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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Sasha Levin <sasha.levin@oracle.com>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Emil Karlson <jkarlson@tuxera.com>
Subject: [PATCH 4.4 147/230] fs/9p: use fscache mutex rather than spinlock
Date:   Fri, 22 Mar 2019 12:14:45 +0100
Message-Id: <20190322111246.959130531@linuxfoundation.org>
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4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Sasha Levin <sasha.levin@oracle.com>

commit 8f5fed1e917588f946ad8882bd47a4093db0ff4c upstream.

We may sleep inside a the lock, so use a mutex rather than spinlock.

Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: Emil Karlson <jkarlson@tuxera.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 fs/9p/cache.c     |    8 ++++----
 fs/9p/v9fs.h      |    2 +-
 fs/9p/vfs_inode.c |    2 +-
 3 files changed, 6 insertions(+), 6 deletions(-)

--- a/fs/9p/cache.c
+++ b/fs/9p/cache.c
@@ -243,14 +243,14 @@ void v9fs_cache_inode_set_cookie(struct
 	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(struc
 
 	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(struc
 	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)
--- 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;
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -244,7 +244,7 @@ struct inode *v9fs_alloc_inode(struct su
 		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;