diff options
| author | Thomas Zimmermann <tzimmermann@suse.de> | 2022-04-29 12:08:30 +0200 |
|---|---|---|
| committer | Thomas Zimmermann <tzimmermann@suse.de> | 2022-05-03 16:04:21 +0200 |
| commit | 5905585103276b7c14bb9a7de4b575216cb6dac4 (patch) | |
| tree | b440972605773f8144366c0d96394ce32136f1d2 /drivers/video/fbdev/core/fbmem.c | |
| parent | 594e9c04b5864b4b8b151ef4ba9521c59e0f5c54 (diff) | |
fbdev: Put mmap for deferred I/O into drivers
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@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220429100834.18898-2-tzimmermann@suse.de
Diffstat (limited to 'drivers/video/fbdev/core/fbmem.c')
| -rw-r--r-- | drivers/video/fbdev/core/fbmem.c | 22 |
1 files changed, 12 insertions, 10 deletions
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 } /* |