linux-kernel - Re: [PATCH] fs/9p: use fscache mutex rather than spinlock

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Message-ID: <568EEB8F.3020606@oracle.com>
Date:	Thu, 7 Jan 2016 17:49:51 -0500
From:	Sasha Levin <sasha.levin@...cle.com>
To:	ericvh@...il.com, rminnich@...dia.gov, lucho@...kov.net
Cc:	v9fs-developer@...ts.sourceforge.net, linux-kernel@...r.kernel.org,
	Al Viro <viro@...IV.linux.org.uk>
Subject: Re: [PATCH] fs/9p: use fscache mutex rather than spinlock

Ping?

On 11/09/2015 04:06 PM, Sasha Levin wrote:
> We may sleep inside a the lock, so use a mutex rather than spinlock.
> 
> Signed-off-by: Sasha Levin <sasha.levin@...cle.com>
> ---
>  fs/9p/cache.c     |    8 ++++----
>  fs/9p/v9fs.h      |    2 +-
>  fs/9p/vfs_inode.c |    2 +-
>  3 files changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/fs/9p/cache.c b/fs/9p/cache.c
> index a69260f..103ca5e 100644
> --- a/fs/9p/cache.c
> +++ b/fs/9p/cache.c
> @@ -243,14 +243,14 @@ void v9fs_cache_inode_set_cookie(struct inode *inode, struct file *filp)
>  	if (!v9inode->fscache)
>  		return;
>  
> -	spin_lock(&v9inode->fscache_lock);
> +	mutex_lock(&v9inode->fscache_lock);
>  
>  	if ((filp->f_flags & O_ACCMODE) != O_RDONLY)
>  		v9fs_cache_inode_flush_cookie(inode);
>  	else
>  		v9fs_cache_inode_get_cookie(inode);
>  
> -	spin_unlock(&v9inode->fscache_lock);
> +	mutex_unlock(&v9inode->fscache_lock);
>  }
>  
>  void v9fs_cache_inode_reset_cookie(struct inode *inode)
> @@ -264,7 +264,7 @@ void v9fs_cache_inode_reset_cookie(struct inode *inode)
>  
>  	old = v9inode->fscache;
>  
> -	spin_lock(&v9inode->fscache_lock);
> +	mutex_lock(&v9inode->fscache_lock);
>  	fscache_relinquish_cookie(v9inode->fscache, 1);
>  
>  	v9ses = v9fs_inode2v9ses(inode);
> @@ -274,7 +274,7 @@ void v9fs_cache_inode_reset_cookie(struct inode *inode)
>  	p9_debug(P9_DEBUG_FSC, "inode %p revalidating cookie old %p new %p\n",
>  		 inode, old, v9inode->fscache);
>  
> -	spin_unlock(&v9inode->fscache_lock);
> +	mutex_unlock(&v9inode->fscache_lock);
>  }
>  
>  int __v9fs_fscache_release_page(struct page *page, gfp_t gfp)
> diff --git a/fs/9p/v9fs.h b/fs/9p/v9fs.h
> index 0923f2c..6877050 100644
> --- a/fs/9p/v9fs.h
> +++ b/fs/9p/v9fs.h
> @@ -123,7 +123,7 @@ struct v9fs_session_info {
>  
>  struct v9fs_inode {
>  #ifdef CONFIG_9P_FSCACHE
> -	spinlock_t fscache_lock;
> +	struct mutex fscache_lock;
>  	struct fscache_cookie *fscache;
>  #endif
>  	struct p9_qid qid;
> diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
> index 699941e..b0358db 100644
> --- a/fs/9p/vfs_inode.c
> +++ b/fs/9p/vfs_inode.c
> @@ -244,7 +244,7 @@ struct inode *v9fs_alloc_inode(struct super_block *sb)
>  		return NULL;
>  #ifdef CONFIG_9P_FSCACHE
>  	v9inode->fscache = NULL;
> -	spin_lock_init(&v9inode->fscache_lock);
> +	mutex_init(&v9inode->fscache_lock);
>  #endif
>  	v9inode->writeback_fid = NULL;
>  	v9inode->cache_validity = 0;
>