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-rw-r--r--drivers/android/binderfs.c104
1 files changed, 98 insertions, 6 deletions
diff --git a/drivers/android/binderfs.c b/drivers/android/binderfs.c
index 4990d65d4850..89788969bc04 100644
--- a/drivers/android/binderfs.c
+++ b/drivers/android/binderfs.c
@@ -20,6 +20,7 @@
#include <linux/parser.h>
#include <linux/radix-tree.h>
#include <linux/sched.h>
+#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/spinlock_types.h>
#include <linux/stddef.h>
@@ -45,6 +46,24 @@ static DEFINE_MUTEX(binderfs_minors_mutex);
static DEFINE_IDA(binderfs_minors);
/**
+ * binderfs_mount_opts - mount options for binderfs
+ * @max: maximum number of allocatable binderfs binder devices
+ */
+struct binderfs_mount_opts {
+ int max;
+};
+
+enum {
+ Opt_max,
+ Opt_err
+};
+
+static const match_table_t tokens = {
+ { Opt_max, "max=%d" },
+ { Opt_err, NULL }
+};
+
+/**
* binderfs_info - information about a binderfs mount
* @ipc_ns: The ipc namespace the binderfs mount belongs to.
* @control_dentry: This records the dentry of this binderfs mount
@@ -53,13 +72,16 @@ static DEFINE_IDA(binderfs_minors);
* created.
* @root_gid: gid that needs to be used when a new binder device is
* created.
+ * @mount_opts: The mount options in use.
+ * @device_count: The current number of allocated binder devices.
*/
struct binderfs_info {
struct ipc_namespace *ipc_ns;
struct dentry *control_dentry;
kuid_t root_uid;
kgid_t root_gid;
-
+ struct binderfs_mount_opts mount_opts;
+ int device_count;
};
static inline struct binderfs_info *BINDERFS_I(const struct inode *inode)
@@ -108,10 +130,17 @@ static int binderfs_binder_device_create(struct inode *ref_inode,
/* Reserve new minor number for the new device. */
mutex_lock(&binderfs_minors_mutex);
- minor = ida_alloc_max(&binderfs_minors, BINDERFS_MAX_MINOR, GFP_KERNEL);
- mutex_unlock(&binderfs_minors_mutex);
- if (minor < 0)
+ if (++info->device_count <= info->mount_opts.max)
+ minor = ida_alloc_max(&binderfs_minors, BINDERFS_MAX_MINOR,
+ GFP_KERNEL);
+ else
+ minor = -ENOSPC;
+ if (minor < 0) {
+ --info->device_count;
+ mutex_unlock(&binderfs_minors_mutex);
return minor;
+ }
+ mutex_unlock(&binderfs_minors_mutex);
ret = -ENOMEM;
device = kzalloc(sizeof(*device), GFP_KERNEL);
@@ -185,6 +214,7 @@ err:
kfree(name);
kfree(device);
mutex_lock(&binderfs_minors_mutex);
+ --info->device_count;
ida_free(&binderfs_minors, minor);
mutex_unlock(&binderfs_minors_mutex);
iput(inode);
@@ -230,6 +260,7 @@ static long binder_ctl_ioctl(struct file *file, unsigned int cmd,
static void binderfs_evict_inode(struct inode *inode)
{
struct binder_device *device = inode->i_private;
+ struct binderfs_info *info = BINDERFS_I(inode);
clear_inode(inode);
@@ -237,6 +268,7 @@ static void binderfs_evict_inode(struct inode *inode)
return;
mutex_lock(&binderfs_minors_mutex);
+ --info->device_count;
ida_free(&binderfs_minors, device->miscdev.minor);
mutex_unlock(&binderfs_minors_mutex);
@@ -244,9 +276,65 @@ static void binderfs_evict_inode(struct inode *inode)
kfree(device);
}
+/**
+ * binderfs_parse_mount_opts - parse binderfs mount options
+ * @data: options to set (can be NULL in which case defaults are used)
+ */
+static int binderfs_parse_mount_opts(char *data,
+ struct binderfs_mount_opts *opts)
+{
+ char *p;
+ opts->max = BINDERFS_MAX_MINOR;
+
+ while ((p = strsep(&data, ",")) != NULL) {
+ substring_t args[MAX_OPT_ARGS];
+ int token;
+ int max_devices;
+
+ if (!*p)
+ continue;
+
+ token = match_token(p, tokens, args);
+ switch (token) {
+ case Opt_max:
+ if (match_int(&args[0], &max_devices) ||
+ (max_devices < 0 ||
+ (max_devices > BINDERFS_MAX_MINOR)))
+ return -EINVAL;
+
+ opts->max = max_devices;
+ break;
+ default:
+ pr_err("Invalid mount options\n");
+ return -EINVAL;
+ }
+ }
+
+ return 0;
+}
+
+static int binderfs_remount(struct super_block *sb, int *flags, char *data)
+{
+ struct binderfs_info *info = sb->s_fs_info;
+ return binderfs_parse_mount_opts(data, &info->mount_opts);
+}
+
+static int binderfs_show_mount_opts(struct seq_file *seq, struct dentry *root)
+{
+ struct binderfs_info *info;
+
+ info = root->d_sb->s_fs_info;
+ if (info->mount_opts.max <= BINDERFS_MAX_MINOR)
+ seq_printf(seq, ",max=%d", info->mount_opts.max);
+
+ return 0;
+}
+
static const struct super_operations binderfs_super_ops = {
- .statfs = simple_statfs,
- .evict_inode = binderfs_evict_inode,
+ .evict_inode = binderfs_evict_inode,
+ .remount_fs = binderfs_remount,
+ .show_options = binderfs_show_mount_opts,
+ .statfs = simple_statfs,
};
static int binderfs_rename(struct inode *old_dir, struct dentry *old_dentry,
@@ -407,6 +495,10 @@ static int binderfs_fill_super(struct super_block *sb, void *data, int silent)
if (!info)
goto err_without_dentry;
+ ret = binderfs_parse_mount_opts(data, &info->mount_opts);
+ if (ret)
+ goto err_without_dentry;
+
info->ipc_ns = ipc_ns;
info->root_gid = make_kgid(sb->s_user_ns, 0);
if (!gid_valid(info->root_gid))