Re: [PATCH] staging: erofs: using switch-case while checking the inode type.

[Gao Xiang <gaoxiang25@huawei.com>]

On Thu, Aug 29, 2019 at 07:35:01PM +0530, Pratik Shinde wrote:
> Hi Gao,
> 
> Sorry I didn't pull the latest tree. I will do the necessary.
> Anyways, don't you think it will be cleaner to have a switch case statement
> rather than if-else statement.

I think so, but that's another personal choise and no urgent
as well (It is just a cleanup to some extent).

I am very happy that you send a patch about this, but we have
to take care of handling "fall through" properly at least,
and I don't want to introduce some extra compile warnings
instead at this time.

EROFS is sensitive for now and I have no idea what the "real"
point is.

Thanks,
Gao Xiang

> 
> --Pratik
> 
> 
> 
> On Thu, 29 Aug, 2019, 7:27 PM Gao Xiang, <gaoxiang25@huawei.com> wrote:
> 
> > Hi Pratik,
> >
> > On Thu, Aug 29, 2019 at 06:38:13PM +0530, Pratik Shinde wrote:
> > > while filling the linux inode, using switch-case statement to check
> > > the type of inode.
> > > switch-case statement looks more clean.
> > >
> > > Signed-off-by: Pratik Shinde <pratikshinde320@gmail.com>
> >
> > No, that is not the case, see __ext4_iget() in fs/ext4/inode.c.
> > and could you write patches based on latest staging tree?
> > erofs is now in "fs/" rather than "drivers/staging".
> > and I will review it then.
> >
> > p.s. if someone argues here or there, there will be endless
> > issues since there is no standard at all.
> >
> > Thanks,
> > Gao Xiang
> >
> > > ---
> > >  drivers/staging/erofs/inode.c | 18 ++++++++++++------
> > >  1 file changed, 12 insertions(+), 6 deletions(-)
> > >
> > > diff --git a/drivers/staging/erofs/inode.c
> > b/drivers/staging/erofs/inode.c
> > > index 4c3d8bf..2d2d545 100644
> > > --- a/drivers/staging/erofs/inode.c
> > > +++ b/drivers/staging/erofs/inode.c
> > > @@ -190,22 +190,28 @@ static int fill_inode(struct inode *inode, int
> > isdir)
> > >       err = read_inode(inode, data + ofs);
> > >       if (!err) {
> > >               /* setup the new inode */
> > > -             if (S_ISREG(inode->i_mode)) {
> > > +             switch (inode->i_mode & S_IFMT) {
> > > +             case S_IFREG:
> > >                       inode->i_op = &erofs_generic_iops;
> > >                       inode->i_fop = &generic_ro_fops;
> > > -             } else if (S_ISDIR(inode->i_mode)) {
> > > +                     break;
> > > +             case S_IFDIR:
> > >                       inode->i_op = &erofs_dir_iops;
> > >                       inode->i_fop = &erofs_dir_fops;
> > > -             } else if (S_ISLNK(inode->i_mode)) {
> > > +                     break;
> > > +             case S_IFLNK:
> > >                       /* by default, page_get_link is used for symlink */
> > >                       inode->i_op = &erofs_symlink_iops;
> > >                       inode_nohighmem(inode);
> > > -             } else if (S_ISCHR(inode->i_mode) ||
> > S_ISBLK(inode->i_mode) ||
> > > -                     S_ISFIFO(inode->i_mode) ||
> > S_ISSOCK(inode->i_mode)) {
> > > +                     break;
> > > +             case S_IFCHR:
> > > +             case S_IFBLK:
> > > +             case S_IFIFO:
> > > +             case S_IFSOCK:
> > >                       inode->i_op = &erofs_generic_iops;
> > >                       init_special_inode(inode, inode->i_mode,
> > inode->i_rdev);
> > >                       goto out_unlock;
> > > -             } else {
> > > +             default:
> > >                       err = -EIO;
> > >                       goto out_unlock;
> > >               }
> > > --
> > > 2.9.3
> > >
> >