 		log_rdma_event(ERR, "rdma_resolve_route() completed %i\n", rc);
-- 
2.30.2