[PATCH v2 2/4] binder: Add stats, state and transactions files

From: Hridya Valsaraju
Date: Thu Aug 29 2019 - 17:18:44 EST


The following binder stat files currently live in debugfs.

/sys/kernel/debug/binder/state
/sys/kernel/debug/binder/stats
/sys/kernel/debug/binder/transactions

This patch makes these files available in a binderfs instance
mounted with the mount option 'stats=global'. For example, if a binderfs
instance is mounted at path /dev/binderfs, the above files will be
available at the following locations:

/dev/binderfs/binder_logs/state
/dev/binderfs/binder_logs/stats
/dev/binderfs/binder_logs/transactions

This provides a way to access them even when debugfs is not mounted.

Signed-off-by: Hridya Valsaraju <hridya@xxxxxxxxxx>
---

Changes in v2:
- Consistently name variables across functions as per Christian
Brauner.
- Improve check for binderfs device in binderfs_evict_inode()
as per Christian Brauner.

drivers/android/binder.c | 15 ++--
drivers/android/binder_internal.h | 8 ++
drivers/android/binderfs.c | 140 +++++++++++++++++++++++++++++-
3 files changed, 153 insertions(+), 10 deletions(-)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index ca6b21a53321..de795bd229c4 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -6055,7 +6055,7 @@ static void print_binder_proc_stats(struct seq_file *m,
}


-static int state_show(struct seq_file *m, void *unused)
+int binder_state_show(struct seq_file *m, void *unused)
{
struct binder_proc *proc;
struct binder_node *node;
@@ -6094,7 +6094,7 @@ static int state_show(struct seq_file *m, void *unused)
return 0;
}

-static int stats_show(struct seq_file *m, void *unused)
+int binder_stats_show(struct seq_file *m, void *unused)
{
struct binder_proc *proc;

@@ -6110,7 +6110,7 @@ static int stats_show(struct seq_file *m, void *unused)
return 0;
}

-static int transactions_show(struct seq_file *m, void *unused)
+int binder_transactions_show(struct seq_file *m, void *unused)
{
struct binder_proc *proc;

@@ -6198,9 +6198,6 @@ const struct file_operations binder_fops = {
.release = binder_release,
};

-DEFINE_SHOW_ATTRIBUTE(state);
-DEFINE_SHOW_ATTRIBUTE(stats);
-DEFINE_SHOW_ATTRIBUTE(transactions);
DEFINE_SHOW_ATTRIBUTE(transaction_log);

static int __init init_binder_device(const char *name)
@@ -6256,17 +6253,17 @@ static int __init binder_init(void)
0444,
binder_debugfs_dir_entry_root,
NULL,
- &state_fops);
+ &binder_state_fops);
debugfs_create_file("stats",
0444,
binder_debugfs_dir_entry_root,
NULL,
- &stats_fops);
+ &binder_stats_fops);
debugfs_create_file("transactions",
0444,
binder_debugfs_dir_entry_root,
NULL,
- &transactions_fops);
+ &binder_transactions_fops);
debugfs_create_file("transaction_log",
0444,
binder_debugfs_dir_entry_root,
diff --git a/drivers/android/binder_internal.h b/drivers/android/binder_internal.h
index fe8c745dc8e0..12ef96f256c6 100644
--- a/drivers/android/binder_internal.h
+++ b/drivers/android/binder_internal.h
@@ -57,4 +57,12 @@ static inline int __init init_binderfs(void)
}
#endif

+int binder_stats_show(struct seq_file *m, void *unused);
+DEFINE_SHOW_ATTRIBUTE(binder_stats);
+
+int binder_state_show(struct seq_file *m, void *unused);
+DEFINE_SHOW_ATTRIBUTE(binder_state);
+
+int binder_transactions_show(struct seq_file *m, void *unused);
+DEFINE_SHOW_ATTRIBUTE(binder_transactions);
#endif /* _LINUX_BINDER_INTERNAL_H */
diff --git a/drivers/android/binderfs.c b/drivers/android/binderfs.c
index 7045bfe5b52b..0e1e7c87cd33 100644
--- a/drivers/android/binderfs.c
+++ b/drivers/android/binderfs.c
@@ -280,7 +280,7 @@ static void binderfs_evict_inode(struct inode *inode)

clear_inode(inode);

- if (!device)
+ if (!S_ISCHR(inode->i_mode) || !device)
return;

mutex_lock(&binderfs_minors_mutex);
@@ -502,6 +502,141 @@ static const struct inode_operations binderfs_dir_inode_operations = {
.unlink = binderfs_unlink,
};

+static struct inode *binderfs_make_inode(struct super_block *sb, int mode)
+{
+ struct inode *ret;
+
+ ret = new_inode(sb);
+ if (ret) {
+ ret->i_ino = iunique(sb, BINDERFS_MAX_MINOR + INODE_OFFSET);
+ ret->i_mode = mode;
+ ret->i_atime = ret->i_mtime = ret->i_ctime = current_time(ret);
+ }
+ return ret;
+}
+
+static struct dentry *binderfs_create_dentry(struct dentry *parent,
+ const char *name)
+{
+ struct dentry *dentry;
+
+ dentry = lookup_one_len(name, parent, strlen(name));
+ if (IS_ERR(dentry))
+ return dentry;
+
+ /* Return error if the file/dir already exists. */
+ if (d_really_is_positive(dentry)) {
+ dput(dentry);
+ return ERR_PTR(-EEXIST);
+ }
+
+ return dentry;
+}
+
+static struct dentry *binderfs_create_file(struct dentry *parent,
+ const char *name,
+ const struct file_operations *fops,
+ void *data)
+{
+ struct dentry *dentry;
+ struct inode *new_inode, *parent_inode;
+ struct super_block *sb;
+
+ parent_inode = parent->d_inode;
+ inode_lock(parent_inode);
+
+ dentry = binderfs_create_dentry(parent, name);
+ if (IS_ERR(dentry))
+ goto out;
+
+ sb = parent_inode->i_sb;
+ new_inode = binderfs_make_inode(sb, S_IFREG | 0444);
+ if (!new_inode) {
+ dput(dentry);
+ dentry = ERR_PTR(-ENOMEM);
+ goto out;
+ }
+
+ new_inode->i_fop = fops;
+ new_inode->i_private = data;
+ d_instantiate(dentry, new_inode);
+ fsnotify_create(parent_inode, dentry);
+
+out:
+ inode_unlock(parent_inode);
+ return dentry;
+}
+
+static struct dentry *binderfs_create_dir(struct dentry *parent,
+ const char *name)
+{
+ struct dentry *dentry;
+ struct inode *new_inode, *parent_inode;
+ struct super_block *sb;
+
+ parent_inode = d_inode(parent);
+ inode_lock(parent_inode);
+
+ dentry = binderfs_create_dentry(parent, name);
+ if (IS_ERR(dentry))
+ goto out;
+
+ sb = parent_inode->i_sb;
+ new_inode = binderfs_make_inode(sb, S_IFDIR | 0755);
+ if (!new_inode) {
+ dput(dentry);
+ dentry = ERR_PTR(-ENOMEM);
+ goto out;
+ }
+
+ new_inode->i_fop = &simple_dir_operations;
+ new_inode->i_op = &simple_dir_inode_operations;
+
+ inc_nlink(new_inode);
+ d_instantiate(dentry, new_inode);
+ inc_nlink(parent_inode);
+ fsnotify_mkdir(parent_inode, dentry);
+
+out:
+ inode_unlock(parent_inode);
+ return dentry;
+}
+
+static int init_binder_logs(struct super_block *sb)
+{
+ struct dentry *binder_logs_root_dir, *dentry;
+ int ret = 0;
+
+ binder_logs_root_dir = binderfs_create_dir(sb->s_root,
+ "binder_logs");
+ if (IS_ERR(binder_logs_root_dir)) {
+ ret = PTR_ERR(binder_logs_root_dir);
+ goto out;
+ }
+
+ dentry = binderfs_create_file(binder_logs_root_dir, "stats",
+ &binder_stats_fops, NULL);
+ if (IS_ERR(dentry)) {
+ ret = PTR_ERR(dentry);
+ goto out;
+ }
+
+ dentry = binderfs_create_file(binder_logs_root_dir, "state",
+ &binder_state_fops, NULL);
+ if (IS_ERR(dentry)) {
+ ret = PTR_ERR(dentry);
+ goto out;
+ }
+
+ dentry = binderfs_create_file(binder_logs_root_dir, "transactions",
+ &binder_transactions_fops, NULL);
+ if (IS_ERR(dentry))
+ ret = PTR_ERR(dentry);
+
+out:
+ return ret;
+}
+
static int binderfs_fill_super(struct super_block *sb, void *data, int silent)
{
int ret;
@@ -580,6 +715,9 @@ static int binderfs_fill_super(struct super_block *sb, void *data, int silent)

}

+ if (info->mount_opts.stats_mode == STATS_GLOBAL)
+ return init_binder_logs(sb);
+
return 0;
}

--
2.23.0.187.g17f5b7556c-goog