Message-Id: <20170628201435.3237712-1-arnd@arndb.de>
Date:   Wed, 28 Jun 2017 22:13:25 +0200
From:   Arnd Bergmann <arnd@...db.de>
To:     Steve Longerbeam <slongerbeam@...il.com>,
        Philipp Zabel <p.zabel@...gutronix.de>,
        Mauro Carvalho Chehab <mchehab@...nel.org>
Cc:     Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Hans Verkuil <hans.verkuil@...co.com>,
        Marek Vasut <marex@...x.de>,
        Russell King <rmk+kernel@...linux.org.uk>,
        linux-media@...r.kernel.org, devel@...verdev.osuosl.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH] [media] staging/imx: remove confusing IS_ERR_OR_NULL usage

While looking at a compiler warning, I noticed the use of
IS_ERR_OR_NULL, which is generally a sign of a bad API design
and should be avoided.

In this driver, this is fairly easy, we can simply stop storing
error pointers in persistent structures, and change the one
function that might return either a NULL pointer or an error
code to consistently return error pointers when failing.

Fixes: e130291212df ("[media] media: Add i.MX media core driver")
Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
I can't reproduce the original warning any more, but this
patch still makes sense by itself.
---
 drivers/staging/media/imx/imx-ic-prpencvf.c | 41 ++++++++++++++++-------------
 drivers/staging/media/imx/imx-media-csi.c   | 29 +++++++++++---------
 drivers/staging/media/imx/imx-media-dev.c   |  2 +-
 drivers/staging/media/imx/imx-media-of.c    |  2 +-
 drivers/staging/media/imx/imx-media-vdic.c  | 37 ++++++++++++++------------
 5 files changed, 61 insertions(+), 50 deletions(-)

diff --git a/drivers/staging/media/imx/imx-ic-prpencvf.c b/drivers/staging/media/imx/imx-ic-prpencvf.c
index ed363fe3b3d0..7a9d9f32f989 100644
--- a/drivers/staging/media/imx/imx-ic-prpencvf.c
+++ b/drivers/staging/media/imx/imx-ic-prpencvf.c
@@ -134,19 +134,19 @@ static inline struct prp_priv *sd_to_priv(struct v4l2_subdev *sd)
 
 static void prp_put_ipu_resources(struct prp_priv *priv)
 {
-	if (!IS_ERR_OR_NULL(priv->ic))
+	if (priv->ic)
 		ipu_ic_put(priv->ic);
 	priv->ic = NULL;
 
-	if (!IS_ERR_OR_NULL(priv->out_ch))
+	if (priv->out_ch)
 		ipu_idmac_put(priv->out_ch);
 	priv->out_ch = NULL;
 
-	if (!IS_ERR_OR_NULL(priv->rot_in_ch))
+	if (priv->rot_in_ch)
 		ipu_idmac_put(priv->rot_in_ch);
 	priv->rot_in_ch = NULL;
 
-	if (!IS_ERR_OR_NULL(priv->rot_out_ch))
+	if (priv->rot_out_ch)
 		ipu_idmac_put(priv->rot_out_ch);
 	priv->rot_out_ch = NULL;
 }
@@ -154,43 +154,46 @@ static void prp_put_ipu_resources(struct prp_priv *priv)
 static int prp_get_ipu_resources(struct prp_priv *priv)
 {
 	struct imx_ic_priv *ic_priv = priv->ic_priv;
+	struct ipu_ic *ic;
+	struct ipuv3_channel *out_ch, *rot_in_ch, *rot_out_ch;
 	int ret, task = ic_priv->task_id;
 
 	priv->ipu = priv->md->ipu[ic_priv->ipu_id];
 
-	priv->ic = ipu_ic_get(priv->ipu, task);
-	if (IS_ERR(priv->ic)) {
+	ic = ipu_ic_get(priv->ipu, task);
+	if (IS_ERR(ic)) {
 		v4l2_err(&ic_priv->sd, "failed to get IC\n");
-		ret = PTR_ERR(priv->ic);
+		ret = PTR_ERR(ic);
 		goto out;
 	}
+	priv->ic = ic;
 
-	priv->out_ch = ipu_idmac_get(priv->ipu,
-				     prp_channel[task].out_ch);
-	if (IS_ERR(priv->out_ch)) {
+	out_ch = ipu_idmac_get(priv->ipu, prp_channel[task].out_ch);
+	if (IS_ERR(out_ch)) {
 		v4l2_err(&ic_priv->sd, "could not get IDMAC channel %u\n",
 			 prp_channel[task].out_ch);
-		ret = PTR_ERR(priv->out_ch);
+		ret = PTR_ERR(out_ch);
 		goto out;
 	}
+	priv->out_ch = out_ch;
 
-	priv->rot_in_ch = ipu_idmac_get(priv->ipu,
-					prp_channel[task].rot_in_ch);
-	if (IS_ERR(priv->rot_in_ch)) {
+	rot_in_ch = ipu_idmac_get(priv->ipu, prp_channel[task].rot_in_ch);
+	if (IS_ERR(rot_in_ch)) {
 		v4l2_err(&ic_priv->sd, "could not get IDMAC channel %u\n",
 			 prp_channel[task].rot_in_ch);
-		ret = PTR_ERR(priv->rot_in_ch);
+		ret = PTR_ERR(rot_in_ch);
 		goto out;
 	}
+	priv->rot_in_ch = rot_in_ch;
 
-	priv->rot_out_ch = ipu_idmac_get(priv->ipu,
-					 prp_channel[task].rot_out_ch);
-	if (IS_ERR(priv->rot_out_ch)) {
+	rot_out_ch = ipu_idmac_get(priv->ipu, prp_channel[task].rot_out_ch);
+	if (IS_ERR(rot_out_ch)) {
 		v4l2_err(&ic_priv->sd, "could not get IDMAC channel %u\n",
 			 prp_channel[task].rot_out_ch);
-		ret = PTR_ERR(priv->rot_out_ch);
+		ret = PTR_ERR(rot_out_ch);
 		goto out;
 	}
+	priv->rot_out_ch = rot_out_ch;
 
 	return 0;
 out:
diff --git a/drivers/staging/media/imx/imx-media-csi.c b/drivers/staging/media/imx/imx-media-csi.c
index a2d26693912e..a4b3c305dcc8 100644
--- a/drivers/staging/media/imx/imx-media-csi.c
+++ b/drivers/staging/media/imx/imx-media-csi.c
@@ -122,11 +122,11 @@ static inline struct csi_priv *sd_to_dev(struct v4l2_subdev *sdev)
 
 static void csi_idmac_put_ipu_resources(struct csi_priv *priv)
 {
-	if (!IS_ERR_OR_NULL(priv->idmac_ch))
+	if (priv->idmac_ch)
 		ipu_idmac_put(priv->idmac_ch);
 	priv->idmac_ch = NULL;
 
-	if (!IS_ERR_OR_NULL(priv->smfc))
+	if (priv->smfc)
 		ipu_smfc_put(priv->smfc);
 	priv->smfc = NULL;
 }
@@ -134,23 +134,26 @@ static void csi_idmac_put_ipu_resources(struct csi_priv *priv)
 static int csi_idmac_get_ipu_resources(struct csi_priv *priv)
 {
 	int ch_num, ret;
+	struct ipu_smfc *smfc, *idmac_ch;
 
 	ch_num = IPUV3_CHANNEL_CSI0 + priv->smfc_id;
 
-	priv->smfc = ipu_smfc_get(priv->ipu, ch_num);
-	if (IS_ERR(priv->smfc)) {
+	smfc = ipu_smfc_get(priv->ipu, ch_num);
+	if (IS_ERR(smfc)) {
 		v4l2_err(&priv->sd, "failed to get SMFC\n");
-		ret = PTR_ERR(priv->smfc);
+		ret = PTR_ERR(smfc);
 		goto out;
 	}
+	priv->smfc = smfc;
 
-	priv->idmac_ch = ipu_idmac_get(priv->ipu, ch_num);
-	if (IS_ERR(priv->idmac_ch)) {
+	idmac_ch = ipu_idmac_get(priv->ipu, ch_num);
+	if (IS_ERR(idmac_ch)) {
 		v4l2_err(&priv->sd, "could not get IDMAC channel %u\n",
 			 ch_num);
-		ret = PTR_ERR(priv->idmac_ch);
+		ret = PTR_ERR(idmac_ch);
 		goto out;
 	}
+	priv->idmac_ch = idmac_ch;
 
 	return 0;
 out:
@@ -1583,6 +1586,7 @@ static int csi_unsubscribe_event(struct v4l2_subdev *sd, struct v4l2_fh *fh,
 static int csi_registered(struct v4l2_subdev *sd)
 {
 	struct csi_priv *priv = v4l2_get_subdevdata(sd);
+	struct ipu_csi *csi;
 	int i, ret;
 	u32 code;
 
@@ -1590,11 +1594,12 @@ static int csi_registered(struct v4l2_subdev *sd)
 	priv->md = dev_get_drvdata(sd->v4l2_dev->dev);
 
 	/* get handle to IPU CSI */
-	priv->csi = ipu_csi_get(priv->ipu, priv->csi_id);
-	if (IS_ERR(priv->csi)) {
+	csi = ipu_csi_get(priv->ipu, priv->csi_id);
+	if (IS_ERR(csi)) {
 		v4l2_err(&priv->sd, "failed to get CSI%d\n", priv->csi_id);
-		return PTR_ERR(priv->csi);
+		return PTR_ERR(csi);
 	}
+	priv->csi = csi;
 
 	for (i = 0; i < CSI_NUM_PADS; i++) {
 		priv->pad[i].flags = (i == CSI_SINK_PAD) ?
@@ -1663,7 +1668,7 @@ static void csi_unregistered(struct v4l2_subdev *sd)
 	if (priv->fim)
 		imx_media_fim_free(priv->fim);
 
-	if (!IS_ERR_OR_NULL(priv->csi))
+	if (priv->csi)
 		ipu_csi_put(priv->csi);
 }
 
diff --git a/drivers/staging/media/imx/imx-media-dev.c b/drivers/staging/media/imx/imx-media-dev.c
index 48cbc7716758..c58ff0831890 100644
--- a/drivers/staging/media/imx/imx-media-dev.c
+++ b/drivers/staging/media/imx/imx-media-dev.c
@@ -91,7 +91,7 @@ imx_media_add_async_subdev(struct imx_media_dev *imxmd,
 	if (imx_media_find_async_subdev(imxmd, np, devname)) {
 		dev_dbg(imxmd->md.dev, "%s: already added %s\n",
 			__func__, np ? np->name : devname);
-		imxsd = NULL;
+		imxsd = ERR_PTR(-EEXIST);
 		goto out;
 	}
 
diff --git a/drivers/staging/media/imx/imx-media-of.c b/drivers/staging/media/imx/imx-media-of.c
index b026fe66467c..4aac42cb79a4 100644
--- a/drivers/staging/media/imx/imx-media-of.c
+++ b/drivers/staging/media/imx/imx-media-of.c
@@ -115,7 +115,7 @@ of_parse_subdev(struct imx_media_dev *imxmd, struct device_node *sd_np,
 
 	/* register this subdev with async notifier */
 	imxsd = imx_media_add_async_subdev(imxmd, sd_np, NULL);
-	if (IS_ERR_OR_NULL(imxsd))
+	if (IS_ERR(imxsd))
 		return imxsd;
 
 	if (is_csi_port) {
diff --git a/drivers/staging/media/imx/imx-media-vdic.c b/drivers/staging/media/imx/imx-media-vdic.c
index 7eabdc4aa79f..433474d58e3e 100644
--- a/drivers/staging/media/imx/imx-media-vdic.c
+++ b/drivers/staging/media/imx/imx-media-vdic.c
@@ -126,15 +126,15 @@ struct vdic_priv {
 
 static void vdic_put_ipu_resources(struct vdic_priv *priv)
 {
-	if (!IS_ERR_OR_NULL(priv->vdi_in_ch_p))
+	if (priv->vdi_in_ch_p)
 		ipu_idmac_put(priv->vdi_in_ch_p);
 	priv->vdi_in_ch_p = NULL;
 
-	if (!IS_ERR_OR_NULL(priv->vdi_in_ch))
+	if (priv->vdi_in_ch)
 		ipu_idmac_put(priv->vdi_in_ch);
 	priv->vdi_in_ch = NULL;
 
-	if (!IS_ERR_OR_NULL(priv->vdi_in_ch_n))
+	if (priv->vdi_in_ch_n)
 		ipu_idmac_put(priv->vdi_in_ch_n);
 	priv->vdi_in_ch_n = NULL;
 
@@ -146,40 +146,43 @@ static void vdic_put_ipu_resources(struct vdic_priv *priv)
 static int vdic_get_ipu_resources(struct vdic_priv *priv)
 {
 	int ret, err_chan;
+	struct ipuv3_channel *ch;
+	struct ipu_vdi *vdi;
 
 	priv->ipu = priv->md->ipu[priv->ipu_id];
 
-	priv->vdi = ipu_vdi_get(priv->ipu);
-	if (IS_ERR(priv->vdi)) {
+	vdi = ipu_vdi_get(priv->ipu);
+	if (IS_ERR(vdi)) {
 		v4l2_err(&priv->sd, "failed to get VDIC\n");
-		ret = PTR_ERR(priv->vdi);
+		ret = PTR_ERR(vdi);
 		goto out;
 	}
+	priv->vdi = vdi;
 
 	if (!priv->csi_direct) {
-		priv->vdi_in_ch_p = ipu_idmac_get(priv->ipu,
-						  IPUV3_CHANNEL_MEM_VDI_PREV);
-		if (IS_ERR(priv->vdi_in_ch_p)) {
+		ch = ipu_idmac_get(priv->ipu, IPUV3_CHANNEL_MEM_VDI_PREV);
+		if (IS_ERR(ch)) {
 			err_chan = IPUV3_CHANNEL_MEM_VDI_PREV;
-			ret = PTR_ERR(priv->vdi_in_ch_p);
+			ret = PTR_ERR(ch);
 			goto out_err_chan;
 		}
+		priv->vdi_in_ch_p = ch;
 
-		priv->vdi_in_ch = ipu_idmac_get(priv->ipu,
-						IPUV3_CHANNEL_MEM_VDI_CUR);
-		if (IS_ERR(priv->vdi_in_ch)) {
+		ch = ipu_idmac_get(priv->ipu, IPUV3_CHANNEL_MEM_VDI_CUR);
+		if (IS_ERR(ch)) {
 			err_chan = IPUV3_CHANNEL_MEM_VDI_CUR;
-			ret = PTR_ERR(priv->vdi_in_ch);
+			ret = PTR_ERR(ch);
 			goto out_err_chan;
 		}
+		priv->vdi_in_ch = ch;
 
-		priv->vdi_in_ch_n = ipu_idmac_get(priv->ipu,
-						  IPUV3_CHANNEL_MEM_VDI_NEXT);
+		ch = ipu_idmac_get(priv->ipu, IPUV3_CHANNEL_MEM_VDI_NEXT);
 		if (IS_ERR(priv->vdi_in_ch_n)) {
 			err_chan = IPUV3_CHANNEL_MEM_VDI_NEXT;
-			ret = PTR_ERR(priv->vdi_in_ch_n);
+			ret = PTR_ERR(ch);
 			goto out_err_chan;
 		}
+		priv->vdi_in_ch_n = ch;
 	}
 
 	return 0;
-- 
2.9.0

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