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

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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: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2015-04-03 15:57:04 -04:00
parent 5d5d568975
commit cd28e28d80
1 changed files with 9 additions and 9 deletions
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18
drivers/char/mem.c
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@ -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,