[PATCH v3 2/5] drm/udl: Move drm_dev_{enter, exit}() into udl_get_edid_block()

[Thomas Zimmermann]

Protect the code in udl_get_edid_block() with drm_dev_enter() and
drm_dev_exit(), so that all callers automatically invoke it. The
function uses hardware resources, which can be hot-unplugged at
any time. The other code in udl_connector_detect() does not use the
resources of the hardware device and therefore does not require
protection.

This change will allow to use udl_get_edid_block() in various
contexts easily.

Signed-off-by: Thomas Zimmermann <tzimmerm...@suse.de>
Reviewed-by: Jani Nikula <jani.nik...@intel.com>
---
 drivers/gpu/drm/udl/udl_modeset.c | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/udl/udl_modeset.c 
b/drivers/gpu/drm/udl/udl_modeset.c
index 751da3a294c44..3df9fc38388b4 100644
--- a/drivers/gpu/drm/udl/udl_modeset.c
+++ b/drivers/gpu/drm/udl/udl_modeset.c
@@ -434,13 +434,18 @@ static int udl_get_edid_block(void *data, u8 *buf, 
unsigned int block, size_t le
        struct drm_device *dev = &udl->drm;
        struct usb_device *udev = udl_to_usb_device(udl);
        u8 *read_buff;
-       int ret;
+       int idx, ret;
        size_t i;
 
        read_buff = kmalloc(2, GFP_KERNEL);
        if (!read_buff)
                return -ENOMEM;
 
+       if (!drm_dev_enter(dev, &idx)) {
+               ret = -ENODEV;
+               goto err_kfree;
+       }
+
        for (i = 0; i < len; i++) {
                int bval = (i + block * EDID_LENGTH) << 8;
 
@@ -449,20 +454,23 @@ static int udl_get_edid_block(void *data, u8 *buf, 
unsigned int block, size_t le
                                      0xA1, read_buff, 2, USB_CTRL_GET_TIMEOUT);
                if (ret < 0) {
                        drm_err(dev, "Read EDID byte %zu failed err %x\n", i, 
ret);
-                       goto err_kfree;
+                       goto err_drm_dev_exit;
                } else if (ret < 1) {
                        ret = -EIO;
                        drm_err(dev, "Read EDID byte %zu failed\n", i);
-                       goto err_kfree;
+                       goto err_drm_dev_exit;
                }
 
                buf[i] = read_buff[1];
        }
 
+       drm_dev_exit(idx);
        kfree(read_buff);
 
        return 0;
 
+err_drm_dev_exit:
+       drm_dev_exit(idx);
 err_kfree:
        kfree(read_buff);
        return ret;
@@ -474,21 +482,15 @@ static enum drm_connector_status 
udl_connector_detect(struct drm_connector *conn
        struct udl_device *udl = to_udl(dev);
        struct udl_connector *udl_connector = to_udl_connector(connector);
        enum drm_connector_status status = connector_status_disconnected;
-       int idx;
 
        /* cleanup previous EDID */
        kfree(udl_connector->edid);
        udl_connector->edid = NULL;
 
-       if (!drm_dev_enter(dev, &idx))
-               return connector_status_disconnected;
-
        udl_connector->edid = drm_do_get_edid(connector, udl_get_edid_block, 
udl);
        if (udl_connector->edid)
                status = connector_status_connected;
 
-       drm_dev_exit(idx);
-
        return status;
 }
 
-- 
2.44.0