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| author | Alan Stern <stern@rowland.harvard.edu> | 2007-03-15 15:51:28 -0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-03-15 15:29:26 -0700 |
| commit | e7b0d26a86943370c04d6833c6edba2a72a6e240 (patch) | |
| tree | 696e696176a1e72abb80afa6112fc057b39bf86b /fs/sysfs | |
| parent | d9a9cdfb078d755e648d53ec25b7370f84ee5729 (diff) | |
| download | lwn-e7b0d26a86943370c04d6833c6edba2a72a6e240.tar.gz lwn-e7b0d26a86943370c04d6833c6edba2a72a6e240.zip | |
[PATCH] sysfs: reinstate exclusion between method calls and attribute unregistration
This patch (as869) reinstates the mutual exclusion between sysfs
attribute method calls and attribute unregistration. The
previously-reported deadlocks have been fixed, and this exclusion is
by far the simplest way to avoid races during driver unbinding.
The check for orphaned read-buffers has been moved down slightly, so
that the remainder of a partially-read buffer will still be available
to userspace even after the attribute has been unregistered.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/sysfs')
| -rw-r--r-- | fs/sysfs/file.c | 10 | ||||
| -rw-r--r-- | fs/sysfs/inode.c | 10 |
2 files changed, 12 insertions, 8 deletions
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c index 1bafdf6e171c..fc4633378dc0 100644 --- a/fs/sysfs/file.c +++ b/fs/sysfs/file.c @@ -168,12 +168,12 @@ sysfs_read_file(struct file *file, char __user *buf, size_t count, loff_t *ppos) ssize_t retval = 0; down(&buffer->sem); - if (buffer->orphaned) { - retval = -ENODEV; - goto out; - } if (buffer->needs_read_fill) { - if ((retval = fill_read_buffer(file->f_path.dentry,buffer))) + if (buffer->orphaned) + retval = -ENODEV; + else + retval = fill_read_buffer(file->f_path.dentry,buffer); + if (retval) goto out; } pr_debug("%s: count = %zd, ppos = %lld, buf = %s\n", diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c index ccb7d722c558..4de5c6b89918 100644 --- a/fs/sysfs/inode.c +++ b/fs/sysfs/inode.c @@ -222,13 +222,17 @@ const unsigned char * sysfs_get_name(struct sysfs_dirent *sd) static inline void orphan_all_buffers(struct inode *node) { - struct sysfs_buffer_collection *set = node->i_private; + struct sysfs_buffer_collection *set; struct sysfs_buffer *buf; mutex_lock_nested(&node->i_mutex, I_MUTEX_CHILD); - if (node->i_private) { - list_for_each_entry(buf, &set->associates, associates) + set = node->i_private; + if (set) { + list_for_each_entry(buf, &set->associates, associates) { + down(&buf->sem); buf->orphaned = 1; + up(&buf->sem); + } } mutex_unlock(&node->i_mutex); } |