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path: root/drivers/char/mem.c
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Diffstat (limited to 'drivers/char/mem.c')
-rw-r--r--drivers/char/mem.c36
1 files changed, 36 insertions, 0 deletions
diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 2c644afbcdd4..1ccbe9482faa 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -28,6 +28,7 @@
#include <linux/pfn.h>
#include <linux/export.h>
#include <linux/io.h>
+#include <linux/aio.h>
#include <asm/uaccess.h>
@@ -627,6 +628,18 @@ 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)
+{
+ return 0;
+}
+
+static ssize_t aio_write_null(struct kiocb *iocb, const struct iovec *iov,
+ unsigned long nr_segs, loff_t pos)
+{
+ return iov_length(iov, nr_segs);
+}
+
static int pipe_to_null(struct pipe_inode_info *info, struct pipe_buffer *buf,
struct splice_desc *sd)
{
@@ -670,6 +683,24 @@ static ssize_t read_zero(struct file *file, char __user *buf,
return written ? written : -EFAULT;
}
+static ssize_t aio_read_zero(struct kiocb *iocb, const struct iovec *iov,
+ unsigned long nr_segs, loff_t pos)
+{
+ size_t written = 0;
+ unsigned long i;
+ ssize_t ret;
+
+ for (i = 0; i < nr_segs; i++) {
+ ret = read_zero(iocb->ki_filp, iov[i].iov_base, iov[i].iov_len,
+ &pos);
+ if (ret < 0)
+ break;
+ written += ret;
+ }
+
+ return written ? written : -EFAULT;
+}
+
static int mmap_zero(struct file *file, struct vm_area_struct *vma)
{
#ifndef CONFIG_MMU
@@ -738,6 +769,7 @@ static int open_port(struct inode *inode, struct file *filp)
#define full_lseek null_lseek
#define write_zero write_null
#define read_full read_zero
+#define aio_write_zero aio_write_null
#define open_mem open_port
#define open_kmem open_mem
#define open_oldmem open_mem
@@ -766,6 +798,8 @@ 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,
.splice_write = splice_write_null,
};
@@ -782,6 +816,8 @@ static const struct file_operations zero_fops = {
.llseek = zero_lseek,
.read = read_zero,
.write = write_zero,
+ .aio_read = aio_read_zero,
+ .aio_write = aio_write_zero,
.mmap = mmap_zero,
};