From f20ffd938d71b70679c7dbb6b0919f11be505430 Mon Sep 17 00:00:00 2001
From: Paul Cercueil <paul@crapouillou.net>
Date: Fri, 21 May 2021 17:11:42 +0100
Subject: [PATCH] usb.c: Scanning doesn't require context

Remove functions usb_context_scan_init() and usb_context_scan_free(),
as the context structure is not really required; the libusb context can
be created then destroyed in usb_context_scan() directly.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
---
 iio-private.h |  7 +------
 scan.c        | 12 +++++-------
 usb.c         | 45 +++++++++++----------------------------------
 3 files changed, 17 insertions(+), 47 deletions(-)

diff --git a/iio-private.h b/iio-private.h
index 063c32426..5ce458688 100644
--- a/iio-private.h
+++ b/iio-private.h
@@ -124,7 +124,6 @@ static inline __check_ret void * ERR_TO_PTR(intptr_t err)
 struct iio_context_pdata;
 struct iio_device_pdata;
 struct iio_channel_pdata;
-struct iio_scan_backend_context;
 
 struct iio_channel_attr {
 	char *name;
@@ -246,11 +245,7 @@ struct iio_context * serial_create_context_from_uri(const char *uri);
 
 int local_context_scan(struct iio_scan_result *scan_result);
 
-struct iio_scan_backend_context * usb_context_scan_init(void);
-void usb_context_scan_free(struct iio_scan_backend_context *ctx);
-
-int usb_context_scan(struct iio_scan_backend_context *ctx,
-		struct iio_scan_result *scan_result);
+int usb_context_scan(struct iio_scan_result *scan_result);
 
 int dnssd_context_scan(struct iio_scan_result *scan_result);
 
diff --git a/scan.c b/scan.c
index b0ebf416d..925c7f103 100644
--- a/scan.c
+++ b/scan.c
@@ -14,7 +14,7 @@
 #include <string.h>
 
 struct iio_scan_context {
-	struct iio_scan_backend_context *usb_ctx;
+	bool scan_usb;
 	bool scan_network;
 	bool scan_local;
 };
@@ -45,8 +45,8 @@ ssize_t iio_scan_context_get_info_list(struct iio_scan_context *ctx,
 		}
 	}
 
-	if (WITH_USB_BACKEND && ctx->usb_ctx) {
-		int ret = usb_context_scan(ctx->usb_ctx, &scan_result);
+	if (WITH_USB_BACKEND && ctx->scan_usb) {
+		int ret = usb_context_scan(&scan_result);
 		if (ret < 0) {
 			if (scan_result.info)
 				iio_context_info_list_free(scan_result.info);
@@ -135,8 +135,8 @@ struct iio_scan_context * iio_create_scan_context(
 	if (!backend || strstr(backend, "local"))
 		ctx->scan_local = true;
 
-	if (WITH_USB_BACKEND && (!backend || strstr(backend, "usb")))
-		ctx->usb_ctx = usb_context_scan_init();
+	if (!backend || strstr(backend, "usb"))
+		ctx->scan_usb = true;
 
 	if (!backend || strstr(backend, "ip"))
 		ctx->scan_network = true;
@@ -146,8 +146,6 @@ struct iio_scan_context * iio_create_scan_context(
 
 void iio_scan_context_destroy(struct iio_scan_context *ctx)
 {
-	if (WITH_USB_BACKEND && ctx->usb_ctx)
-		usb_context_scan_free(ctx->usb_ctx);
 	free(ctx);
 }
 
diff --git a/usb.c b/usb.c
index 4cd6f1485..8a7210d8b 100644
--- a/usb.c
+++ b/usb.c
@@ -1200,49 +1200,24 @@ static int usb_fill_context_info(struct iio_context_info *info,
 	return 0;
 }
 
-struct iio_scan_backend_context {
-	libusb_context *ctx;
-};
-
-struct iio_scan_backend_context * usb_context_scan_init(void)
-{
-	struct iio_scan_backend_context *ctx;
-	int ret;
-
-	ctx = malloc(sizeof(*ctx));
-	if (!ctx) {
-		errno = ENOMEM;
-		return NULL;
-	}
-
-	ret = libusb_init(&ctx->ctx);
-	if (ret) {
-		free(ctx);
-		errno = (int) libusb_to_errno(ret);
-		return NULL;
-	}
-
-	return ctx;
-}
-
-void usb_context_scan_free(struct iio_scan_backend_context *ctx)
-{
-	libusb_exit(ctx->ctx);
-	free(ctx);
-}
-
-int usb_context_scan(struct iio_scan_backend_context *ctx,
-		struct iio_scan_result *scan_result)
+int usb_context_scan(struct iio_scan_result *scan_result)
 {
 	struct iio_context_info **info;
 	libusb_device **device_list;
+	libusb_context *ctx;
 	unsigned int i;
 	int ret;
 
-	ret = (int) libusb_get_device_list(ctx->ctx, &device_list);
+	ret = libusb_init(&ctx);
 	if (ret < 0)
 		return -(int) libusb_to_errno(ret);
 
+	ret = (int) libusb_get_device_list(ctx, &device_list);
+	if (ret < 0) {
+		ret = -(int) libusb_to_errno(ret);
+		goto cleanup_libusb_exit;
+	}
+
 	for (i = 0; device_list[i]; i++) {
 		struct libusb_device_handle *hdl;
 		struct libusb_device *dev = device_list[i];
@@ -1270,5 +1245,7 @@ int usb_context_scan(struct iio_scan_backend_context *ctx,
 
 cleanup_free_device_list:
 	libusb_free_device_list(device_list, true);
+cleanup_libusb_exit:
+	libusb_exit(ctx);
 	return ret;
 }