linux-kernel - Re: [PATCH] cifs: set length when cifs_copy_pages_to

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Date:   Sat, 28 May 2022 18:31:30 -0500
From:   Steve French <smfrench@...il.com>
To:     Nick Desaulniers <ndesaulniers@...gle.com>
Cc:     Steve French <stfrench@...rosoft.com>,
        Nathan Chancellor <nathan@...nel.org>,
        David Howells <dhowells@...hat.com>,
        CIFS <linux-cifs@...r.kernel.org>,
        samba-technical <samba-technical@...ts.samba.org>,
        LKML <linux-kernel@...r.kernel.org>, llvm@...ts.linux.dev,
        Tom Rix <trix@...hat.com>, Steve French <sfrench@...ba.org>
Subject: Re: [PATCH] cifs: set length when cifs_copy_pages_to_iter is successful

Presumably this was in Dave Howell's patch set which we took out of
for-next to restructure in some of Al's feedback and some things found
during testing. So nothing to fix in current mainline or for-next ...
right?

On Sat, May 28, 2022 at 3:40 PM Nick Desaulniers
<ndesaulniers@...gle.com> wrote:
>
> + Steve's @microsoft.com email addr.
>
> On Thu, May 26, 2022 at 7:02 AM Tom Rix <trix@...hat.com> wrote:
> >
> > clang build fails with
> > fs/cifs/smb2ops.c:4984:7: error: variable 'length' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized]
> >   if (rdata->result != 0) {
> >       ^~~~~~~~~~~~~~~~~~
> >
> > handle_read_data() returns the number of bytes handled by setting the length variable.
> > This only happens in the copy_to_iter() branch, it needs to also happen in the
> > cifs_copy_pages_to_iter() branch.  When cifs_copy_pages_to_iter() is successful,
> > its parameter data_len is how many bytes were handled, so set length to data_len.
> >
> > Fixes: 67fd8cff2b0f ("cifs: Change the I/O paths to use an iterator rather than a page list")
> > Signed-off-by: Tom Rix <trix@...hat.com>
> > ---
> >  fs/cifs/smb2ops.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
> > index 3630e132781f..bfad482ec186 100644
> > --- a/fs/cifs/smb2ops.c
> > +++ b/fs/cifs/smb2ops.c
> > @@ -4988,7 +4988,7 @@ handle_read_data(struct TCP_Server_Info *server, struct mid_q_entry *mid,
> >                                 dequeue_mid(mid, rdata->result);
> >                         return 0;
> >                 }
> > -               rdata->got_bytes = pages_len;
> > +               length = rdata->got_bytes = pages_len;
> >
> >         } else if (buf_len >= data_offset + data_len) {
> >                 /* read response payload is in buf */
> > --
> > 2.27.0
> >
>
>
> --
> Thanks,
> ~Nick Desaulniers



-- 
Thanks,

Steve