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authorNicolai Stange <nicstange@gmail.com>2016-03-22 16:11:19 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2016-04-13 00:14:21 +0300
commit83b711cbf4ff42a9996c5f092762b3967d307d73 (patch)
tree9907e784c0f08708c52651cedd65bc355106bf06
parent4d45f7974ccf0aa783034fef2661573b3a28609e (diff)
downloadlinux-83b711cbf4ff42a9996c5f092762b3967d307d73.tar.xz
debugfs: unproxify files created through debugfs_create_blob()
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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--fs/debugfs/file.c13
1 files changed, 10 insertions, 3 deletions
diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c
index 8a548bee1b3d..2e86d66f7850 100644
--- a/fs/debugfs/file.c
+++ b/fs/debugfs/file.c
@@ -842,8 +842,15 @@ 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 = {
@@ -880,7 +887,7 @@ 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);