Commit cd28e28d authored by Al Viro's avatar Al Viro
Browse files

switch drivers/char/mem.c to ->read_iter/->write_iter 



Note that _these_ guys have ->read() and ->write() left in place - they are
eqiuvalent to what we'd get if we replaced those with NULL, but we are
talking about hot paths here.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 5d5d5689

drivers/char/mem.c

+9 −9
Original line number Diff line number Diff line
@@ -607,16 +607,16 @@ static ssize_t write_null(struct file *file, const char __user *buf, 
	return count;

}



static ssize_t aio_read_null(struct kiocb *iocb, const struct iovec *iov,

			     unsigned long nr_segs, loff_t pos)

static ssize_t read_iter_null(struct kiocb *iocb, struct iov_iter *to)

{

	return 0;

}



static ssize_t aio_write_null(struct kiocb *iocb, const struct iovec *iov,

			      unsigned long nr_segs, loff_t pos)

static ssize_t write_iter_null(struct kiocb *iocb, struct iov_iter *from)

{

	return iov_length(iov, nr_segs);

	size_t count = iov_iter_count(from);

	iov_iter_advance(from, count);

	return count;

}



static int pipe_to_null(struct pipe_inode_info *info, struct pipe_buffer *buf,
@@ -718,7 +718,7 @@ static int open_port(struct inode *inode, struct file *filp) 
#define zero_lseek	null_lseek

#define full_lseek      null_lseek

#define write_zero	write_null

#define aio_write_zero	aio_write_null

#define write_iter_zero	write_iter_null

#define open_mem	open_port

#define open_kmem	open_mem
@@ -750,8 +750,8 @@ static const struct file_operations null_fops = { 
	.llseek		= null_lseek,

	.read		= read_null,

	.write		= write_null,

	.aio_read	= aio_read_null,

	.aio_write	= aio_write_null,

	.read_iter	= read_iter_null,

	.write_iter	= write_iter_null,

	.splice_write	= splice_write_null,

};
@@ -766,7 +766,7 @@ static const struct file_operations zero_fops = { 
	.llseek		= zero_lseek,

	.write		= write_zero,

	.read_iter	= read_iter_zero,

	.aio_write	= aio_write_zero,

	.write_iter	= write_iter_zero,

	.mmap		= mmap_zero,

#ifndef CONFIG_MMU

	.mmap_capabilities = zero_mmap_capabilities,