drm/xen-front: fix xen_drm_front_shbuf_alloc() error handling

The xen_drm_front_shbuf_alloc() function was returning a mix of error
pointers and NULL and the the caller wasn't checking correctly.  I've
changed it to always return error pointer consistently.

Fixes: c575b7eeb89f ("drm/xen-front: Add support for Xen PV display frontend")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180508092739.GB661@mwanda

diff --git a/drivers/gpu/drm/xen/xen_drm_front.c b/drivers/gpu/drm/xen/xen_drm_front.c
index 8615e85..378cb7c 100644 (file)
--- a/drivers/gpu/drm/xen/xen_drm_front.c
+++ b/drivers/gpu/drm/xen/xen_drm_front.c
@@ -188,8 +188,8 @@ int xen_drm_front_dbuf_create(struct xen_drm_front_info *front_info,
        buf_cfg.be_alloc = front_info->cfg.be_alloc;
 
        shbuf = xen_drm_front_shbuf_alloc(&buf_cfg);
-       if (!shbuf)
-               return -ENOMEM;
+       if (IS_ERR(shbuf))
+               return PTR_ERR(shbuf);
 
        ret = dbuf_add_to_list(front_info, shbuf, dbuf_cookie);
        if (ret < 0) {

diff --git a/drivers/gpu/drm/xen/xen_drm_front_shbuf.c b/drivers/gpu/drm/xen/xen_drm_front_shbuf.c
index d570525..8099cb3 100644 (file)
--- a/drivers/gpu/drm/xen/xen_drm_front_shbuf.c
+++ b/drivers/gpu/drm/xen/xen_drm_front_shbuf.c
@@ -383,7 +383,7 @@ xen_drm_front_shbuf_alloc(struct xen_drm_front_shbuf_cfg *cfg)
 
        buf = kzalloc(sizeof(*buf), GFP_KERNEL);
        if (!buf)
-               return NULL;
+               return ERR_PTR(-ENOMEM);
 
        if (cfg->be_alloc)
                buf->ops = &backend_ops;