diff options
| -rw-r--r-- | fs/sysfs/file.c | 146 | ||||
| -rw-r--r-- | fs/sysfs/sysfs.h | 3 | ||||
| -rw-r--r-- | include/linux/kernfs.h | 26 |
3 files changed, 141 insertions, 34 deletions
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c index acba5835577e..cbebc335af8c 100644 --- a/fs/sysfs/file.c +++ b/fs/sysfs/file.c @@ -58,6 +58,17 @@ static struct sysfs_open_file *sysfs_of(struct file *file) } /* + * Determine the kernfs_ops for the given sysfs_dirent. This function must + * be called while holding an active reference. + */ +static const struct kernfs_ops *kernfs_ops(struct sysfs_dirent *sd) +{ + if (!sysfs_ignore_lockdep(sd)) + lockdep_assert_held(sd); + return sd->s_attr.ops; +} + +/* * Determine ktype->sysfs_ops for the given sysfs_dirent. This function * must be called while holding an active reference. */ @@ -180,7 +191,7 @@ static int kernfs_seq_show(struct seq_file *sf, void *v) of->event = atomic_read(&of->sd->s_attr.open->event); - return sysfs_kf_seq_show(sf, v); + return of->sd->s_attr.ops->seq_show(sf, v); } static const struct seq_operations kernfs_seq_ops = { @@ -201,6 +212,7 @@ static ssize_t kernfs_file_direct_read(struct sysfs_open_file *of, loff_t *ppos) { ssize_t len = min_t(size_t, count, PAGE_SIZE); + const struct kernfs_ops *ops; char *buf; buf = kmalloc(len, GFP_KERNEL); @@ -218,7 +230,11 @@ static ssize_t kernfs_file_direct_read(struct sysfs_open_file *of, goto out_free; } - len = sysfs_kf_bin_read(of, buf, len, *ppos); + ops = kernfs_ops(of->sd); + if (ops->read) + len = ops->read(of, buf, len, *ppos); + else + len = -EINVAL; sysfs_put_active(of->sd); mutex_unlock(&of->mutex); @@ -250,10 +266,10 @@ static ssize_t kernfs_file_read(struct file *file, char __user *user_buf, { struct sysfs_open_file *of = sysfs_of(file); - if (sysfs_is_bin(of->sd)) - return kernfs_file_direct_read(of, user_buf, count, ppos); - else + if (of->sd->s_flags & SYSFS_FLAG_HAS_SEQ_SHOW) return seq_read(file, user_buf, count, ppos); + else + return kernfs_file_direct_read(of, user_buf, count, ppos); } /* kernfs write callback for regular sysfs files */ @@ -312,6 +328,7 @@ static ssize_t kernfs_file_write(struct file *file, const char __user *user_buf, { struct sysfs_open_file *of = sysfs_of(file); ssize_t len = min_t(size_t, count, PAGE_SIZE); + const struct kernfs_ops *ops; char *buf; buf = kmalloc(len + 1, GFP_KERNEL); @@ -335,10 +352,11 @@ static ssize_t kernfs_file_write(struct file *file, const char __user *user_buf, goto out_free; } - if (sysfs_is_bin(of->sd)) - len = sysfs_kf_bin_write(of, buf, len, *ppos); + ops = kernfs_ops(of->sd); + if (ops->write) + len = ops->write(of, buf, len, *ppos); else - len = sysfs_kf_write(of, buf, len, *ppos); + len = -EINVAL; sysfs_put_active(of->sd); mutex_unlock(&of->mutex); @@ -524,6 +542,7 @@ static const struct vm_operations_struct kernfs_vm_ops = { static int kernfs_file_mmap(struct file *file, struct vm_area_struct *vma) { struct sysfs_open_file *of = sysfs_of(file); + const struct kernfs_ops *ops; int rc; mutex_lock(&of->mutex); @@ -532,8 +551,9 @@ static int kernfs_file_mmap(struct file *file, struct vm_area_struct *vma) if (!sysfs_get_active(of->sd)) goto out_unlock; - if (sysfs_is_bin(of->sd)) - rc = sysfs_kf_bin_mmap(of, vma); + ops = kernfs_ops(of->sd); + if (ops->mmap) + rc = ops->mmap(of, vma); if (rc) goto out_put; @@ -660,34 +680,19 @@ static void sysfs_put_open_dirent(struct sysfs_dirent *sd, static int kernfs_file_open(struct inode *inode, struct file *file) { struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata; - struct kobject *kobj = attr_sd->s_parent->priv; + const struct kernfs_ops *ops; struct sysfs_open_file *of; bool has_read, has_write, has_mmap; int error = -EACCES; - /* need attr_sd for attr and ops, its parent for kobj */ if (!sysfs_get_active(attr_sd)) return -ENODEV; - if (sysfs_is_bin(attr_sd)) { - struct bin_attribute *battr = attr_sd->priv; + ops = kernfs_ops(attr_sd); - has_read = battr->read || battr->mmap; - has_write = battr->write || battr->mmap; - has_mmap = battr->mmap; - } else { - const struct sysfs_ops *ops = sysfs_file_ops(attr_sd); - - /* every kobject with an attribute needs a ktype assigned */ - if (WARN(!ops, KERN_ERR - "missing sysfs attribute operations for kobject: %s\n", - kobject_name(kobj))) - goto err_out; - - has_read = ops->show; - has_write = ops->store; - has_mmap = false; - } + has_read = ops->seq_show || ops->read || ops->mmap; + has_write = ops->write || ops->mmap; + has_mmap = ops->mmap; /* check perms and supported operations */ if ((file->f_mode & FMODE_WRITE) && @@ -729,10 +734,10 @@ static int kernfs_file_open(struct inode *inode, struct file *file) * seq_file or is not requested. This unifies private data access * and readable regular files are the vast majority anyway. */ - if (sysfs_is_bin(attr_sd)) - error = seq_open(file, NULL); - else + if (ops->seq_show) error = seq_open(file, &kernfs_seq_ops); + else + error = seq_open(file, NULL); if (error) goto err_free; @@ -777,7 +782,7 @@ void sysfs_unmap_bin_file(struct sysfs_dirent *sd) struct sysfs_open_dirent *od; struct sysfs_open_file *of; - if (!sysfs_is_bin(sd)) + if (!(sd->s_flags & SYSFS_FLAG_HAS_MMAP)) return; spin_lock_irq(&sysfs_open_dirent_lock); @@ -880,23 +885,96 @@ const struct file_operations kernfs_file_operations = { .poll = kernfs_file_poll, }; +static const struct kernfs_ops sysfs_file_kfops_empty = { +}; + +static const struct kernfs_ops sysfs_file_kfops_ro = { + .seq_show = sysfs_kf_seq_show, +}; + +static const struct kernfs_ops sysfs_file_kfops_wo = { + .write = sysfs_kf_write, +}; + +static const struct kernfs_ops sysfs_file_kfops_rw = { + .seq_show = sysfs_kf_seq_show, + .write = sysfs_kf_write, +}; + +static const struct kernfs_ops sysfs_bin_kfops_ro = { + .read = sysfs_kf_bin_read, +}; + +static const struct kernfs_ops sysfs_bin_kfops_wo = { + .write = sysfs_kf_bin_write, +}; + +static const struct kernfs_ops sysfs_bin_kfops_rw = { + .read = sysfs_kf_bin_read, + .write = sysfs_kf_bin_write, + .mmap = sysfs_kf_bin_mmap, +}; + int sysfs_add_file_mode_ns(struct sysfs_dirent *dir_sd, const struct attribute *attr, int type, umode_t amode, const void *ns) { umode_t mode = (amode & S_IALLUGO) | S_IFREG; + const struct kernfs_ops *ops; struct sysfs_addrm_cxt acxt; struct sysfs_dirent *sd; int rc; + if (type == SYSFS_KOBJ_ATTR) { + struct kobject *kobj = dir_sd->priv; + const struct sysfs_ops *sysfs_ops = kobj->ktype->sysfs_ops; + + /* every kobject with an attribute needs a ktype assigned */ + if (WARN(!sysfs_ops, KERN_ERR + "missing sysfs attribute operations for kobject: %s\n", + kobject_name(kobj))) + return -EINVAL; + + if (sysfs_ops->show && sysfs_ops->store) + ops = &sysfs_file_kfops_rw; + else if (sysfs_ops->show) + ops = &sysfs_file_kfops_ro; + else if (sysfs_ops->store) + ops = &sysfs_file_kfops_wo; + else + ops = &sysfs_file_kfops_empty; + } else { + struct bin_attribute *battr = (void *)attr; + + if ((battr->read && battr->write) || battr->mmap) + ops = &sysfs_bin_kfops_rw; + else if (battr->read) + ops = &sysfs_bin_kfops_ro; + else if (battr->write) + ops = &sysfs_bin_kfops_wo; + else + ops = &sysfs_file_kfops_empty; + } + sd = sysfs_new_dirent(attr->name, mode, type); if (!sd) return -ENOMEM; + sd->s_attr.ops = ops; sd->s_ns = ns; sd->priv = (void *)attr; sysfs_dirent_init_lockdep(sd); + /* + * sd->s_attr.ops is accesible only while holding active ref. We + * need to know whether some ops are implemented outside active + * ref. Cache their existence in flags. + */ + if (ops->seq_show) + sd->s_flags |= SYSFS_FLAG_HAS_SEQ_SHOW; + if (ops->mmap) + sd->s_flags |= SYSFS_FLAG_HAS_MMAP; + sysfs_addrm_start(&acxt); rc = sysfs_add_one(&acxt, sd, dir_sd); sysfs_addrm_finish(&acxt); diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h index 619250d2d7c1..c05e0ddd0268 100644 --- a/fs/sysfs/sysfs.h +++ b/fs/sysfs/sysfs.h @@ -27,6 +27,7 @@ struct sysfs_elem_symlink { }; struct sysfs_elem_attr { + const struct kernfs_ops *ops; struct sysfs_open_dirent *open; }; @@ -89,6 +90,8 @@ struct sysfs_dirent { #define SYSFS_FLAG_MASK ~SYSFS_TYPE_MASK #define SYSFS_FLAG_NS 0x01000 #define SYSFS_FLAG_REMOVED 0x02000 +#define SYSFS_FLAG_HAS_SEQ_SHOW 0x04000 +#define SYSFS_FLAG_HAS_MMAP 0x08000 static inline unsigned int sysfs_type(struct sysfs_dirent *sd) { diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h index b923052c29d0..97c6c0f91325 100644 --- a/include/linux/kernfs.h +++ b/include/linux/kernfs.h @@ -33,6 +33,32 @@ struct sysfs_open_file { const struct vm_operations_struct *vm_ops; }; +struct kernfs_ops { + /* + * Read is handled by either seq_file or raw_read(). + * + * If seq_show() is present, seq_file path is active. The behavior + * is equivalent to single_open(). @sf->private points to the + * associated sysfs_open_file. + * + * read() is bounced through kernel buffer and a read larger than + * PAGE_SIZE results in partial operation of PAGE_SIZE. + */ + int (*seq_show)(struct seq_file *sf, void *v); + + ssize_t (*read)(struct sysfs_open_file *of, char *buf, size_t bytes, + loff_t off); + + /* + * write() is bounced through kernel buffer and a write larger than + * PAGE_SIZE results in partial operation of PAGE_SIZE. + */ + ssize_t (*write)(struct sysfs_open_file *of, char *buf, size_t bytes, + loff_t off); + + int (*mmap)(struct sysfs_open_file *of, struct vm_area_struct *vma); +}; + #ifdef CONFIG_SYSFS struct sysfs_dirent *kernfs_create_dir_ns(struct sysfs_dirent *parent, |