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Merge branch 'driver-core-linus' into driver-core-next

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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>
This commit is contained in:
Greg Kroah-Hartman 2013-11-27 21:58:09 -08:00
commit 44c3eea650
1 changed files with 20 additions and 2 deletions
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22
fs/sysfs/file.c
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@ -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;