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author | Linus Torvalds <torvalds@linux-foundation.org> | 2013-11-28 06:04:37 +0100 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-11-28 06:04:37 +0100 |
commit | f496863658eac9054d4bd4c661774d76d83255e0 (patch) | |
tree | 897e967416a204e21d957386514559b2a07a2a9d /fs | |
parent | Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jik... (diff) | |
parent | Revert "sysfs: handle duplicate removal attempts in sysfs_remove_group()" (diff) | |
download | linux-f496863658eac9054d4bd4c661774d76d83255e0.tar.xz linux-f496863658eac9054d4bd4c661774d76d83255e0.zip |
Merge tag 'driver-core-3.13-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core
Pull driver core fixes from Greg KH:
"Here are 3 patches for sysfs issues that have been reported. Well, 1
patch really, the first one is reverted as it's not really needed (the
correct fix is coming in through the different driver subsystems
instead)
But that 1 sysfs fix is needed, so this is still a good thing to pull
in now"
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* tag 'driver-core-3.13-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
Revert "sysfs: handle duplicate removal attempts in sysfs_remove_group()"
sysfs: use a separate locking class for open files depending on mmap
sysfs: handle duplicate removal attempts in sysfs_remove_group()
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 79b5da2acbe1..b94f93685093 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; |