media: imx: imx7_mipi_csis: Minimize locking in get/set format

Reduce the code sections that are run with the lock held in the get/set
format handlers:

- mipi_csis_get_format() retrieves a pointer to the format, and thus
  doesn't need locking as long as the arguments passed to the function
  don't require locking either.

- sdformat is a structure passed by the caller, not an internal state,
  and thus doesn't require locking.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Rui Miguel Silva <rmfrfs@gmail.com>
Tested-by: Frieder Schrempf <frieder.schrempf@kontron.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

diff --git a/drivers/staging/media/imx/imx7-mipi-csis.c b/drivers/staging/media/imx/imx7-mipi-csis.c
index 1697d8740241951ffd804082cab9c3a929be0a25..f195c65563e726cc1bc176c42eafd70f6a67b7e6 100644 (file)
--- a/drivers/staging/media/imx/imx7-mipi-csis.c
+++ b/drivers/staging/media/imx/imx7-mipi-csis.c
@@ -859,8 +859,9 @@ static int mipi_csis_get_fmt(struct v4l2_subdev *mipi_sd,
        struct csi_state *state = mipi_sd_to_csis_state(mipi_sd);
        struct v4l2_mbus_framefmt *fmt;
 
-       mutex_lock(&state->lock);
        fmt = mipi_csis_get_format(state, cfg, sdformat->which, sdformat->pad);
+
+       mutex_lock(&state->lock);
        sdformat->format = *fmt;
        mutex_unlock(&state->lock);
 
@@ -918,24 +919,17 @@ static int mipi_csis_set_fmt(struct v4l2_subdev *mipi_sd,
        if (sdformat->pad != CSIS_PAD_SINK)
                return -EINVAL;
 
-       fmt = mipi_csis_get_format(state, cfg, sdformat->which, sdformat->pad);
-
-       mutex_lock(&state->lock);
-
-       /* Validate the media bus code and clamp the size. */
-       csis_fmt = find_csis_format(sdformat->format.code);
-       if (!csis_fmt)
-               csis_fmt = &mipi_csis_formats[0];
-
-       fmt->code = csis_fmt->code;
-       fmt->width = sdformat->format.width;
-       fmt->height = sdformat->format.height;
-
        /*
+        * Validate the media bus code and clamp and align the size.
+        *
         * The total number of bits per line must be a multiple of 8. We thus
         * need to align the width for formats that are not multiples of 8
         * bits.
         */
+       csis_fmt = find_csis_format(sdformat->format.code);
+       if (!csis_fmt)
+               csis_fmt = &mipi_csis_formats[0];
+
        switch (csis_fmt->width % 8) {
        case 0:
                align = 0;
@@ -955,8 +949,18 @@ static int mipi_csis_set_fmt(struct v4l2_subdev *mipi_sd,
                break;
        }
 
-       v4l_bound_align_image(&fmt->width, 1, CSIS_MAX_PIX_WIDTH, align,
-                             &fmt->height, 1, CSIS_MAX_PIX_HEIGHT, 0, 0);
+       v4l_bound_align_image(&sdformat->format.width, 1,
+                             CSIS_MAX_PIX_WIDTH, align,
+                             &sdformat->format.height, 1,
+                             CSIS_MAX_PIX_HEIGHT, 0, 0);
+
+       fmt = mipi_csis_get_format(state, cfg, sdformat->which, sdformat->pad);
+
+       mutex_lock(&state->lock);
+
+       fmt->code = csis_fmt->code;
+       fmt->width = sdformat->format.width;
+       fmt->height = sdformat->format.height;
 
        sdformat->format = *fmt;