Modifying fb_ops directly to override fb_mmap with fb_deferred_io_mmap
and then resetting it to NULL afterwards causes problems all over the
place. First, it prevents making the fbops member of struct fb_info a
const pointer, which means we can't make struct fb_ops const
anywhere. Second, a few places have to go out of their way to restore
the original fb_mmap pointer that gets reset to NULL.
Since the only user of the fbops->fb_mmap hook is fb_mmap() in fbmem.c,
call fb_deferred_io_mmap() directly when deferred IO is enabled, and
avoid modifying fb_ops altogether.
Simply use info->fbdefio to determine whether deferred IO should be used
or not. This should be accurate enough for all use cases, although
perhaps not pedantically correct.
v2: Simplify considerably by calling fb_deferred_io_mmap() directly
(Daniel, Ville)
Cc: Jaya Kumar <jayalk@xxxxxxxxxxxx>
Cc: linux-fbdev@xxxxxxxxxxxxxxx
Cc: Daniel Vetter <daniel@xxxxxxxx>
Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
---
drivers/video/fbdev/core/fb_defio.c | 3 ---
drivers/video/fbdev/core/fbmem.c | 15 +++++++++++----
2 files changed, 11 insertions(+), 7 deletions(-)
diff --git a/drivers/video/fbdev/core/fb_defio.c b/drivers/video/fbdev/core/fb_defio.c
index 82c20c6047b0..a591d291b231 100644
--- a/drivers/video/fbdev/core/fb_defio.c
+++ b/drivers/video/fbdev/core/fb_defio.c
@@ -171,7 +171,6 @@ int fb_deferred_io_mmap(struct fb_info *info, struct vm_area_struct *vma)
vma->vm_private_data = info;
return 0;
}
-EXPORT_SYMBOL(fb_deferred_io_mmap);
/* workqueue callback */
static void fb_deferred_io_work(struct work_struct *work)
@@ -206,7 +205,6 @@ void fb_deferred_io_init(struct fb_info *info)
BUG_ON(!fbdefio);
mutex_init(&fbdefio->lock);
- info->fbops->fb_mmap = fb_deferred_io_mmap;
INIT_DELAYED_WORK(&info->deferred_work, fb_deferred_io_work);
INIT_LIST_HEAD(&fbdefio->pagelist);
if (fbdefio->delay == 0) /* set a default of 1 s */
@@ -237,7 +235,6 @@ void fb_deferred_io_cleanup(struct fb_info *info)
page->mapping = NULL;
}
- info->fbops->fb_mmap = NULL;
mutex_destroy(&fbdefio->lock);
}
EXPORT_SYMBOL_GPL(fb_deferred_io_cleanup);
diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
index 86b06a599f96..990550930a8e 100644
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -1332,16 +1332,23 @@ static int
fb_mmap(struct file *file, struct vm_area_struct * vma)
{
struct fb_info *info = file_fb_info(file);
- struct fb_ops *fb;
+ int (*fb_mmap_fn)(struct fb_info *info, struct vm_area_struct *vma);
unsigned long mmio_pgoff;
unsigned long start;
u32 len;
if (!info)
return -ENODEV;
- fb = info->fbops;
mutex_lock(&info->mm_lock);
- if (fb->fb_mmap) {
+
+ 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) {
int res;
/*
@@ -1349,7 +1356,7 @@ 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->fb_mmap(info, vma);
+ res = fb_mmap_fn(info, vma);
mutex_unlock(&info->mm_lock);
return res;
}
--
2.20.1
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