[PATCH] drm/bridge: samsung-dsim: Fix memory leak in error path

[Osama Abdelkader <osama.abdelkader@gmail.com>]

In samsung_dsim_host_attach(), drm_bridge_add() is called to add the
bridge. However, if samsung_dsim_register_te_irq() or
pdata->host_ops->attach() fails afterwards, the function returns
without removing the bridge, causing a memory leak.

Fix this by adding proper error handling with goto labels to ensure
drm_bridge_remove() is called in all error paths. Also ensure that
samsung_dsim_unregister_te_irq() is called if the attach operation
fails after the TE IRQ has been registered.

samsung_dsim_unregister_te_irq() function is moved without changes
to be before samsung_dsim_host_attach() to avoid forward declaration.

Fixes: e7447128ca4a ("drm: bridge: Generalize Exynos-DSI driver into a Samsung DSIM bridge")
Cc: stable@vger.kernel.org
Signed-off-by: Osama Abdelkader <osama.abdelkader@gmail.com>
---
v2: 
- Move samsung_dsim_unregister_te_irq() function
- Add Fixes tag
- Add Cc tag
---
 drivers/gpu/drm/bridge/samsung-dsim.c | 25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/samsung-dsim.c
index eabc4c32f6ab..ad8c6aa49d48 100644
--- a/drivers/gpu/drm/bridge/samsung-dsim.c
+++ b/drivers/gpu/drm/bridge/samsung-dsim.c
@@ -1881,6 +1881,14 @@ static int samsung_dsim_register_te_irq(struct samsung_dsim *dsi, struct device
 	return 0;
 }
 
+static void samsung_dsim_unregister_te_irq(struct samsung_dsim *dsi)
+{
+	if (dsi->te_gpio) {
+		free_irq(gpiod_to_irq(dsi->te_gpio), dsi);
+		gpiod_put(dsi->te_gpio);
+	}
+}
+
 static int samsung_dsim_host_attach(struct mipi_dsi_host *host,
 				    struct mipi_dsi_device *device)
 {
@@ -1955,13 +1963,13 @@ static int samsung_dsim_host_attach(struct mipi_dsi_host *host,
 	if (!(device->mode_flags & MIPI_DSI_MODE_VIDEO)) {
 		ret = samsung_dsim_register_te_irq(dsi, &device->dev);
 		if (ret)
-			return ret;
+			goto err_remove_bridge;
 	}
 
 	if (pdata->host_ops && pdata->host_ops->attach) {
 		ret = pdata->host_ops->attach(dsi, device);
 		if (ret)
-			return ret;
+			goto err_unregister_te_irq;
 	}
 
 	dsi->lanes = device->lanes;
@@ -1969,14 +1977,13 @@ static int samsung_dsim_host_attach(struct mipi_dsi_host *host,
 	dsi->mode_flags = device->mode_flags;
 
 	return 0;
-}
 
-static void samsung_dsim_unregister_te_irq(struct samsung_dsim *dsi)
-{
-	if (dsi->te_gpio) {
-		free_irq(gpiod_to_irq(dsi->te_gpio), dsi);
-		gpiod_put(dsi->te_gpio);
-	}
+err_unregister_te_irq:
+	if (!(device->mode_flags & MIPI_DSI_MODE_VIDEO))
+		samsung_dsim_unregister_te_irq(dsi);
+err_remove_bridge:
+	drm_bridge_remove(&dsi->bridge);
+	return ret;
 }
 
 static int samsung_dsim_host_detach(struct mipi_dsi_host *host,
-- 
2.43.0