> > diff --git a/arch/powerpc/platforms/cell/spufs/inode.c
> > b/arch/powerpc/platforms/cell/spufs/inode.c
> > index d4a094c..63b4e43 100644
> > --- a/arch/powerpc/platforms/cell/spufs/inode.c
> > +++ b/arch/powerpc/platforms/cell/spufs/inode.c
> > @@ -454,19 +454,16 @@ spufs_create_context(struct inode *inode, struct
> > dentry *dentry,
> > struct spu_gang *gang;
> > struct spu_context *neighbor;
> >
> > - ret = -EPERM;
> > if ((flags & SPU_CREATE_NOSCHED) &&
> > - !capable(CAP_SYS_NICE))
> > - goto out_unlock;
> > + !capable(CAP_SYa_NICE))
>
> ^typo
Odd, probably an emacs fart
> > + return -EPERM;
> >
> > - ret = -EINVAL;
> > if ((flags & (SPU_CREATE_NOSCHED | SPU_CREATE_ISOLATE))
> > == SPU_CREATE_ISOLATE)
> > - goto out_unlock;
> > + return -EINVAL;
> >
> > - ret = -ENODEV;
> > if ((flags & SPU_CREATE_ISOLATE) && !isolated_loader)
> > - goto out_unlock;
> > + return -ENODEV;
> >
> > gang = NULL;
> > neighbor = NULL;
>
> This mostly changes coding style, pointlessly.
How so ? it's no longer necessary to store ret and goto out since there
is no cleanup at all, which makes things smaller/simpler. I wouldn't
call that 'pointlessly'.
I tend to dislike the use of "goto xxxx" when the xxx: label does no
cleanup whatsoever.
> > @@ -512,10 +509,6 @@ spufs_create_context(struct inode *inode, struct
> > dentry *dentry,
> > out_aff_unlock:
> > if (affinity)
> > mutex_unlock(&gang->aff_mutex);
> > -out_unlock:
> > - mutex_unlock(&inode->i_mutex);
> > -out:
> > - dput(dentry);
> > return ret;
> > }
>
> The original intention of this was to always unlock in the error case. It
> seems that Al changed this in 1ba10681 "switch do_spufs_create() to
> user_path_create(), fix double-unlock" to never unlock early but always
> unlock in do_spu_create, fixing a different bug, but it looks like
> he forgot this one in the process.
>
> The reason why we originally had the unlock in the leaf functions is to
> avoid a problem with spu_forget(), which had to be called without
> the i_mutex held to avoid deadlocks.
Ok. I assumed it was fnotify that was the problem...
> > @@ -600,10 +591,6 @@ static int spufs_create_gang(struct inode *inode,
> > int err = simple_rmdir(inode, dentry);
> > WARN_ON(err);
> > }
> > -
> > -out:
> > - mutex_unlock(&inode->i_mutex);
> > - dput(dentry);
> > return ret;
> > }
>
> Right, this obviously goes together with the one above,
Yes, whatever they do they should do the same thing.
> > @@ -613,22 +600,21 @@ static struct file_system_type spufs_type;
> > long spufs_create(struct path *path, struct dentry *dentry
> > unsigned int flags, umode_t mode, struct file *filp)
> > {
> > - int ret;
> > + int ret = -EINVAL;
> >
> > - ret = -EINVAL;
> > /* check if we are on spufs */
> > if (path->dentry->d_sb->s_type != &spufs_type)
> > - goto out;
> > + goto fail;
> >
> > /* don't accept undefined flags */
> > if (flags & (~SPU_CREATE_FLAG_ALL))
> > - goto out;
> > + goto fail;
> >
> > /* only threads can be underneath a gang */
> > if (path->dentry != path->dentry->d_sb->s_root) {
> > if ((flags & SPU_CREATE_GANG) ||
> > !SPUFS_I(path->dentry->d_inode)->i_gang)
> > - goto out;
> > + goto fail;
> > }
> >
> > mode &= ~current_umask();
>
> These just change coding style, and not in a helpful way.
Oh I just renamed the label, it's helpful because the label is
specifically only for the fail case, not the general exit path, hence
"fail" is a better naming than "out". It's about code clarity.
> > @@ -640,12 +626,17 @@ long spufs_create(struct path *path, struct dentry
> > *dentry,
> > ret = spufs_create_context(path->dentry->d_inode,
> > dentry, path->mnt, flags, mode,
> > filp);
> > - if (ret >= 0)
> > + if (ret >= 0) {
> > + /* We drop these before fsnotify */
> > + mutex_unlock(&inode->i_mutex);
> > + dput(dentry);
> > fsnotify_mkdir(path->dentry->d_inode, dentry);
> > - return ret;
> >
> > -out:
> > - mutex_unlock(&path->dentry->d_inode->i_mutex);
> > + return ret;
> > + }
> > + fail:
> > + mutex_unlock(&inode->i_mutex);
> > + dput(dentry);
> > return ret;
> > }
> >
> > diff --git a/arch/powerpc/platforms/cell/spufs/syscalls.c
> > b/arch/powerpc/platforms/cell/spufs/syscalls.c
> > index 8591bb6..1a65ef2 100644
> > --- a/arch/powerpc/platforms/cell/spufs/syscalls.c
> > +++ b/arch/powerpc/platforms/cell/spufs/syscalls.c
> > @@ -70,11 +70,8 @@ static long do_spu_create(const char __user *pathname,
> > unsigned int flags,
> > ret = PTR_ERR(dentry);
> > if (!IS_ERR(dentry)) {
> > ret = spufs_create(&path, dentry, flags, mode, neighbor);
> > - mutex_unlock(&path.dentry->d_inode->i_mutex);
> > - dput(dentry);
> > path_put(&path);
> > }
> > -
> > return ret;
> > }
>
> This moves the unlock in front of the fsnotify_mkdir, where it was before Al's
> change. This seems independent of the other change.
No it's not, it all goes together. spufs_create_context() always
unlocked & dropped the dentry before returning, so I assumed the
lock had to be dropped before fsnotify.
Note that if the problem is that the lock has to be dropped before
spu_forget(), then we should indeed move it back into the leaf functions
and just remove all the unlock path from the top ones. It's a bit nasty
how we drop the mutex first, then do spu_forget, then drop the dentry
but we could go back to doing that.
What I want is consistent semantics. It's just silly to have 3 different
stacking levels which all 3 may or may not be responsible to dropping
the lock & dentry depending on circumstances.
In any case, what about this instead then:
diff --git a/arch/powerpc/platforms/cell/spufs/inode.c
b/arch/powerpc/platforms/cell/spufs/inode.c
index d4a094c..114ab14 100644
--- a/arch/powerpc/platforms/cell/spufs/inode.c
+++ b/arch/powerpc/platforms/cell/spufs/inode.c
@@ -646,6 +646,7 @@ long spufs_create(struct path *path, struct dentry *dentry,
out:
mutex_unlock(&path->dentry->d_inode->i_mutex);
+ dput(dentry);
return ret;
}
diff --git a/arch/powerpc/platforms/cell/spufs/syscalls.c
b/arch/powerpc/platforms/cell/spufs/syscalls.c
index 8591bb6..5665dcc 100644
--- a/arch/powerpc/platforms/cell/spufs/syscalls.c
+++ b/arch/powerpc/platforms/cell/spufs/syscalls.c
@@ -70,8 +70,6 @@ static long do_spu_create(const char __user *pathname,
unsigned int flags,
ret = PTR_ERR(dentry);
if (!IS_ERR(dentry)) {
ret = spufs_create(&path, dentry, flags, mode, neighbor);
- mutex_unlock(&path.dentry->d_inode->i_mutex);
- dput(dentry);
path_put(&path);
}
Cheers,
Ben.
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