[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>
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Linus Torvalds

parent
d9a9cdfb07
commit
e7b0d26a86
@@ -168,12 +168,12 @@ sysfs_read_file(struct file *file, char __user *buf, size_t count, loff_t *ppos)
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ssize_t retval = 0;
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down(&buffer->sem);
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if (buffer->orphaned) {
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retval = -ENODEV;
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goto out;
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}
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if (buffer->needs_read_fill) {
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if ((retval = fill_read_buffer(file->f_path.dentry,buffer)))
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if (buffer->orphaned)
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retval = -ENODEV;
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else
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retval = fill_read_buffer(file->f_path.dentry,buffer);
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if (retval)
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goto out;
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}
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pr_debug("%s: count = %zd, ppos = %lld, buf = %s\n",
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