[v2, 1/4] fbdev/efifb: Replace references to global screen_info by local pointer
Sui Jingfeng
sui.jingfeng at linux.dev
Mon Dec 4 19:53:09 UTC 2023
Hi,
On 2023/12/4 17:27, Thomas Zimmermann wrote:
> Get the global screen_info's address once and access the data via
> this pointer. Limits the use of global state.
>
> Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
> Reviewed-by: Javier Martinez Canillas <javierm at redhat.com>
Reviewed-by: Sui Jingfeng <suijingfeng at loongson.cn>
I have applied the whole series and do a simple test with efifb:
Yeah, still works!
$ dmesg | grep efifb
[ 0.373800] efifb: probing for efifb
[ 0.373816] efifb: framebuffer at 0xe0030000000, using 5120k, total 5120k
[ 0.373818] efifb: mode is 1280x1024x32, linelength=5120, pages=1
[ 0.373820] efifb: scrolling: redraw
[ 0.373821] efifb: Truecolor: size=8:8:8:8, shift=24:16:8:0
> ---
> drivers/video/fbdev/efifb.c | 113 ++++++++++++++++++------------------
> 1 file changed, 58 insertions(+), 55 deletions(-)
>
> diff --git a/drivers/video/fbdev/efifb.c b/drivers/video/fbdev/efifb.c
> index f9b4ddd592ce4..6cbb65bbe1110 100644
> --- a/drivers/video/fbdev/efifb.c
> +++ b/drivers/video/fbdev/efifb.c
> @@ -147,10 +147,9 @@ static bool efifb_bgrt_sanity_check(struct screen_info *si, u32 bmp_width)
> }
> #endif
>
> -static void efifb_show_boot_graphics(struct fb_info *info)
> +static void efifb_show_boot_graphics(struct fb_info *info, struct screen_info *si)
I think, we probably can add a const modifier for the function
which doesn't modify our local the screen_info instance in the future.
static void efifb_show_boot_graphics(struct fb_info *info, const struct screen_info *si)
Since screen_info is mostly used to provide information.
> {
> u32 bmp_width, bmp_height, bmp_pitch, dst_x, y, src_y;
> - struct screen_info *si = &screen_info;
> struct bmp_file_header *file_header;
> struct bmp_dib_header *dib_header;
> void *bgrt_image = NULL;
> @@ -282,7 +281,7 @@ static const struct fb_ops efifb_ops = {
> .fb_setcolreg = efifb_setcolreg,
> };
>
> -static int efifb_setup(char *options)
> +static int efifb_setup(struct screen_info *si, char *options)
> {
> char *this_opt;
>
> @@ -290,16 +289,16 @@ static int efifb_setup(char *options)
> while ((this_opt = strsep(&options, ",")) != NULL) {
> if (!*this_opt) continue;
>
> - efifb_setup_from_dmi(&screen_info, this_opt);
> + efifb_setup_from_dmi(si, this_opt);
>
> if (!strncmp(this_opt, "base:", 5))
> - screen_info.lfb_base = simple_strtoul(this_opt+5, NULL, 0);
> + si->lfb_base = simple_strtoul(this_opt+5, NULL, 0);
> else if (!strncmp(this_opt, "stride:", 7))
> - screen_info.lfb_linelength = simple_strtoul(this_opt+7, NULL, 0) * 4;
> + si->lfb_linelength = simple_strtoul(this_opt+7, NULL, 0) * 4;
> else if (!strncmp(this_opt, "height:", 7))
> - screen_info.lfb_height = simple_strtoul(this_opt+7, NULL, 0);
> + si->lfb_height = simple_strtoul(this_opt+7, NULL, 0);
> else if (!strncmp(this_opt, "width:", 6))
> - screen_info.lfb_width = simple_strtoul(this_opt+6, NULL, 0);
> + si->lfb_width = simple_strtoul(this_opt+6, NULL, 0);
> else if (!strcmp(this_opt, "nowc"))
> mem_flags &= ~EFI_MEMORY_WC;
> else if (!strcmp(this_opt, "nobgrt"))
> @@ -310,15 +309,15 @@ static int efifb_setup(char *options)
> return 0;
> }
>
> -static inline bool fb_base_is_valid(void)
> +static inline bool fb_base_is_valid(struct screen_info *si)
> {
> - if (screen_info.lfb_base)
> + if (si->lfb_base)
> return true;
>
> - if (!(screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE))
> + if (!(si->capabilities & VIDEO_CAPABILITY_64BIT_BASE))
> return false;
>
> - if (screen_info.ext_lfb_base)
> + if (si->ext_lfb_base)
> return true;
>
> return false;
> @@ -329,7 +328,10 @@ static ssize_t name##_show(struct device *dev, \
> struct device_attribute *attr, \
> char *buf) \
> { \
> - return sprintf(buf, fmt "\n", (screen_info.lfb_##name)); \
> + struct screen_info *si = dev_get_platdata(dev); \
> + if (!si) \
> + return -ENODEV; \
> + return sprintf(buf, fmt "\n", (si->lfb_##name)); \
> } \
> static DEVICE_ATTR_RO(name)
>
> @@ -356,6 +358,7 @@ static u64 bar_offset;
>
> static int efifb_probe(struct platform_device *dev)
> {
> + struct screen_info *si = &screen_info;
> struct fb_info *info;
> struct efifb_par *par;
> int err, orientation;
> @@ -365,48 +368,48 @@ static int efifb_probe(struct platform_device *dev)
> char *option = NULL;
> efi_memory_desc_t md;
>
> - if (screen_info.orig_video_isVGA != VIDEO_TYPE_EFI || pci_dev_disabled)
> + if (si->orig_video_isVGA != VIDEO_TYPE_EFI || pci_dev_disabled)
> return -ENODEV;
>
> if (fb_get_options("efifb", &option))
> return -ENODEV;
> - efifb_setup(option);
> + efifb_setup(si, option);
>
> /* We don't get linelength from UGA Draw Protocol, only from
> * EFI Graphics Protocol. So if it's not in DMI, and it's not
> * passed in from the user, we really can't use the framebuffer.
> */
> - if (!screen_info.lfb_linelength)
> + if (!si->lfb_linelength)
> return -ENODEV;
>
> - if (!screen_info.lfb_depth)
> - screen_info.lfb_depth = 32;
> - if (!screen_info.pages)
> - screen_info.pages = 1;
> - if (!fb_base_is_valid()) {
> + if (!si->lfb_depth)
> + si->lfb_depth = 32;
> + if (!si->pages)
> + si->pages = 1;
> + if (!fb_base_is_valid(si)) {
> printk(KERN_DEBUG "efifb: invalid framebuffer address\n");
> return -ENODEV;
> }
> printk(KERN_INFO "efifb: probing for efifb\n");
>
> /* just assume they're all unset if any are */
> - if (!screen_info.blue_size) {
> - screen_info.blue_size = 8;
> - screen_info.blue_pos = 0;
> - screen_info.green_size = 8;
> - screen_info.green_pos = 8;
> - screen_info.red_size = 8;
> - screen_info.red_pos = 16;
> - screen_info.rsvd_size = 8;
> - screen_info.rsvd_pos = 24;
> + if (!si->blue_size) {
> + si->blue_size = 8;
> + si->blue_pos = 0;
> + si->green_size = 8;
> + si->green_pos = 8;
> + si->red_size = 8;
> + si->red_pos = 16;
> + si->rsvd_size = 8;
> + si->rsvd_pos = 24;
> }
Yeah, Here the efifb modified our local screen_info instance, but this is not relevant to your patch.
>
> - efifb_fix.smem_start = screen_info.lfb_base;
> + efifb_fix.smem_start = si->lfb_base;
>
> - if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE) {
> + if (si->capabilities & VIDEO_CAPABILITY_64BIT_BASE) {
> u64 ext_lfb_base;
>
> - ext_lfb_base = (u64)(unsigned long)screen_info.ext_lfb_base << 32;
> + ext_lfb_base = (u64)(unsigned long)si->ext_lfb_base << 32;
> efifb_fix.smem_start |= ext_lfb_base;
> }
>
> @@ -417,10 +420,10 @@ static int efifb_probe(struct platform_device *dev)
> efifb_fix.smem_start = bar_resource->start + bar_offset;
> }
>
> - efifb_defined.bits_per_pixel = screen_info.lfb_depth;
> - efifb_defined.xres = screen_info.lfb_width;
> - efifb_defined.yres = screen_info.lfb_height;
> - efifb_fix.line_length = screen_info.lfb_linelength;
> + efifb_defined.bits_per_pixel = si->lfb_depth;
> + efifb_defined.xres = si->lfb_width;
> + efifb_defined.yres = si->lfb_height;
> + efifb_fix.line_length = si->lfb_linelength;
>
> /* size_vmode -- that is the amount of memory needed for the
> * used video mode, i.e. the minimum amount of
> @@ -430,7 +433,7 @@ static int efifb_probe(struct platform_device *dev)
> /* size_total -- all video memory we have. Used for
> * entries, ressource allocation and bounds
> * checking. */
> - size_total = screen_info.lfb_size;
> + size_total = si->lfb_size;
> if (size_total < size_vmode)
> size_total = size_vmode;
>
> @@ -512,7 +515,7 @@ static int efifb_probe(struct platform_device *dev)
> pr_info("efifb: mode is %dx%dx%d, linelength=%d, pages=%d\n",
> efifb_defined.xres, efifb_defined.yres,
> efifb_defined.bits_per_pixel, efifb_fix.line_length,
> - screen_info.pages);
> + si->pages);
>
> efifb_defined.xres_virtual = efifb_defined.xres;
> efifb_defined.yres_virtual = efifb_fix.smem_len /
> @@ -526,26 +529,26 @@ static int efifb_probe(struct platform_device *dev)
> efifb_defined.left_margin = (efifb_defined.xres / 8) & 0xf8;
> efifb_defined.hsync_len = (efifb_defined.xres / 8) & 0xf8;
>
> - efifb_defined.red.offset = screen_info.red_pos;
> - efifb_defined.red.length = screen_info.red_size;
> - efifb_defined.green.offset = screen_info.green_pos;
> - efifb_defined.green.length = screen_info.green_size;
> - efifb_defined.blue.offset = screen_info.blue_pos;
> - efifb_defined.blue.length = screen_info.blue_size;
> - efifb_defined.transp.offset = screen_info.rsvd_pos;
> - efifb_defined.transp.length = screen_info.rsvd_size;
> + efifb_defined.red.offset = si->red_pos;
> + efifb_defined.red.length = si->red_size;
> + efifb_defined.green.offset = si->green_pos;
> + efifb_defined.green.length = si->green_size;
> + efifb_defined.blue.offset = si->blue_pos;
> + efifb_defined.blue.length = si->blue_size;
> + efifb_defined.transp.offset = si->rsvd_pos;
> + efifb_defined.transp.length = si->rsvd_size;
>
> pr_info("efifb: %s: "
> "size=%d:%d:%d:%d, shift=%d:%d:%d:%d\n",
> "Truecolor",
> - screen_info.rsvd_size,
> - screen_info.red_size,
> - screen_info.green_size,
> - screen_info.blue_size,
> - screen_info.rsvd_pos,
> - screen_info.red_pos,
> - screen_info.green_pos,
> - screen_info.blue_pos);
> + si->rsvd_size,
> + si->red_size,
> + si->green_size,
> + si->blue_size,
> + si->rsvd_pos,
> + si->red_pos,
> + si->green_pos,
> + si->blue_pos);
>
> efifb_fix.ypanstep = 0;
> efifb_fix.ywrapstep = 0;
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