diff options
| -rw-r--r-- | drivers/android/binderfs.c | 104 |
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)) |