[PATCH 370/437] drivers/most: convert to read/write iterators

Jens Axboe
2024-04-11T15:42:03Z

drivers/most/most_cdev.c | 50 ++++++++++++++++------------------------
1 file changed, 20 insertions(+), 30 deletions(-)

diff --git a/drivers/most/most_cdev.c b/drivers/most/most_cdev.c
index 3ed8f461e01e..1653f23caef4 100644
--- a/drivers/most/most_cdev.c
+++ b/drivers/most/most_cdev.c
@@ -174,24 +174,22 @@ static int comp_close(struct inode *inode, struct file *filp)

/**
* comp_write - implements the syscall to write to the device
- * @filp: file pointer
- * @buf: pointer to user buffer
- * @count: number of bytes to write
- * @offset: offset from where to start writing
+ * @iocb: metadata for IO
+ * @from: pointer to user buffer
*/
-static ssize_t comp_write(struct file *filp, const char __user *buf,
- size_t count, loff_t *offset)
+static ssize_t comp_write(struct kiocb *iocb, struct iov_iter *from)
{
int ret;
- size_t to_copy, left;
+ size_t to_copy;
struct mbo *mbo = NULL;
- struct comp_channel *c = filp->private_data;
+ struct comp_channel *c = iocb->ki_filp->private_data;
+ size_t count = iov_iter_count(from);

mutex_lock(&c->io_mutex);
while (c->dev && !ch_get_mbo(c, &mbo)) {
mutex_unlock(&c->io_mutex);

- if ((filp->f_flags & O_NONBLOCK))
+ if (iocb->ki_filp->f_flags & O_NONBLOCK)
return -EAGAIN;
if (wait_event_interruptible(c->wq, ch_has_mbo(c) || !c->dev))
return -ERESTARTSYS;
@@ -204,13 +202,13 @@ static ssize_t comp_write(struct file *filp, const char __user *buf,
}

to_copy = min(count, c->cfg->buffer_size - c->mbo_offs);
- left = copy_from_user(mbo->virt_address + c->mbo_offs, buf, to_copy);
- if (left == to_copy) {
+ ret = copy_from_iter(mbo->virt_address + c->mbo_offs, to_copy, from);
+ if (ret != to_copy) {
ret = -EFAULT;
goto unlock;
}

- c->mbo_offs += to_copy - left;
+ c->mbo_offs += ret;
if (c->mbo_offs >= c->cfg->buffer_size ||
c->cfg->data_type == MOST_CH_CONTROL ||
c->cfg->data_type == MOST_CH_ASYNC) {
@@ -219,8 +217,6 @@ static ssize_t comp_write(struct file *filp, const char __user *buf,
c->mbo_offs = 0;
most_submit_mbo(mbo);
}
-
- ret = to_copy - left;
unlock:
mutex_unlock(&c->io_mutex);
return ret;
@@ -228,22 +224,20 @@ static ssize_t comp_write(struct file *filp, const char __user *buf,

/**
* comp_read - implements the syscall to read from the device
- * @filp: file pointer
- * @buf: pointer to user buffer
- * @count: number of bytes to read
- * @offset: offset from where to start reading
+ * @iocb: metadata for IO
+ * @to: pointer to user buffer
*/
-static ssize_t
-comp_read(struct file *filp, char __user *buf, size_t count, loff_t *offset)
+static ssize_t comp_read(struct kiocb *iocb, struct iov_iter *to)
{
- size_t to_copy, not_copied, copied;
+ size_t to_copy, copied;
struct mbo *mbo = NULL;
- struct comp_channel *c = filp->private_data;
+ struct comp_channel *c = iocb->ki_filp->private_data;
+ size_t count = iov_iter_count(to);

mutex_lock(&c->io_mutex);
while (c->dev && !kfifo_peek(&c->fifo, &mbo)) {
mutex_unlock(&c->io_mutex);
- if (filp->f_flags & O_NONBLOCK)
+ if (iocb->ki_filp->f_flags & O_NONBLOCK)
return -EAGAIN;
if (wait_event_interruptible(c->wq,
(!kfifo_is_empty(&c->fifo) ||
@@ -262,11 +256,7 @@ comp_read(struct file *filp, char __user *buf, size_t count, loff_t *offset)
count,
mbo->processed_length - c->mbo_offs);

- not_copied = copy_to_user(buf,
- mbo->virt_address + c->mbo_offs,
- to_copy);
-
- copied = to_copy - not_copied;
+ copied = copy_to_iter(mbo->virt_address + c->mbo_offs, to_copy, to);

c->mbo_offs += copied;
if (c->mbo_offs >= mbo->processed_length) {
@@ -302,8 +292,8 @@ static __poll_t comp_poll(struct file *filp, poll_table *wait)
*/
static const struct file_operations channel_fops = {
.owner = THIS_MODULE,
- .read = comp_read,
- .write = comp_write,
+ .read_iter = comp_read,
+ .write_iter = comp_write,
.open = comp_open,
.release = comp_close,
.poll = comp_poll,
--
2.43.0