The fbdev mmap function fb_mmap() unconditionally overrides the
driver's implementation if deferred I/O has been activated. This
makes it hard to implement mmap with anything but a vmalloc()'ed
software buffer. That is specifically a problem for DRM, where
video memory is maintained by a memory manager.
Leave the mmap handling to drivers and expect them to call the
helper for deferred I/O by thmeselves.
v4:
* unlock mm_lock in fb_mmap() error path (Dan)
v3:
* fix warning if fb_mmap is missing (kernel test robot)
v2:
* print a helpful error message if the defio setup is
incorrect (Javier)
Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
Reviewed-by: Javier Martinez Canillas <javierm@xxxxxxxxxx>
---
drivers/gpu/drm/drm_fb_helper.c | 4 +++-
drivers/gpu/drm/vmwgfx/vmwgfx_fb.c | 1 +
drivers/hid/hid-picolcd_fb.c | 1 +
drivers/staging/fbtft/fbtft-core.c | 1 +
drivers/video/fbdev/broadsheetfb.c | 1 +
drivers/video/fbdev/core/fb_defio.c | 1 +
drivers/video/fbdev/core/fbmem.c | 22 ++++++++++++----------
drivers/video/fbdev/hecubafb.c | 1 +
drivers/video/fbdev/hyperv_fb.c | 1 +
drivers/video/fbdev/metronomefb.c | 1 +
drivers/video/fbdev/sh_mobile_lcdcfb.c | 6 ++++++
drivers/video/fbdev/smscufx.c | 3 +++
drivers/video/fbdev/ssd1307fb.c | 1 +
drivers/video/fbdev/udlfb.c | 3 +++
drivers/video/fbdev/xen-fbfront.c | 1 +
15 files changed, 37 insertions(+), 11 deletions(-)
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index d265a73313c9..d06ce0e92d66 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -2118,7 +2118,9 @@ static int drm_fbdev_fb_mmap(struct fb_info *info, struct vm_area_struct *vma)
{
struct drm_fb_helper *fb_helper = info->par;
- if (fb_helper->dev->driver->gem_prime_mmap)
+ if (drm_fbdev_use_shadow_fb(fb_helper))
+ return fb_deferred_io_mmap(info, vma);
+ else if (fb_helper->dev->driver->gem_prime_mmap)
return fb_helper->dev->driver->gem_prime_mmap(fb_helper->buffer->gem, vma);
else
return -ENODEV;
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_fb.c b/drivers/gpu/drm/vmwgfx/vmwgfx_fb.c
index adf17c740656..02a4a4fa3da3 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_fb.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_fb.c
@@ -619,6 +619,7 @@ static const struct fb_ops vmw_fb_ops = {
.fb_imageblit = vmw_fb_imageblit,
.fb_pan_display = vmw_fb_pan_display,
.fb_blank = vmw_fb_blank,
+ .fb_mmap = fb_deferred_io_mmap,
};
int vmw_fb_init(struct vmw_private *vmw_priv)
diff --git a/drivers/hid/hid-picolcd_fb.c b/drivers/hid/hid-picolcd_fb.c
index 33c102a60992..78515e6bacf0 100644
--- a/drivers/hid/hid-picolcd_fb.c
+++ b/drivers/hid/hid-picolcd_fb.c
@@ -428,6 +428,7 @@ static const struct fb_ops picolcdfb_ops = {
.fb_imageblit = picolcd_fb_imageblit,
.fb_check_var = picolcd_fb_check_var,
.fb_set_par = picolcd_set_par,
+ .fb_mmap = fb_deferred_io_mmap,
};
diff --git a/drivers/staging/fbtft/fbtft-core.c b/drivers/staging/fbtft/fbtft-core.c
index 9c4d797e7ae4..d4e14f7c9d57 100644
--- a/drivers/staging/fbtft/fbtft-core.c
+++ b/drivers/staging/fbtft/fbtft-core.c
@@ -652,6 +652,7 @@ struct fb_info *fbtft_framebuffer_alloc(struct fbtft_display *display,
fbops->fb_imageblit = fbtft_fb_imageblit;
fbops->fb_setcolreg = fbtft_fb_setcolreg;
fbops->fb_blank = fbtft_fb_blank;
+ fbops->fb_mmap = fb_deferred_io_mmap;
fbdefio->delay = HZ / fps;
fbdefio->sort_pagelist = true;
diff --git a/drivers/video/fbdev/broadsheetfb.c b/drivers/video/fbdev/broadsheetfb.c
index b9054f658838..528bc0902338 100644
--- a/drivers/video/fbdev/broadsheetfb.c
+++ b/drivers/video/fbdev/broadsheetfb.c
@@ -1055,6 +1055,7 @@ static const struct fb_ops broadsheetfb_ops = {
.fb_fillrect = broadsheetfb_fillrect,
.fb_copyarea = broadsheetfb_copyarea,
.fb_imageblit = broadsheetfb_imageblit,
+ .fb_mmap = fb_deferred_io_mmap,
};
static struct fb_deferred_io broadsheetfb_defio = {
diff --git a/drivers/video/fbdev/core/fb_defio.c b/drivers/video/fbdev/core/fb_defio.c
index 6aaf6d0abf39..6924d489a289 100644
--- a/drivers/video/fbdev/core/fb_defio.c
+++ b/drivers/video/fbdev/core/fb_defio.c
@@ -181,6 +181,7 @@ int fb_deferred_io_mmap(struct fb_info *info, struct vm_area_struct *vma)
vma->vm_private_data = info;
return 0;
}
+EXPORT_SYMBOL_GPL(fb_deferred_io_mmap);
/* workqueue callback */
static void fb_deferred_io_work(struct work_struct *work)
diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
index 84427470367b..b445a7a00def 100644
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -1334,7 +1334,6 @@ static int
fb_mmap(struct file *file, struct vm_area_struct * vma)
{
struct fb_info *info = file_fb_info(file);
- int (*fb_mmap_fn)(struct fb_info *info, struct vm_area_struct *vma);
unsigned long mmio_pgoff;
unsigned long start;
u32 len;
@@ -1343,14 +1342,7 @@ fb_mmap(struct file *file, struct vm_area_struct * vma)
return -ENODEV;
mutex_lock(&info->mm_lock);
- fb_mmap_fn = info->fbops->fb_mmap;
-
-#if IS_ENABLED(CONFIG_FB_DEFERRED_IO)
- if (info->fbdefio)
- fb_mmap_fn = fb_deferred_io_mmap;
-#endif
-
- if (fb_mmap_fn) {
+ if (info->fbops->fb_mmap) {
int res;
/*
@@ -1358,9 +1350,19 @@ fb_mmap(struct file *file, struct vm_area_struct * vma)
* SME protection is removed ahead of the call
*/
vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
- res = fb_mmap_fn(info, vma);
+ res = info->fbops->fb_mmap(info, vma);
mutex_unlock(&info->mm_lock);
return res;
+#if IS_ENABLED(CONFIG_FB_DEFERRED_IO)
+ } else if (info->fbdefio) {
+ /*
+ * FB deferred I/O wants you to handle mmap in your drivers. At a
+ * minimum, point struct fb_ops.fb_mmap to fb_deferred_io_mmap().
+ */
+ dev_warn_once(info->dev, "fbdev mmap not set up for deferred I/O.\n");
+ mutex_unlock(&info->mm_lock);
+ return -ENODEV;
+#endif
}
/*
diff --git a/drivers/video/fbdev/hecubafb.c b/drivers/video/fbdev/hecubafb.c
index 00d77105161a..2c483e2cf9ec 100644
--- a/drivers/video/fbdev/hecubafb.c
+++ b/drivers/video/fbdev/hecubafb.c
@@ -204,6 +204,7 @@ static const struct fb_ops hecubafb_ops = {
.fb_fillrect = hecubafb_fillrect,
.fb_copyarea = hecubafb_copyarea,
.fb_imageblit = hecubafb_imageblit,
+ .fb_mmap = fb_deferred_io_mmap,
};
static struct fb_deferred_io hecubafb_defio = {
diff --git a/drivers/video/fbdev/hyperv_fb.c b/drivers/video/fbdev/hyperv_fb.c
index c8e0ea27caf1..d7f6abf827b9 100644
--- a/drivers/video/fbdev/hyperv_fb.c
+++ b/drivers/video/fbdev/hyperv_fb.c
@@ -909,6 +909,7 @@ static const struct fb_ops hvfb_ops = {
.fb_copyarea = hvfb_cfb_copyarea,
.fb_imageblit = hvfb_cfb_imageblit,
.fb_blank = hvfb_blank,
+ .fb_mmap = fb_deferred_io_mmap,
};
diff --git a/drivers/video/fbdev/metronomefb.c b/drivers/video/fbdev/metronomefb.c
index af858dd23ea6..2541f2fe065b 100644
--- a/drivers/video/fbdev/metronomefb.c
+++ b/drivers/video/fbdev/metronomefb.c
@@ -564,6 +564,7 @@ static const struct fb_ops metronomefb_ops = {
.fb_fillrect = metronomefb_fillrect,
.fb_copyarea = metronomefb_copyarea,
.fb_imageblit = metronomefb_imageblit,
+ .fb_mmap = fb_deferred_io_mmap,
};
static struct fb_deferred_io metronomefb_defio = {
diff --git a/drivers/video/fbdev/sh_mobile_lcdcfb.c b/drivers/video/fbdev/sh_mobile_lcdcfb.c
index aa4ebe3192ec..1dc5079e4518 100644
--- a/drivers/video/fbdev/sh_mobile_lcdcfb.c
+++ b/drivers/video/fbdev/sh_mobile_lcdcfb.c
@@ -1483,6 +1483,9 @@ sh_mobile_lcdc_overlay_mmap(struct fb_info *info, struct vm_area_struct *vma)
{
struct sh_mobile_lcdc_overlay *ovl = info->par;
+ if (info->fbdefio)
+ return fb_deferred_io_mmap(info, vma);
+
return dma_mmap_coherent(ovl->channel->lcdc->dev, vma, ovl->fb_mem,
ovl->dma_handle, ovl->fb_size);
}
@@ -1957,6 +1960,9 @@ sh_mobile_lcdc_mmap(struct fb_info *info, struct vm_area_struct *vma)
{
struct sh_mobile_lcdc_chan *ch = info->par;
+ if (info->fbdefio)
+ return fb_deferred_io_mmap(info, vma);
+
return dma_mmap_coherent(ch->lcdc->dev, vma, ch->fb_mem,
ch->dma_handle, ch->fb_size);
}
diff --git a/drivers/video/fbdev/smscufx.c b/drivers/video/fbdev/smscufx.c
index 28768c272b73..9383f8d0914c 100644
--- a/drivers/video/fbdev/smscufx.c
+++ b/drivers/video/fbdev/smscufx.c
@@ -779,6 +779,9 @@ static int ufx_ops_mmap(struct fb_info *info, struct vm_area_struct *vma)
unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
unsigned long page, pos;
+ if (info->fbdefio)
+ return fb_deferred_io_mmap(info, vma);
+
if (vma->vm_pgoff > (~0UL >> PAGE_SHIFT))
return -EINVAL;
if (size > info->fix.smem_len)
diff --git a/drivers/video/fbdev/ssd1307fb.c b/drivers/video/fbdev/ssd1307fb.c
index c6d5df31111d..7547b4628afc 100644
--- a/drivers/video/fbdev/ssd1307fb.c
+++ b/drivers/video/fbdev/ssd1307fb.c
@@ -368,6 +368,7 @@ static const struct fb_ops ssd1307fb_ops = {
.fb_fillrect = ssd1307fb_fillrect,
.fb_copyarea = ssd1307fb_copyarea,
.fb_imageblit = ssd1307fb_imageblit,
+ .fb_mmap = fb_deferred_io_mmap,
};
static void ssd1307fb_deferred_io(struct fb_info *info,
diff --git a/drivers/video/fbdev/udlfb.c b/drivers/video/fbdev/udlfb.c
index b6ec0b8e2b72..9e5a33396ef9 100644
--- a/drivers/video/fbdev/udlfb.c
+++ b/drivers/video/fbdev/udlfb.c
@@ -326,6 +326,9 @@ static int dlfb_ops_mmap(struct fb_info *info, struct vm_area_struct *vma)
unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
unsigned long page, pos;
+ if (info->fbdefio)
+ return fb_deferred_io_mmap(info, vma);
+
if (vma->vm_pgoff > (~0UL >> PAGE_SHIFT))
return -EINVAL;
if (size > info->fix.smem_len)
diff --git a/drivers/video/fbdev/xen-fbfront.c b/drivers/video/fbdev/xen-fbfront.c
index 6826f986da43..6c8846eba2fb 100644
--- a/drivers/video/fbdev/xen-fbfront.c
+++ b/drivers/video/fbdev/xen-fbfront.c
@@ -338,6 +338,7 @@ static const struct fb_ops xenfb_fb_ops = {
.fb_imageblit = xenfb_imageblit,
.fb_check_var = xenfb_check_var,
.fb_set_par = xenfb_set_par,
+ .fb_mmap = fb_deferred_io_mmap,
};
static irqreturn_t xenfb_event_handler(int rq, void *dev_id)
--
2.36.0
