iio: buffer: rename 'read_first_n' callback to 'read'

It is implied that 'read' will read the first n bytes and not e.g. bytes
only from offsets within the buffer that are a prime number.

This change is non-functional, mostly just a rename.
A secondary intent with this patch is to make room later to add a write
callback.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/buffer/industrialio-buffer-dma.c

@@ -476,7 +476,7 @@ static struct iio_dma_buffer_block *iio_dma_buffer_dequeue(
  * @n: Number of bytes to read
  * @user_buffer: Userspace buffer to copy the data to
  *
- * Should be used as the read_first_n callback for iio_buffer_access_ops
+ * Should be used as the read callback for iio_buffer_access_ops
  * struct for DMA buffers.
  */
 int iio_dma_buffer_read(struct iio_buffer *buffer, size_t n,

drivers/iio/buffer/industrialio-buffer-dmaengine.c

@@ -109,7 +109,7 @@ static void iio_dmaengine_buffer_release(struct iio_buffer *buf)
 }
 
 static const struct iio_buffer_access_funcs iio_dmaengine_buffer_ops = {
-	.read_first_n = iio_dma_buffer_read,
+	.read = iio_dma_buffer_read,
 	.set_bytes_per_datum = iio_dma_buffer_set_bytes_per_datum,
 	.set_length = iio_dma_buffer_set_length,
 	.request_update = iio_dma_buffer_request_update,

drivers/iio/buffer/kfifo_buf.c

@@ -98,8 +98,7 @@ static int iio_store_to_kfifo(struct iio_buffer *r,
 	return 0;
 }
 
-static int iio_read_first_n_kfifo(struct iio_buffer *r,
-			   size_t n, char __user *buf)
+static int iio_read_kfifo(struct iio_buffer *r, size_t n, char __user *buf)
 {
 	int ret, copied;
 	struct iio_kfifo *kf = iio_to_kfifo(r);
@@ -141,7 +140,7 @@ static void iio_kfifo_buffer_release(struct iio_buffer *buffer)
 
 static const struct iio_buffer_access_funcs kfifo_access_funcs = {
 	.store_to = &iio_store_to_kfifo,
-	.read_first_n = &iio_read_first_n_kfifo,
+	.read = &iio_read_kfifo,
 	.data_available = iio_kfifo_buf_data_available,
 	.request_update = &iio_request_update_kfifo,
 	.set_bytes_per_datum = &iio_set_bytes_per_datum_kfifo,

drivers/iio/iio_core.h

@@ -42,14 +42,14 @@ struct poll_table_struct;
 
 __poll_t iio_buffer_poll(struct file *filp,
 			     struct poll_table_struct *wait);
-ssize_t iio_buffer_read_first_n_outer(struct file *filp, char __user *buf,
-				      size_t n, loff_t *f_ps);
+ssize_t iio_buffer_read_outer(struct file *filp, char __user *buf,
+			      size_t n, loff_t *f_ps);
 
 int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev);
 void iio_buffer_free_sysfs_and_mask(struct iio_dev *indio_dev);
 
 #define iio_buffer_poll_addr (&iio_buffer_poll)
-#define iio_buffer_read_first_n_outer_addr (&iio_buffer_read_first_n_outer)
+#define iio_buffer_read_outer_addr (&iio_buffer_read_outer)
 
 void iio_disable_all_buffers(struct iio_dev *indio_dev);
 void iio_buffer_wakeup_poll(struct iio_dev *indio_dev);
@@ -57,7 +57,7 @@ void iio_buffer_wakeup_poll(struct iio_dev *indio_dev);
 #else
 
 #define iio_buffer_poll_addr NULL
-#define iio_buffer_read_first_n_outer_addr NULL
+#define iio_buffer_read_outer_addr NULL
 
 static inline int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev)
 {

drivers/iio/industrialio-buffer.c

@@ -87,7 +87,7 @@ static bool iio_buffer_ready(struct iio_dev *indio_dev, struct iio_buffer *buf,
 }
 
 /**
- * iio_buffer_read_first_n_outer() - chrdev read for buffer access
+ * iio_buffer_read_outer() - chrdev read for buffer access
  * @filp:	File structure pointer for the char device
  * @buf:	Destination buffer for iio buffer read
  * @n:		First n bytes to read
@@ -99,8 +99,8 @@ static bool iio_buffer_ready(struct iio_dev *indio_dev, struct iio_buffer *buf,
  * Return: negative values corresponding to error codes or ret != 0
  *	   for ending the reading activity
  **/
-ssize_t iio_buffer_read_first_n_outer(struct file *filp, char __user *buf,
-				      size_t n, loff_t *f_ps)
+ssize_t iio_buffer_read_outer(struct file *filp, char __user *buf,
+			      size_t n, loff_t *f_ps)
 {
 	struct iio_dev *indio_dev = filp->private_data;
 	struct iio_buffer *rb = indio_dev->buffer;
@@ -112,7 +112,7 @@ ssize_t iio_buffer_read_first_n_outer(struct file *filp, char __user *buf,
 	if (!indio_dev->info)
 		return -ENODEV;
 
-	if (!rb || !rb->access->read_first_n)
+	if (!rb || !rb->access->read)
 		return -EINVAL;
 
 	datum_size = rb->bytes_per_datum;
@@ -147,7 +147,7 @@ ssize_t iio_buffer_read_first_n_outer(struct file *filp, char __user *buf,
 			continue;
 		}
 
-		ret = rb->access->read_first_n(rb, n, buf);
+		ret = rb->access->read(rb, n, buf);
 		if (ret == 0 && (filp->f_flags & O_NONBLOCK))
 			ret = -EAGAIN;
 	} while (ret == 0);

drivers/iio/industrialio-core.c

@@ -1632,7 +1632,7 @@ static long iio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 }
 
 static const struct file_operations iio_buffer_fileops = {
-	.read = iio_buffer_read_first_n_outer_addr,
+	.read = iio_buffer_read_outer_addr,
 	.release = iio_chrdev_release,
 	.open = iio_chrdev_open,
 	.poll = iio_buffer_poll_addr,

include/linux/iio/buffer_impl.h

@@ -18,7 +18,7 @@ struct iio_buffer;
 /**
  * struct iio_buffer_access_funcs - access functions for buffers.
  * @store_to:		actually store stuff to the buffer
- * @read_first_n:	try to get a specified number of bytes (must exist)
+ * @read:		try to get a specified number of bytes (must exist)
  * @data_available:	indicates how much data is available for reading from
  *			the buffer.
  * @request_update:	if a parameter change has been marked, update underlying
@@ -45,9 +45,7 @@ struct iio_buffer;
  **/
 struct iio_buffer_access_funcs {
 	int (*store_to)(struct iio_buffer *buffer, const void *data);
-	int (*read_first_n)(struct iio_buffer *buffer,
-			    size_t n,
-			    char __user *buf);
+	int (*read)(struct iio_buffer *buffer, size_t n, char __user *buf);
 	size_t (*data_available)(struct iio_buffer *buffer);
 
 	int (*request_update)(struct iio_buffer *buffer);