From fd5a13f4893c8df2a5a3af8599adecb52d05fe89 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 3 Sep 2020 16:22:31 +0200 Subject: [PATCH] proc: add a read_iter method to proc proc_ops This will allow proc files to implement iter read semantics. Signed-off-by: Christoph Hellwig Signed-off-by: Al Viro --- fs/proc/inode.c | 53 ++++++++++++++++++++++++++++++++++++++--- include/linux/proc_fs.h | 1 + 2 files changed, 51 insertions(+), 3 deletions(-) diff --git a/fs/proc/inode.c b/fs/proc/inode.c index 93dd20457375..58c075e2a452 100644 --- a/fs/proc/inode.c +++ b/fs/proc/inode.c @@ -297,6 +297,21 @@ static loff_t proc_reg_llseek(struct file *file, loff_t offset, int whence) return rv; } +static ssize_t proc_reg_read_iter(struct kiocb *iocb, struct iov_iter *iter) +{ + struct proc_dir_entry *pde = PDE(file_inode(iocb->ki_filp)); + ssize_t ret; + + if (pde_is_permanent(pde)) + return pde->proc_ops->proc_read_iter(iocb, iter); + + if (!use_pde(pde)) + return -EIO; + ret = pde->proc_ops->proc_read_iter(iocb, iter); + unuse_pde(pde); + return ret; +} + static ssize_t pde_read(struct proc_dir_entry *pde, struct file *file, char __user *buf, size_t count, loff_t *ppos) { typeof_member(struct proc_ops, proc_read) read; @@ -578,6 +593,18 @@ static const struct file_operations proc_reg_file_ops = { .release = proc_reg_release, }; +static const struct file_operations proc_iter_file_ops = { + .llseek = proc_reg_llseek, + .read_iter = proc_reg_read_iter, + .write = proc_reg_write, + .poll = proc_reg_poll, + .unlocked_ioctl = proc_reg_unlocked_ioctl, + .mmap = proc_reg_mmap, + .get_unmapped_area = proc_reg_get_unmapped_area, + .open = proc_reg_open, + .release = proc_reg_release, +}; + #ifdef CONFIG_COMPAT static const struct file_operations proc_reg_file_ops_compat = { .llseek = proc_reg_llseek, @@ -591,6 +618,19 @@ static const struct file_operations proc_reg_file_ops_compat = { .open = proc_reg_open, .release = proc_reg_release, }; + +static const struct file_operations proc_iter_file_ops_compat = { + .llseek = proc_reg_llseek, + .read_iter = proc_reg_read_iter, + .write = proc_reg_write, + .poll = proc_reg_poll, + .unlocked_ioctl = proc_reg_unlocked_ioctl, + .compat_ioctl = proc_reg_compat_ioctl, + .mmap = proc_reg_mmap, + .get_unmapped_area = proc_reg_get_unmapped_area, + .open = proc_reg_open, + .release = proc_reg_release, +}; #endif static void proc_put_link(void *p) @@ -642,10 +682,17 @@ struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de) if (S_ISREG(inode->i_mode)) { inode->i_op = de->proc_iops; - inode->i_fop = &proc_reg_file_ops; + if (de->proc_ops->proc_read_iter) + inode->i_fop = &proc_iter_file_ops; + else + inode->i_fop = &proc_reg_file_ops; #ifdef CONFIG_COMPAT - if (de->proc_ops->proc_compat_ioctl) - inode->i_fop = &proc_reg_file_ops_compat; + if (de->proc_ops->proc_compat_ioctl) { + if (de->proc_ops->proc_read_iter) + inode->i_fop = &proc_iter_file_ops_compat; + else + inode->i_fop = &proc_reg_file_ops_compat; + } #endif } else if (S_ISDIR(inode->i_mode)) { inode->i_op = de->proc_iops; diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h index 2df965cd0974..270cab43ca3d 100644 --- a/include/linux/proc_fs.h +++ b/include/linux/proc_fs.h @@ -30,6 +30,7 @@ struct proc_ops { unsigned int proc_flags; int (*proc_open)(struct inode *, struct file *); ssize_t (*proc_read)(struct file *, char __user *, size_t, loff_t *); + ssize_t (*proc_read_iter)(struct kiocb *, struct iov_iter *); ssize_t (*proc_write)(struct file *, const char __user *, size_t, loff_t *); loff_t (*proc_lseek)(struct file *, loff_t, int); int (*proc_release)(struct inode *, struct file *);