diff options
Diffstat (limited to 'fs/sysfs')
| -rw-r--r-- | fs/sysfs/Kconfig | 23 | ||||
| -rw-r--r-- | fs/sysfs/bin.c | 259 | ||||
| -rw-r--r-- | fs/sysfs/dir.c | 33 | ||||
| -rw-r--r-- | fs/sysfs/file.c | 26 | ||||
| -rw-r--r-- | fs/sysfs/inode.c | 17 | ||||
| -rw-r--r-- | fs/sysfs/mount.c | 6 | ||||
| -rw-r--r-- | fs/sysfs/sysfs.h | 3 |
7 files changed, 347 insertions, 20 deletions
diff --git a/fs/sysfs/Kconfig b/fs/sysfs/Kconfig new file mode 100644 index 00000000000..f4b67588b9d --- /dev/null +++ b/fs/sysfs/Kconfig @@ -0,0 +1,23 @@ +config SYSFS + bool "sysfs file system support" if EMBEDDED + default y + help + The sysfs filesystem is a virtual filesystem that the kernel uses to + export internal kernel objects, their attributes, and their + relationships to one another. + + Users can use sysfs to ascertain useful information about the running + kernel, such as the devices the kernel has discovered on each bus and + which driver each is bound to. sysfs can also be used to tune devices + and other kernel subsystems. + + Some system agents rely on the information in sysfs to operate. + /sbin/hotplug uses device and object attributes in sysfs to assist in + delegating policy decisions, like persistently naming devices. + + sysfs is currently used by the block subsystem to mount the root + partition. If sysfs is disabled you must specify the boot device on + the kernel boot command line via its major and minor numbers. For + example, "root=03:01" for /dev/hda1. + + Designers of embedded systems may wish to say N here to conserve space. diff --git a/fs/sysfs/bin.c b/fs/sysfs/bin.c index 66f6e58a7e4..07703d3ff4a 100644 --- a/fs/sysfs/bin.c +++ b/fs/sysfs/bin.c @@ -21,15 +21,28 @@ #include <linux/module.h> #include <linux/slab.h> #include <linux/mutex.h> +#include <linux/mm.h> #include <asm/uaccess.h> #include "sysfs.h" +/* + * There's one bin_buffer for each open file. + * + * filp->private_data points to bin_buffer and + * sysfs_dirent->s_bin_attr.buffers points to a the bin_buffer s + * sysfs_dirent->s_bin_attr.buffers is protected by sysfs_bin_lock + */ +static DEFINE_MUTEX(sysfs_bin_lock); + struct bin_buffer { - struct mutex mutex; - void *buffer; - int mmapped; + struct mutex mutex; + void *buffer; + int mmapped; + struct vm_operations_struct *vm_ops; + struct file *file; + struct hlist_node list; }; static int @@ -63,6 +76,9 @@ read(struct file *file, char __user *userbuf, size_t bytes, loff_t *off) int count = min_t(size_t, bytes, PAGE_SIZE); char *temp; + if (!bytes) + return 0; + if (size) { if (offs > size) return 0; @@ -131,6 +147,9 @@ static ssize_t write(struct file *file, const char __user *userbuf, int count = min_t(size_t, bytes, PAGE_SIZE); char *temp; + if (!bytes) + return 0; + if (size) { if (offs > size) return 0; @@ -162,6 +181,175 @@ out_free: return count; } +static void bin_vma_open(struct vm_area_struct *vma) +{ + struct file *file = vma->vm_file; + struct bin_buffer *bb = file->private_data; + struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata; + + if (!bb->vm_ops || !bb->vm_ops->open) + return; + + if (!sysfs_get_active_two(attr_sd)) + return; + + bb->vm_ops->open(vma); + + sysfs_put_active_two(attr_sd); +} + +static void bin_vma_close(struct vm_area_struct *vma) +{ + struct file *file = vma->vm_file; + struct bin_buffer *bb = file->private_data; + struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata; + + if (!bb->vm_ops || !bb->vm_ops->close) + return; + + if (!sysfs_get_active_two(attr_sd)) + return; + + bb->vm_ops->close(vma); + + sysfs_put_active_two(attr_sd); +} + +static int bin_fault(struct vm_area_struct *vma, struct vm_fault *vmf) +{ + struct file *file = vma->vm_file; + struct bin_buffer *bb = file->private_data; + struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata; + int ret; + + if (!bb->vm_ops || !bb->vm_ops->fault) + return VM_FAULT_SIGBUS; + + if (!sysfs_get_active_two(attr_sd)) + return VM_FAULT_SIGBUS; + + ret = bb->vm_ops->fault(vma, vmf); + + sysfs_put_active_two(attr_sd); + return ret; +} + +static int bin_page_mkwrite(struct vm_area_struct *vma, struct page *page) +{ + struct file *file = vma->vm_file; + struct bin_buffer *bb = file->private_data; + struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata; + int ret; + + if (!bb->vm_ops) + return -EINVAL; + + if (!bb->vm_ops->page_mkwrite) + return 0; + + if (!sysfs_get_active_two(attr_sd)) + return -EINVAL; + + ret = bb->vm_ops->page_mkwrite(vma, page); + + sysfs_put_active_two(attr_sd); + return ret; +} + +static int bin_access(struct vm_area_struct *vma, unsigned long addr, + void *buf, int len, int write) +{ + struct file *file = vma->vm_file; + struct bin_buffer *bb = file->private_data; + struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata; + int ret; + + if (!bb->vm_ops || !bb->vm_ops->access) + return -EINVAL; + + if (!sysfs_get_active_two(attr_sd)) + return -EINVAL; + + ret = bb->vm_ops->access(vma, addr, buf, len, write); + + sysfs_put_active_two(attr_sd); + return ret; +} + +#ifdef CONFIG_NUMA +static int bin_set_policy(struct vm_area_struct *vma, struct mempolicy *new) +{ + struct file *file = vma->vm_file; + struct bin_buffer *bb = file->private_data; + struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata; + int ret; + + if (!bb->vm_ops || !bb->vm_ops->set_policy) + return 0; + + if (!sysfs_get_active_two(attr_sd)) + return -EINVAL; + + ret = bb->vm_ops->set_policy(vma, new); + + sysfs_put_active_two(attr_sd); + return ret; +} + +static struct mempolicy *bin_get_policy(struct vm_area_struct *vma, + unsigned long addr) +{ + struct file *file = vma->vm_file; + struct bin_buffer *bb = file->private_data; + struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata; + struct mempolicy *pol; + + if (!bb->vm_ops || !bb->vm_ops->get_policy) + return vma->vm_policy; + + if (!sysfs_get_active_two(attr_sd)) + return vma->vm_policy; + + pol = bb->vm_ops->get_policy(vma, addr); + + sysfs_put_active_two(attr_sd); + return pol; +} + +static int bin_migrate(struct vm_area_struct *vma, const nodemask_t *from, + const nodemask_t *to, unsigned long flags) +{ + struct file *file = vma->vm_file; + struct bin_buffer *bb = file->private_data; + struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata; + int ret; + + if (!bb->vm_ops || !bb->vm_ops->migrate) + return 0; + + if (!sysfs_get_active_two(attr_sd)) + return 0; + + ret = bb->vm_ops->migrate(vma, from, to, flags); + + sysfs_put_active_two(attr_sd); + return ret; +} +#endif + +static struct vm_operations_struct bin_vm_ops = { + .open = bin_vma_open, + .close = bin_vma_close, + .fault = bin_fault, + .page_mkwrite = bin_page_mkwrite, + .access = bin_access, +#ifdef CONFIG_NUMA + .set_policy = bin_set_policy, + .get_policy = bin_get_policy, + .migrate = bin_migrate, +#endif +}; + static int mmap(struct file *file, struct vm_area_struct *vma) { struct bin_buffer *bb = file->private_data; @@ -173,18 +361,37 @@ static int mmap(struct file *file, struct vm_area_struct *vma) mutex_lock(&bb->mutex); /* need attr_sd for attr, its parent for kobj */ + rc = -ENODEV; if (!sysfs_get_active_two(attr_sd)) - return -ENODEV; + goto out_unlock; rc = -EINVAL; - if (attr->mmap) - rc = attr->mmap(kobj, attr, vma); + if (!attr->mmap) + goto out_put; + + rc = attr->mmap(kobj, attr, vma); + if (rc) + goto out_put; - if (rc == 0 && !bb->mmapped) - bb->mmapped = 1; - else - sysfs_put_active_two(attr_sd); + /* + * PowerPC's pci_mmap of legacy_mem uses shmem_zero_setup() + * to satisfy versions of X which crash if the mmap fails: that + * substitutes a new vm_file, and we don't then want bin_vm_ops. + */ + if (vma->vm_file != file) + goto out_put; + rc = -EINVAL; + if (bb->mmapped && bb->vm_ops != vma->vm_ops) + goto out_put; + + rc = 0; + bb->mmapped = 1; + bb->vm_ops = vma->vm_ops; + vma->vm_ops = &bin_vm_ops; +out_put: + sysfs_put_active_two(attr_sd); +out_unlock: mutex_unlock(&bb->mutex); return rc; @@ -217,8 +424,13 @@ static int open(struct inode * inode, struct file * file) goto err_out; mutex_init(&bb->mutex); + bb->file = file; file->private_data = bb; + mutex_lock(&sysfs_bin_lock); + hlist_add_head(&bb->list, &attr_sd->s_bin_attr.buffers); + mutex_unlock(&sysfs_bin_lock); + /* open succeeded, put active references */ sysfs_put_active_two(attr_sd); return 0; @@ -231,11 +443,12 @@ static int open(struct inode * inode, struct file * file) static int release(struct inode * inode, struct file * file) { - struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata; struct bin_buffer *bb = file->private_data; - if (bb->mmapped) - sysfs_put_active_two(attr_sd); + mutex_lock(&sysfs_bin_lock); + hlist_del(&bb->list); + mutex_unlock(&sysfs_bin_lock); + kfree(bb->buffer); kfree(bb); return 0; @@ -250,6 +463,26 @@ const struct file_operations bin_fops = { .release = release, }; + +void unmap_bin_file(struct sysfs_dirent *attr_sd) +{ + struct bin_buffer *bb; + struct hlist_node *tmp; + + if (sysfs_type(attr_sd) != SYSFS_KOBJ_BIN_ATTR) + return; + + mutex_lock(&sysfs_bin_lock); + + hlist_for_each_entry(bb, tmp, &attr_sd->s_bin_attr.buffers, list) { + struct inode *inode = bb->file->f_path.dentry->d_inode; + + unmap_mapping_range(inode->i_mapping, 0, 0, 1); + } + + mutex_unlock(&sysfs_bin_lock); +} + /** * sysfs_create_bin_file - create binary file for object. * @kobj: object. diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c index 82d3b79d0e0..66aeb4fff0c 100644 --- a/fs/sysfs/dir.c +++ b/fs/sysfs/dir.c @@ -434,6 +434,26 @@ int __sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd) } /** + * sysfs_pathname - return full path to sysfs dirent + * @sd: sysfs_dirent whose path we want + * @path: caller allocated buffer + * + * Gives the name "/" to the sysfs_root entry; any path returned + * is relative to wherever sysfs is mounted. + * + * XXX: does no error checking on @path size + */ +static char *sysfs_pathname(struct sysfs_dirent *sd, char *path) +{ + if (sd->s_parent) { + sysfs_pathname(sd->s_parent, path); + strcat(path, "/"); + } + strcat(path, sd->s_name); + return path; +} + +/** * sysfs_add_one - add sysfs_dirent to parent * @acxt: addrm context to use * @sd: sysfs_dirent to be added @@ -458,8 +478,16 @@ int sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd) int ret; ret = __sysfs_add_one(acxt, sd); - WARN(ret == -EEXIST, KERN_WARNING "sysfs: duplicate filename '%s' " - "can not be created\n", sd->s_name); + if (ret == -EEXIST) { + char *path = kzalloc(PATH_MAX, GFP_KERNEL); + WARN(1, KERN_WARNING + "sysfs: cannot create duplicate filename '%s'\n", + (path == NULL) ? sd->s_name : + strcat(strcat(sysfs_pathname(acxt->parent_sd, path), "/"), + sd->s_name)); + kfree(path); + } + return ret; } @@ -581,6 +609,7 @@ void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt) sysfs_drop_dentry(sd); sysfs_deactivate(sd); + unmap_bin_file(sd); sysfs_put(sd); } } diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c index 1f4a3f87726..289c43a4726 100644 --- a/fs/sysfs/file.c +++ b/fs/sysfs/file.c @@ -659,13 +659,16 @@ void sysfs_remove_file_from_group(struct kobject *kobj, EXPORT_SYMBOL_GPL(sysfs_remove_file_from_group); struct sysfs_schedule_callback_struct { - struct kobject *kobj; + struct list_head workq_list; + struct kobject *kobj; void (*func)(void *); void *data; struct module *owner; struct work_struct work; }; +static DEFINE_MUTEX(sysfs_workq_mutex); +static LIST_HEAD(sysfs_workq); static void sysfs_schedule_callback_work(struct work_struct *work) { struct sysfs_schedule_callback_struct *ss = container_of(work, @@ -674,6 +677,9 @@ static void sysfs_schedule_callback_work(struct work_struct *work) (ss->func)(ss->data); kobject_put(ss->kobj); module_put(ss->owner); + mutex_lock(&sysfs_workq_mutex); + list_del(&ss->workq_list); + mutex_unlock(&sysfs_workq_mutex); kfree(ss); } @@ -695,15 +701,25 @@ static void sysfs_schedule_callback_work(struct work_struct *work) * until @func returns. * * Returns 0 if the request was submitted, -ENOMEM if storage could not - * be allocated, -ENODEV if a reference to @owner isn't available. + * be allocated, -ENODEV if a reference to @owner isn't available, + * -EAGAIN if a callback has already been scheduled for @kobj. */ int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *), void *data, struct module *owner) { - struct sysfs_schedule_callback_struct *ss; + struct sysfs_schedule_callback_struct *ss, *tmp; if (!try_module_get(owner)) return -ENODEV; + + mutex_lock(&sysfs_workq_mutex); + list_for_each_entry_safe(ss, tmp, &sysfs_workq, workq_list) + if (ss->kobj == kobj) { + mutex_unlock(&sysfs_workq_mutex); + return -EAGAIN; + } + mutex_unlock(&sysfs_workq_mutex); + ss = kmalloc(sizeof(*ss), GFP_KERNEL); if (!ss) { module_put(owner); @@ -715,6 +731,10 @@ int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *), ss->data = data; ss->owner = owner; INIT_WORK(&ss->work, sysfs_schedule_callback_work); + INIT_LIST_HEAD(&ss->workq_list); + mutex_lock(&sysfs_workq_mutex); + list_add_tail(&ss->workq_list, &sysfs_workq); + mutex_unlock(&sysfs_workq_mutex); schedule_work(&ss->work); return 0; } diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c index dfa3d94cfc7..555f0ff988d 100644 --- a/fs/sysfs/inode.c +++ b/fs/sysfs/inode.c @@ -147,6 +147,7 @@ static void sysfs_init_inode(struct sysfs_dirent *sd, struct inode *inode) { struct bin_attribute *bin_attr; + inode->i_private = sysfs_get(sd); inode->i_mapping->a_ops = &sysfs_aops; inode->i_mapping->backing_dev_info = &sysfs_backing_dev_info; inode->i_op = &sysfs_inode_operations; @@ -214,6 +215,22 @@ struct inode * sysfs_get_inode(struct sysfs_dirent *sd) return inode; } +/* + * The sysfs_dirent serves as both an inode and a directory entry for sysfs. + * To prevent the sysfs inode numbers from being freed prematurely we take a + * reference to sysfs_dirent from the sysfs inode. A + * super_operations.delete_inode() implementation is needed to drop that + * reference upon inode destruction. + */ +void sysfs_delete_inode(struct inode *inode) +{ + struct sysfs_dirent *sd = inode->i_private; + + truncate_inode_pages(&inode->i_data, 0); + clear_inode(inode); + sysfs_put(sd); +} + int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const char *name) { struct sysfs_addrm_cxt acxt; diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c index ab343e371d6..49749955cca 100644 --- a/fs/sysfs/mount.c +++ b/fs/sysfs/mount.c @@ -17,11 +17,10 @@ #include <linux/pagemap.h> #include <linux/init.h> #include <linux/module.h> +#include <linux/magic.h> #include "sysfs.h" -/* Random magic number */ -#define SYSFS_MAGIC 0x62656572 static struct vfsmount *sysfs_mount; struct super_block * sysfs_sb = NULL; @@ -30,6 +29,7 @@ struct kmem_cache *sysfs_dir_cachep; static const struct super_operations sysfs_ops = { .statfs = simple_statfs, .drop_inode = generic_delete_inode, + .delete_inode = sysfs_delete_inode, }; struct sysfs_dirent sysfs_root = { @@ -53,7 +53,9 @@ static int sysfs_fill_super(struct super_block *sb, void *data, int silent) sysfs_sb = sb; /* get root inode, initialize and unlock it */ + mutex_lock(&sysfs_mutex); inode = sysfs_get_inode(&sysfs_root); + mutex_unlock(&sysfs_mutex); if (!inode) { pr_debug("sysfs: could not get root inode\n"); return -ENOMEM; diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h index 93c6d6b27c4..3fa0d98481e 100644 --- a/fs/sysfs/sysfs.h +++ b/fs/sysfs/sysfs.h @@ -28,6 +28,7 @@ struct sysfs_elem_attr { struct sysfs_elem_bin_attr { struct bin_attribute *bin_attr; + struct hlist_head buffers; }; /* @@ -145,6 +146,7 @@ static inline void __sysfs_put(struct sysfs_dirent *sd) * inode.c */ struct inode *sysfs_get_inode(struct sysfs_dirent *sd); +void sysfs_delete_inode(struct inode *inode); int sysfs_setattr(struct dentry *dentry, struct iattr *iattr); int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const char *name); int sysfs_inode_init(void); @@ -163,6 +165,7 @@ int sysfs_add_file_mode(struct sysfs_dirent *dir_sd, * bin.c */ extern const struct file_operations bin_fops; +void unmap_bin_file(struct sysfs_dirent *attr_sd); /* * symlink.c |