fbdev fixes & cleanups for 7.1-rc3:

- Fix rotating fonts by 180 degrees [Thomas Zimmermann]
 - Drop duplicate include of linux/module.h in fb_defio [Chen Ni]
 - Add vm_ops in udlfb to prevent use-after-free [Rajat Gupta]
 - ipu-v3: clean up kernel-doc warnings [Randy Dunlap]
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Merge tag 'fbdev-for-7.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev

Pull fbdev fixes from Helge Deller:
 "Four small patches for fbdev, of which two are important: One fixes
  the bitmap font generation and the other prevents a possible
  use-after-free in udlfb:

   - Fix rotating fonts by 180 degrees (Thomas Zimmermann)

   - Drop duplicate include of linux/module.h in fb_defio (Chen Ni)

   - Add vm_ops in udlfb to prevent use-after-free (Rajat Gupta)

   - ipu-v3: clean up kernel-doc warnings (Randy Dunlap)"

* tag 'fbdev-for-7.1-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/linux-fbdev:
  fbdev: udlfb: add vm_ops to dlfb_ops_mmap to prevent use-after-free
  lib/fonts: Fix bit position when rotating by 180 degrees
  fbdev: defio: Remove duplicate include of linux/module.h
  fbdev: ipu-v3: clean up kernel-doc warnings

drivers/video/fbdev/core/fb_defio.c

@@ -14,7 +14,6 @@
 #include <linux/export.h>
 #include <linux/string.h>
 #include <linux/mm.h>
-#include <linux/module.h>
 #include <linux/vmalloc.h>
 #include <linux/delay.h>
 #include <linux/interrupt.h>

drivers/video/fbdev/udlfb.c

@@ -321,12 +321,32 @@ static int dlfb_set_video_mode(struct dlfb_data *dlfb,
 	return retval;
 }
 
+static void dlfb_vm_open(struct vm_area_struct *vma)
+{
+	struct dlfb_data *dlfb = vma->vm_private_data;
+
+	atomic_inc(&dlfb->mmap_count);
+}
+
+static void dlfb_vm_close(struct vm_area_struct *vma)
+{
+	struct dlfb_data *dlfb = vma->vm_private_data;
+
+	atomic_dec(&dlfb->mmap_count);
+}
+
+static const struct vm_operations_struct dlfb_vm_ops = {
+	.open  = dlfb_vm_open,
+	.close = dlfb_vm_close,
+};
+
 static int dlfb_ops_mmap(struct fb_info *info, struct vm_area_struct *vma)
 {
 	unsigned long start = vma->vm_start;
 	unsigned long size = vma->vm_end - vma->vm_start;
 	unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
 	unsigned long page, pos;
+	struct dlfb_data *dlfb = info->par;
 
 	if (info->fbdefio)
 		return fb_deferred_io_mmap(info, vma);
@@ -358,6 +378,9 @@ static int dlfb_ops_mmap(struct fb_info *info, struct vm_area_struct *vma)
 			size = 0;
 	}
 
+	vma->vm_ops = &dlfb_vm_ops;
+	vma->vm_private_data = dlfb;
+	atomic_inc(&dlfb->mmap_count);
 	return 0;
 }
 
@@ -1176,7 +1199,6 @@ static void dlfb_deferred_vfree(struct dlfb_data *dlfb, void *mem)
 
 /*
  * Assumes &info->lock held by caller
- * Assumes no active clients have framebuffer open
  */
 static int dlfb_realloc_framebuffer(struct dlfb_data *dlfb, struct fb_info *info, u32 new_len)
 {
@@ -1188,6 +1210,13 @@ static int dlfb_realloc_framebuffer(struct dlfb_data *dlfb, struct fb_info *info
 	new_len = PAGE_ALIGN(new_len);
 
 	if (new_len > old_len) {
+		if (atomic_read(&dlfb->mmap_count) > 0) {
+			dev_warn(info->dev,
+				"refusing realloc: %d active mmaps\n",
+				atomic_read(&dlfb->mmap_count));
+			return -EBUSY;
+		}
+
 		/*
 		 * Alloc system memory for virtual framebuffer
 		 */

include/video/imx-ipu-image-convert.h

@@ -27,12 +27,13 @@ struct ipu_image_convert_run {
 
 	int status;
 
+	/* private: */
 	/* internal to image converter, callers don't touch */
 	struct list_head list;
 };
 
 /**
- * ipu_image_convert_cb_t - conversion callback function prototype
+ * typedef ipu_image_convert_cb_t - conversion callback function prototype
  *
  * @run:	the completed conversion run pointer
  * @ctx:	a private context pointer for the callback
@@ -60,7 +61,7 @@ void ipu_image_convert_adjust(struct ipu_image *in, struct ipu_image *out,
  * @out:	output image format
  * @rot_mode:	rotation mode
  *
- * Returns 0 if the formats and rotation mode meet IPU restrictions,
+ * Returns: 0 if the formats and rotation mode meet IPU restrictions,
  * -EINVAL otherwise.
  */
 int ipu_image_convert_verify(struct ipu_image *in, struct ipu_image *out,
@@ -77,11 +78,11 @@ int ipu_image_convert_verify(struct ipu_image *in, struct ipu_image *out,
  * @complete:	run completion callback
  * @complete_context:	a context pointer for the completion callback
  *
- * Returns an opaque conversion context pointer on success, error pointer
+ * In V4L2, drivers should call ipu_image_convert_prepare() at streamon.
+ *
+ * Returns: an opaque conversion context pointer on success, error pointer
  * on failure. The input/output formats and rotation mode must already meet
  * IPU retrictions.
- *
- * In V4L2, drivers should call ipu_image_convert_prepare() at streamon.
  */
 struct ipu_image_convert_ctx *
 ipu_image_convert_prepare(struct ipu_soc *ipu, enum ipu_ic_task ic_task,
@@ -122,6 +123,8 @@ void ipu_image_convert_unprepare(struct ipu_image_convert_ctx *ctx);
  * In V4L2, drivers should call ipu_image_convert_queue() while
  * streaming to queue the conversion of a received input buffer.
  * For example mem2mem devices this would be called in .device_run.
+ *
+ * Returns: 0 on success or -errno on error.
  */
 int ipu_image_convert_queue(struct ipu_image_convert_run *run);
 
@@ -155,6 +158,9 @@ void ipu_image_convert_abort(struct ipu_image_convert_ctx *ctx);
  * On successful return the caller can queue more run requests if needed, using
  * the prepared context in run->ctx. The caller is responsible for unpreparing
  * the context when no more conversion requests are needed.
+ *
+ * Returns: pointer to the created &struct ipu_image_convert_run that has
+ * been queued on success; an ERR_PTR(errno) on error.
  */
 struct ipu_image_convert_run *
 ipu_image_convert(struct ipu_soc *ipu, enum ipu_ic_task ic_task,

include/video/udlfb.h

@@ -56,6 +56,7 @@ struct dlfb_data {
 	spinlock_t damage_lock;
 	struct work_struct damage_work;
 	struct fb_ops ops;
+	atomic_t mmap_count;
 	/* blit-only rendering path metrics, exposed through sysfs */
 	atomic_t bytes_rendered; /* raw pixel-bytes driver asked to render */
 	atomic_t bytes_identical; /* saved effort with backbuffer comparison */

lib/fonts/font_rotate.c

@@ -106,7 +106,7 @@ static void __font_glyph_rotate_180(const unsigned char *glyph,
 	for (y = 0; y < height; y++) {
 		for (x = 0; x < width; x++) {
 			if (font_glyph_test_bit(glyph, x, y, bit_pitch)) {
-				font_glyph_set_bit(out, width - (1 + x + shift), height - (1 + y),
+				font_glyph_set_bit(out, bit_pitch - 1 - x - shift, height - 1 - y,
 						   bit_pitch);
 			}
 		}