Messages in this thread Patch in this message | | | From | Nicolai Stange <> | Subject | [PATCH v4 7/8] debugfs: unproxify files created through debugfs_create_blob() | Date | Tue, 23 Feb 2016 15:00:48 +0100 |
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Currently, the struct file_operations fops_blob associated with files created through the debugfs_create_blob() helpers are not file lifetime aware.
Thus, a lifetime managing proxy is created around fops_blob each time such a file is opened which is an unnecessary waste of resources.
Implement file lifetime management for the fops_bool file_operations. Namely, make read_file_blob() safe gainst file removals by means of debugfs_use_file_start() and debugfs_use_file_finish().
Make debugfs_create_blob() create its files in non-proxying operation mode by means of debugfs_create_file_unsafe().
Signed-off-by: Nicolai Stange <nicstange@gmail.com> --- fs/debugfs/file.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c index da24e0b..036ec3f 100644 --- a/fs/debugfs/file.c +++ b/fs/debugfs/file.c @@ -843,8 +843,15 @@ static ssize_t read_file_blob(struct file *file, char __user *user_buf, size_t count, loff_t *ppos) { struct debugfs_blob_wrapper *blob = file->private_data; - return simple_read_from_buffer(user_buf, count, ppos, blob->data, - blob->size); + ssize_t r; + int srcu_idx; + + r = debugfs_use_file_start(F_DENTRY(file), &srcu_idx); + if (likely(!r)) + r = simple_read_from_buffer(user_buf, count, ppos, blob->data, + blob->size); + debugfs_use_file_finish(srcu_idx); + return r; } static const struct file_operations fops_blob = { @@ -881,7 +888,7 @@ struct dentry *debugfs_create_blob(const char *name, umode_t mode, struct dentry *parent, struct debugfs_blob_wrapper *blob) { - return debugfs_create_file(name, mode, parent, blob, &fops_blob); + return debugfs_create_file_unsafe(name, mode, parent, blob, &fops_blob); } EXPORT_SYMBOL_GPL(debugfs_create_blob); -- 2.7.1
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