[PATCH 216/437] misc: lkdtm: convert to read/write iterators

Jens Axboe
2024-04-11T15:37:42Z

drivers/misc/lkdtm/core.c | 40 +++++++++++++++++----------------------
1 file changed, 17 insertions(+), 23 deletions(-)

diff --git a/drivers/misc/lkdtm/core.c b/drivers/misc/lkdtm/core.c
index 5732fd59a227..12f02713f39c 100644
--- a/drivers/misc/lkdtm/core.c
+++ b/drivers/misc/lkdtm/core.c
@@ -27,20 +27,17 @@
#include <linux/slab.h>
#include <linux/debugfs.h>
#include <linux/utsname.h>
+#include <linux/uio.h>

#define DEFAULT_COUNT 10

static int lkdtm_debugfs_open(struct inode *inode, struct file *file);
-static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
- size_t count, loff_t *off);
-static ssize_t direct_entry(struct file *f, const char __user *user_buf,
- size_t count, loff_t *off);
+static ssize_t lkdtm_debugfs_read(struct kiocb *iocb, struct iov_iter *to);
+static ssize_t direct_entry(struct kiocb *iocb, struct iov_iter *from);

#ifdef CONFIG_KPROBES
static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs);
-static ssize_t lkdtm_debugfs_entry(struct file *f,
- const char __user *user_buf,
- size_t count, loff_t *off);
+static ssize_t lkdtm_debugfs_entry(struct kiocb *iocb, struct iov_iter *from);
# define CRASHPOINT_KPROBE(_symbol) \
.kprobe = { \
.symbol_name = (_symbol), \
@@ -64,10 +61,10 @@ struct crashpoint {
{ \
.name = _name, \
.fops = { \
- .read = lkdtm_debugfs_read, \
+ .read_iter= lkdtm_debugfs_read, \
.llseek = generic_file_llseek, \
.open = lkdtm_debugfs_open, \
- .write = CRASHPOINT_WRITE(_symbol) \
+ .write_iter = CRASHPOINT_WRITE(_symbol) \
}, \
CRASHPOINT_KPROBE(_symbol) \
}
@@ -224,12 +221,11 @@ static int lkdtm_kprobe_handler(struct kprobe *kp, struct pt_regs *regs)
return 0;
}

-static ssize_t lkdtm_debugfs_entry(struct file *f,
- const char __user *user_buf,
- size_t count, loff_t *off)
+static ssize_t lkdtm_debugfs_entry(struct kiocb *iocb, struct iov_iter *from)
{
- struct crashpoint *crashpoint = file_inode(f)->i_private;
+ struct crashpoint *crashpoint = file_inode(iocb->ki_filp)->i_private;
const struct crashtype *crashtype = NULL;
+ size_t count = iov_iter_count(from);
char *buf;
int err;

@@ -239,7 +235,7 @@ static ssize_t lkdtm_debugfs_entry(struct file *f,
buf = (char *)__get_free_page(GFP_KERNEL);
if (!buf)
return -ENOMEM;
- if (copy_from_user(buf, user_buf, count)) {
+ if (!copy_from_iter_full(buf, count, from)) {
free_page((unsigned long) buf);
return -EFAULT;
}
@@ -257,15 +253,14 @@ static ssize_t lkdtm_debugfs_entry(struct file *f,
if (err < 0)
return err;

- *off += count;
+ iocb->ki_pos += count;

return count;
}
#endif

/* Generic read callback that just prints out the available crash types */
-static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
- size_t count, loff_t *off)
+static ssize_t lkdtm_debugfs_read(struct kiocb *iocb, struct iov_iter *to)
{
int n, cat, idx;
ssize_t out;
@@ -288,8 +283,7 @@ static ssize_t lkdtm_debugfs_read(struct file *f, char __user *user_buf,
}
buf[n] = '\0';

- out = simple_read_from_buffer(user_buf, count, off,
- buf, n);
+ out = simple_copy_to_iter(buf, &iocb->ki_pos, n, to);
free_page((unsigned long) buf);

return out;
@@ -301,10 +295,10 @@ static int lkdtm_debugfs_open(struct inode *inode, struct file *file)
}

/* Special entry to just crash directly. Available without KPROBEs */
-static ssize_t direct_entry(struct file *f, const char __user *user_buf,
- size_t count, loff_t *off)
+static ssize_t direct_entry(struct kiocb *iocb, struct iov_iter *from)
{
const struct crashtype *crashtype;
+ size_t count = iov_iter_count(from);
char *buf;
int err;

@@ -316,7 +310,7 @@ static ssize_t direct_entry(struct file *f, const char __user *user_buf,
buf = (char *)__get_free_page(GFP_KERNEL);
if (!buf)
return -ENOMEM;
- if (copy_from_user(buf, user_buf, count)) {
+ if (!copy_from_iter_full(buf, count, from)) {
free_page((unsigned long) buf);
return -EFAULT;
}
@@ -331,7 +325,7 @@ static ssize_t direct_entry(struct file *f, const char __user *user_buf,

pr_info("Performing direct entry %s\n", crashtype->name);
err = lkdtm_do_action(crashtype);
- *off += count;
+ iocb->ki_pos += count;

if (err)
return err;
--
2.43.0