From: Christoph Hellwig hch@lst.de
commit 4eaad21a6ac9865df7f31983232ed5928450458d upstream.
Switch kernfs to implement the read_iter method instead of plain old read to prepare to supporting splice and sendfile again.
Signed-off-by: Christoph Hellwig hch@lst.de Link: https://lore.kernel.org/r/20210120204631.274206-2-hch@lst.de Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/kernfs/file.c | 35 ++++++++++++----------------------- 1 file changed, 12 insertions(+), 23 deletions(-)
--- a/fs/kernfs/file.c +++ b/fs/kernfs/file.c @@ -14,6 +14,7 @@ #include <linux/pagemap.h> #include <linux/sched/mm.h> #include <linux/fsnotify.h> +#include <linux/uio.h>
#include "kernfs-internal.h"
@@ -180,11 +181,10 @@ static const struct seq_operations kernf * it difficult to use seq_file. Implement simplistic custom buffering for * bin files. */ -static ssize_t kernfs_file_direct_read(struct kernfs_open_file *of, - char __user *user_buf, size_t count, - loff_t *ppos) +static ssize_t kernfs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter) { - ssize_t len = min_t(size_t, count, PAGE_SIZE); + struct kernfs_open_file *of = kernfs_of(iocb->ki_filp); + ssize_t len = min_t(size_t, iov_iter_count(iter), PAGE_SIZE); const struct kernfs_ops *ops; char *buf;
@@ -210,7 +210,7 @@ static ssize_t kernfs_file_direct_read(s of->event = atomic_read(&of->kn->attr.open->event); ops = kernfs_ops(of->kn); if (ops->read) - len = ops->read(of, buf, len, *ppos); + len = ops->read(of, buf, len, iocb->ki_pos); else len = -EINVAL;
@@ -220,12 +220,12 @@ static ssize_t kernfs_file_direct_read(s if (len < 0) goto out_free;
- if (copy_to_user(user_buf, buf, len)) { + if (copy_to_iter(buf, len, iter) != len) { len = -EFAULT; goto out_free; }
- *ppos += len; + iocb->ki_pos += len;
out_free: if (buf == of->prealloc_buf) @@ -235,22 +235,11 @@ static ssize_t kernfs_file_direct_read(s return len; }
-/** - * kernfs_fop_read - kernfs vfs read callback - * @file: file pointer - * @user_buf: data to write - * @count: number of bytes - * @ppos: starting offset - */ -static ssize_t kernfs_fop_read(struct file *file, char __user *user_buf, - size_t count, loff_t *ppos) +static ssize_t kernfs_fop_read_iter(struct kiocb *iocb, struct iov_iter *iter) { - struct kernfs_open_file *of = kernfs_of(file); - - if (of->kn->flags & KERNFS_HAS_SEQ_SHOW) - return seq_read(file, user_buf, count, ppos); - else - return kernfs_file_direct_read(of, user_buf, count, ppos); + if (kernfs_of(iocb->ki_filp)->kn->flags & KERNFS_HAS_SEQ_SHOW) + return seq_read_iter(iocb, iter); + return kernfs_file_read_iter(iocb, iter); }
/** @@ -960,7 +949,7 @@ void kernfs_notify(struct kernfs_node *k EXPORT_SYMBOL_GPL(kernfs_notify);
const struct file_operations kernfs_file_fops = { - .read = kernfs_fop_read, + .read_iter = kernfs_fop_read_iter, .write = kernfs_fop_write, .llseek = generic_file_llseek, .mmap = kernfs_fop_mmap,