[PATCH 069/437] bpf: convert to read/write iterators

[Jens Axboe]

Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
---
 kernel/bpf/bpf_iter.c | 14 +++++++-------
 kernel/bpf/inode.c    |  2 +-
 kernel/bpf/syscall.c  | 18 ++++++++----------
 3 files changed, 16 insertions(+), 18 deletions(-)

diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c
index 112581cf97e7..f2bbe98234df 100644
--- a/kernel/bpf/bpf_iter.c
+++ b/kernel/bpf/bpf_iter.c
@@ -91,10 +91,10 @@ static bool bpf_iter_support_resched(struct seq_file *seq)
  *  . assuming NULL ->llseek()
  *  . stop() may call bpf program, handling potential overflow there
  */
-static ssize_t bpf_seq_read(struct file *file, char __user *buf, size_t size,
-			    loff_t *ppos)
+static ssize_t bpf_seq_read_iter(struct kiocb *iocb, struct iov_iter *to)
 {
-	struct seq_file *seq = file->private_data;
+	struct seq_file *seq = iocb->ki_filp->private_data;
+	size_t size = iov_iter_count(to);
 	size_t n, offs, copied = 0;
 	int err = 0, num_objs = 0;
 	bool can_resched;
@@ -113,7 +113,7 @@ static ssize_t bpf_seq_read(struct file *file, char __user *buf, size_t size,
 
 	if (seq->count) {
 		n = min(seq->count, size);
-		err = copy_to_user(buf, seq->buf + seq->from, n);
+		err = !copy_to_iter_full(seq->buf + seq->from, n, to);
 		if (err) {
 			err = -EFAULT;
 			goto done;
@@ -222,7 +222,7 @@ static ssize_t bpf_seq_read(struct file *file, char __user *buf, size_t size,
 	}
 
 	n = min(seq->count, size);
-	err = copy_to_user(buf, seq->buf, n);
+	err = !copy_to_iter_full(seq->buf, n, to);
 	if (err) {
 		err = -EFAULT;
 		goto done;
@@ -234,7 +234,7 @@ static ssize_t bpf_seq_read(struct file *file, char __user *buf, size_t size,
 	if (!copied)
 		copied = err;
 	else
-		*ppos += copied;
+		iocb->ki_pos += copied;
 	mutex_unlock(&seq->lock);
 	return copied;
 }
@@ -284,7 +284,7 @@ static int iter_release(struct inode *inode, struct file *file)
 const struct file_operations bpf_iter_fops = {
 	.open		= iter_open,
 	.llseek		= no_llseek,
-	.read		= bpf_seq_read,
+	.read_iter	= bpf_seq_read_iter,
 	.release	= iter_release,
 };
 
diff --git a/kernel/bpf/inode.c b/kernel/bpf/inode.c
index af5d2ffadd70..5e35f1eb1dec 100644
--- a/kernel/bpf/inode.c
+++ b/kernel/bpf/inode.c
@@ -313,7 +313,7 @@ static int bpffs_map_release(struct inode *inode, struct file *file)
  */
 static const struct file_operations bpffs_map_fops = {
 	.open		= bpffs_map_open,
-	.read		= seq_read,
+	.read_iter	= seq_read_iter,
 	.release	= bpffs_map_release,
 };
 
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index c287925471f6..385995dc69a0 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -872,8 +872,7 @@ static void bpf_map_show_fdinfo(struct seq_file *m, struct file *filp)
 }
 #endif
 
-static ssize_t bpf_dummy_read(struct file *filp, char __user *buf, size_t siz,
-			      loff_t *ppos)
+static ssize_t bpf_dummy_read(struct kiocb *iocb, struct iov_iter *to)
 {
 	/* We need this handler such that alloc_file() enables
 	 * f_mode with FMODE_CAN_READ.
@@ -881,8 +880,7 @@ static ssize_t bpf_dummy_read(struct file *filp, char __user *buf, size_t siz,
 	return -EINVAL;
 }
 
-static ssize_t bpf_dummy_write(struct file *filp, const char __user *buf,
-			       size_t siz, loff_t *ppos)
+static ssize_t bpf_dummy_write(struct kiocb *iocb, struct iov_iter *to)
 {
 	/* We need this handler such that alloc_file() enables
 	 * f_mode with FMODE_CAN_WRITE.
@@ -991,8 +989,8 @@ const struct file_operations bpf_map_fops = {
 	.show_fdinfo	= bpf_map_show_fdinfo,
 #endif
 	.release	= bpf_map_release,
-	.read		= bpf_dummy_read,
-	.write		= bpf_dummy_write,
+	.read_iter	= bpf_dummy_read,
+	.write_iter	= bpf_dummy_write,
 	.mmap		= bpf_map_mmap,
 	.poll		= bpf_map_poll,
 	.get_unmapped_area = bpf_get_unmapped_area,
@@ -2378,8 +2376,8 @@ const struct file_operations bpf_prog_fops = {
 	.show_fdinfo	= bpf_prog_show_fdinfo,
 #endif
 	.release	= bpf_prog_release,
-	.read		= bpf_dummy_read,
-	.write		= bpf_dummy_write,
+	.read_iter	= bpf_dummy_read,
+	.write_iter	= bpf_dummy_write,
 };
 
 int bpf_prog_new_fd(struct bpf_prog *prog)
@@ -3142,8 +3140,8 @@ static const struct file_operations bpf_link_fops = {
 	.show_fdinfo	= bpf_link_show_fdinfo,
 #endif
 	.release	= bpf_link_release,
-	.read		= bpf_dummy_read,
-	.write		= bpf_dummy_write,
+	.read_iter	= bpf_dummy_read,
+	.write_iter	= bpf_dummy_write,
 };
 
 static int bpf_link_alloc_id(struct bpf_link *link)
-- 
2.43.0