iiod-client: Use fallback client to destroy blocks and buffers

Allow clients to pass a fallback iiod-client instance to be used when
destroying blocks and buffers.

This is useful because once a buffer is cancelled with
iio_buffer_cancel(), the iiod-client associated with that buffer cannot
be used for data transfers anymore. Using the fallback instance allows
the client to destroy the blocks and buffer properly after the buffer
has been cancelled.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>

iiod-client.c

@@ -48,6 +48,7 @@ static int iiod_client_enable_binary(struct iiod_client *client);
 
 struct iiod_client_buffer_pdata {
 	struct iiod_client *client;
+	struct iiod_client *client_fb;
 	struct iiod_client_io *io;
 
 	struct iio_channels_mask *mask;
@@ -1419,6 +1420,7 @@ ssize_t iiod_client_writebuf(struct iiod_client_buffer_pdata *pdata,
 
 struct iiod_client_buffer_pdata *
 iiod_client_create_buffer(struct iiod_client *client,
+			  struct iiod_client *client_fb,
 			  const struct iio_device *dev, unsigned int idx,
 			  struct iio_channels_mask *mask)
 {
@@ -1435,6 +1437,7 @@ iiod_client_create_buffer(struct iiod_client *client,
 	pdata->dev = dev;
 	pdata->idx = (uint16_t) idx;
 	pdata->client = client;
+	pdata->client_fb = client_fb;
 	pdata->mask = mask;
 
 	if (iiod_client_uses_binary_interface(client)) {
@@ -1462,7 +1465,7 @@ iiod_client_create_buffer(struct iiod_client *client,
 
 void iiod_client_free_buffer(struct iiod_client_buffer_pdata *pdata)
 {
-	struct iiod_client *client = pdata->client;
+	struct iiod_client *client = pdata->client_fb;
 	struct iiod_io *io;
 	struct iiod_command cmd;
 
@@ -1586,7 +1589,7 @@ iiod_client_create_block(struct iiod_client_buffer_pdata *pdata,
 
 void iiod_client_free_block(struct iio_block_pdata *block)
 {
-	struct iiod_client *client = block->buffer->client;
+	struct iiod_client *client = block->buffer->client_fb;
 	struct iiod_io *io;
 	struct iiod_client_buffer_pdata *pdata = block->buffer;
 	struct iiod_command cmd;

include/iio/iiod-client.h

@@ -69,6 +69,7 @@ iiod_client_create_context(struct iiod_client *client,
 
 __api struct iiod_client_buffer_pdata *
 iiod_client_create_buffer(struct iiod_client *client,
+			  struct iiod_client *client_fb,
 			  const struct iio_device *dev, unsigned int idx,
 			  struct iio_channels_mask *mask);
 __api void iiod_client_free_buffer(struct iiod_client_buffer_pdata *pdata);

network.c

@@ -459,8 +459,9 @@ network_create_buffer(const struct iio_device *dev, unsigned int idx,
 		goto err_free_buf;
 	}
 
-	buf->pdata = iiod_client_create_buffer(buf->iiod_client, dev,
-					       idx, mask);
+	buf->pdata = iiod_client_create_buffer(buf->iiod_client,
+					       pdata->iiod_client,
+					       dev, idx, mask);
 	ret = iio_err(buf->pdata);
 	if (ret) {
 		dev_perror(dev, ret, "Unable to create buffer");

serial.c

@@ -239,6 +239,7 @@ serial_create_buffer(const struct iio_device *dev, unsigned int idx,
 		return iio_ptr(-ENOMEM);
 
 	buf->pdata = iiod_client_create_buffer(pdata->iiod_client,
+					       pdata->iiod_client,
 					       dev, idx, mask);
 	ret = iio_err(buf->pdata);
 	if (ret) {

usb.c

@@ -445,6 +445,7 @@ usb_create_buffer(const struct iio_device *dev, unsigned int idx,
 	}
 
 	buf->pdata = iiod_client_create_buffer(buf->io_ctx.iiod_client,
+					       ctx_pdata->io_ctx.iiod_client,
 					       dev, idx, mask);
 	ret = iio_err(buf->pdata);
 	if (ret) {