diff options
author | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-11-27 21:58:09 -0800 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-11-27 21:58:09 -0800 |
commit | 44c3eea650001d85f6adc951b6cd6f2e6fe7a155 (patch) | |
tree | e8a30bec684aba03ae027e428ce6cbd721a6051a /fs | |
parent | 5d60418e54751c856f5aecc308620fde9572e481 (diff) | |
parent | 81440e73744446adbe5b5d1f19460203d275028f (diff) |
Merge branch 'driver-core-linus' into driver-core-next
We need those sysfs fixes in this branch to make testing, and future
patches apply properly.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs')
-rw-r--r-- | fs/sysfs/file.c | 22 |
1 files changed, 20 insertions, 2 deletions
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c index 564abd201af..0f3f0a252a5 100644 --- a/fs/sysfs/file.c +++ b/fs/sysfs/file.c @@ -609,7 +609,7 @@ static int sysfs_open_file(struct inode *inode, struct file *file) struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata; struct kobject *kobj = attr_sd->s_parent->s_dir.kobj; struct sysfs_open_file *of; - bool has_read, has_write; + bool has_read, has_write, has_mmap; int error = -EACCES; /* need attr_sd for attr and ops, its parent for kobj */ @@ -621,6 +621,7 @@ static int sysfs_open_file(struct inode *inode, struct file *file) has_read = battr->read || battr->mmap; has_write = battr->write || battr->mmap; + has_mmap = battr->mmap; } else { const struct sysfs_ops *ops = sysfs_file_ops(attr_sd); @@ -632,6 +633,7 @@ static int sysfs_open_file(struct inode *inode, struct file *file) has_read = ops->show; has_write = ops->store; + has_mmap = false; } /* check perms and supported operations */ @@ -649,7 +651,23 @@ static int sysfs_open_file(struct inode *inode, struct file *file) if (!of) goto err_out; - mutex_init(&of->mutex); + /* + * The following is done to give a different lockdep key to + * @of->mutex for files which implement mmap. This is a rather + * crude way to avoid false positive lockdep warning around + * mm->mmap_sem - mmap nests @of->mutex under mm->mmap_sem and + * reading /sys/block/sda/trace/act_mask grabs sr_mutex, under + * which mm->mmap_sem nests, while holding @of->mutex. As each + * open file has a separate mutex, it's okay as long as those don't + * happen on the same file. At this point, we can't easily give + * each file a separate locking class. Let's differentiate on + * whether the file has mmap or not for now. + */ + if (has_mmap) + mutex_init(&of->mutex); + else + mutex_init(&of->mutex); + of->sd = attr_sd; of->file = file; |