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Subject: Re: [PATCH 5/9] vmw_balloon: remove the balloon-vmware file system
To:     Christoph Hellwig <hch@lst.de>, Al Viro <viro@zeniv.linux.org.uk>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Daniel Vetter <daniel@ffwll.ch>, Nadav Amit <namit@vmware.com>,
        "VMware, Inc." <pv-drivers@vmware.com>,
        "Michael S. Tsirkin" <mst@redhat.com>,
        Minchan Kim <minchan@kernel.org>,
        Nitin Gupta <ngupta@vflare.org>,
        Jason Gunthorpe <jgg@nvidia.com>,
        Alex Williamson <alex.williamson@redhat.com>,
        linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
        dri-devel@lists.freedesktop.org,
        virtualization@lists.linux-foundation.org,
        linux-fsdevel@vger.kernel.org, linux-mm@kvack.org
References: <20210309155348.974875-1-hch@lst.de>
 <20210309155348.974875-6-hch@lst.de>
From:   David Hildenbrand <david@redhat.com>
Organization: Red Hat GmbH
Message-ID: <8bdd6f30-3cd1-ad7f-df95-bbb85623ae64@redhat.com>
Date:   Tue, 9 Mar 2021 17:28:16 +0100
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On 09.03.21 16:53, Christoph Hellwig wrote:
> Just use the generic anon_inode file system.
> 
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>   drivers/misc/vmw_balloon.c | 24 ++----------------------
>   1 file changed, 2 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/misc/vmw_balloon.c b/drivers/misc/vmw_balloon.c
> index 5d057a05ddbee8..be4be32f858253 100644
> --- a/drivers/misc/vmw_balloon.c
> +++ b/drivers/misc/vmw_balloon.c
> @@ -16,6 +16,7 @@
>   //#define DEBUG
>   #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>   
> +#include <linux/anon_inodes.h>
>   #include <linux/types.h>
>   #include <linux/io.h>
>   #include <linux/kernel.h>
> @@ -1735,20 +1736,6 @@ static inline void vmballoon_debugfs_exit(struct vmballoon *b)
>   
>   
>   #ifdef CONFIG_BALLOON_COMPACTION
> -
> -static int vmballoon_init_fs_context(struct fs_context *fc)
> -{
> -	return init_pseudo(fc, BALLOON_VMW_MAGIC) ? 0 : -ENOMEM;
> -}
> -
> -static struct file_system_type vmballoon_fs = {
> -	.name           	= "balloon-vmware",
> -	.init_fs_context	= vmballoon_init_fs_context,
> -	.kill_sb        	= kill_anon_super,
> -};
> -
> -static struct vfsmount *vmballoon_mnt;
> -
>   /**
>    * vmballoon_migratepage() - migrates a balloon page.
>    * @b_dev_info: balloon device information descriptor.
> @@ -1878,8 +1865,6 @@ static void vmballoon_compaction_deinit(struct vmballoon *b)
>   		iput(b->b_dev_info.inode);
>   
>   	b->b_dev_info.inode = NULL;
> -	kern_unmount(vmballoon_mnt);
> -	vmballoon_mnt = NULL;
>   }
>   
>   /**
> @@ -1895,13 +1880,8 @@ static void vmballoon_compaction_deinit(struct vmballoon *b)
>    */
>   static __init int vmballoon_compaction_init(struct vmballoon *b)
>   {
> -	vmballoon_mnt = kern_mount(&vmballoon_fs);
> -	if (IS_ERR(vmballoon_mnt))
> -		return PTR_ERR(vmballoon_mnt);
> -
>   	b->b_dev_info.migratepage = vmballoon_migratepage;
> -	b->b_dev_info.inode = alloc_anon_inode_sb(vmballoon_mnt->mnt_sb);
> -
> +	b->b_dev_info.inode = alloc_anon_inode();
>   	if (IS_ERR(b->b_dev_info.inode))
>   		return PTR_ERR(b->b_dev_info.inode);
>   
> 

Same comment regarding BALLOON_VMW_MAGIC and includes (mount.h, 
pseudo_fs.h).

Apart from that looks good.

-- 
Thanks,

David / dhildenb