fbmem: don't call copy_from/to_user() with mutex held
Avoid calling copy_from/to_user() with fb_info->lock mutex held in fbmem ioctl(). fb_mmap() is called under mm->mmap_sem (A) held, that also acquires fb_info->lock (B); fb_ioctl() takes fb_info->lock (B) and does copy_from/to_user() that might acquire mm->mmap_sem (A), causing a deadlock. NOTE: it doesn't push down the fb_info->lock in each own driver's fb_ioctl(), so there are still potential deadlocks elsewhere. Signed-off-by: Andrea Righi <righi.andrea@gmail.com> Cc: Dave Jones <davej@redhat.com> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Johannes Weiner <hannes@saeurebad.de> Cc: Krzysztof Helt <krzysztof.h1@wp.pl> Cc: Harvey Harrison <harvey.harrison@gmail.com> Cc: Stefan Richter <stefanr@s5r6.in-berlin.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Andrea Righi
Linus Torvalds
Родитель
afd8d0f940
Коммит
1f5e31d7e5
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@ -250,10 +250,6 @@ int fb_set_user_cmap(struct fb_cmap_user *cmap, struct fb_info *info)
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int rc, size = cmap->len * sizeof(u16);
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struct fb_cmap umap;
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if (cmap->start < 0 || (!info->fbops->fb_setcolreg &&
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!info->fbops->fb_setcmap))
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return -EINVAL;
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memset(&umap, 0, sizeof(struct fb_cmap));
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rc = fb_alloc_cmap(&umap, cmap->len, cmap->transp != NULL);
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if (rc)
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@ -262,11 +258,23 @@ int fb_set_user_cmap(struct fb_cmap_user *cmap, struct fb_info *info)
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copy_from_user(umap.green, cmap->green, size) ||
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copy_from_user(umap.blue, cmap->blue, size) ||
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(cmap->transp && copy_from_user(umap.transp, cmap->transp, size))) {
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fb_dealloc_cmap(&umap);
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return -EFAULT;
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rc = -EFAULT;
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goto out;
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}
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umap.start = cmap->start;
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if (!lock_fb_info(info)) {
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rc = -ENODEV;
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goto out;
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}
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if (cmap->start < 0 || (!info->fbops->fb_setcolreg &&
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!info->fbops->fb_setcmap)) {
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rc = -EINVAL;
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goto out1;
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}
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rc = fb_set_cmap(&umap, info);
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out1:
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unlock_fb_info(info);
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out:
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fb_dealloc_cmap(&umap);
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return rc;
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}
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@ -1013,132 +1013,139 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
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struct fb_var_screeninfo var;
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struct fb_fix_screeninfo fix;
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struct fb_con2fbmap con2fb;
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struct fb_cmap cmap_from;
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struct fb_cmap_user cmap;
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struct fb_event event;
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void __user *argp = (void __user *)arg;
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long ret = 0;
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fb = info->fbops;
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if (!fb)
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return -ENODEV;
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switch (cmd) {
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case FBIOGET_VSCREENINFO:
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ret = copy_to_user(argp, &info->var,
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sizeof(var)) ? -EFAULT : 0;
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if (!lock_fb_info(info))
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return -ENODEV;
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var = info->var;
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unlock_fb_info(info);
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ret = copy_to_user(argp, &var, sizeof(var)) ? -EFAULT : 0;
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break;
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case FBIOPUT_VSCREENINFO:
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if (copy_from_user(&var, argp, sizeof(var))) {
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ret = -EFAULT;
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break;
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}
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if (copy_from_user(&var, argp, sizeof(var)))
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return -EFAULT;
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if (!lock_fb_info(info))
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return -ENODEV;
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acquire_console_sem();
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info->flags |= FBINFO_MISC_USEREVENT;
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ret = fb_set_var(info, &var);
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info->flags &= ~FBINFO_MISC_USEREVENT;
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release_console_sem();
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if (ret == 0 && copy_to_user(argp, &var, sizeof(var)))
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unlock_fb_info(info);
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if (!ret && copy_to_user(argp, &var, sizeof(var)))
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ret = -EFAULT;
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break;
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case FBIOGET_FSCREENINFO:
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ret = copy_to_user(argp, &info->fix,
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sizeof(fix)) ? -EFAULT : 0;
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if (!lock_fb_info(info))
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return -ENODEV;
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fix = info->fix;
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unlock_fb_info(info);
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ret = copy_to_user(argp, &fix, sizeof(fix)) ? -EFAULT : 0;
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break;
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case FBIOPUTCMAP:
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if (copy_from_user(&cmap, argp, sizeof(cmap)))
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ret = -EFAULT;
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else
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ret = fb_set_user_cmap(&cmap, info);
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return -EFAULT;
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ret = fb_set_user_cmap(&cmap, info);
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break;
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case FBIOGETCMAP:
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if (copy_from_user(&cmap, argp, sizeof(cmap)))
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ret = -EFAULT;
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else
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ret = fb_cmap_to_user(&info->cmap, &cmap);
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return -EFAULT;
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if (!lock_fb_info(info))
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return -ENODEV;
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cmap_from = info->cmap;
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unlock_fb_info(info);
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ret = fb_cmap_to_user(&cmap_from, &cmap);
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break;
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case FBIOPAN_DISPLAY:
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if (copy_from_user(&var, argp, sizeof(var))) {
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ret = -EFAULT;
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break;
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}
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if (copy_from_user(&var, argp, sizeof(var)))
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return -EFAULT;
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if (!lock_fb_info(info))
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return -ENODEV;
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acquire_console_sem();
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ret = fb_pan_display(info, &var);
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release_console_sem();
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unlock_fb_info(info);
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if (ret == 0 && copy_to_user(argp, &var, sizeof(var)))
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ret = -EFAULT;
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return -EFAULT;
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break;
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case FBIO_CURSOR:
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ret = -EINVAL;
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break;
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case FBIOGET_CON2FBMAP:
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if (copy_from_user(&con2fb, argp, sizeof(con2fb)))
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ret = -EFAULT;
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else if (con2fb.console < 1 || con2fb.console > MAX_NR_CONSOLES)
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ret = -EINVAL;
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else {
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con2fb.framebuffer = -1;
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event.info = info;
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event.data = &con2fb;
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fb_notifier_call_chain(FB_EVENT_GET_CONSOLE_MAP,
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&event);
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ret = copy_to_user(argp, &con2fb,
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sizeof(con2fb)) ? -EFAULT : 0;
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}
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return -EFAULT;
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if (con2fb.console < 1 || con2fb.console > MAX_NR_CONSOLES)
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return -EINVAL;
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con2fb.framebuffer = -1;
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event.data = &con2fb;
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if (!lock_fb_info(info))
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return -ENODEV;
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event.info = info;
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fb_notifier_call_chain(FB_EVENT_GET_CONSOLE_MAP, &event);
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unlock_fb_info(info);
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ret = copy_to_user(argp, &con2fb, sizeof(con2fb)) ? -EFAULT : 0;
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break;
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case FBIOPUT_CON2FBMAP:
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if (copy_from_user(&con2fb, argp, sizeof(con2fb))) {
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ret = -EFAULT;
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break;
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}
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if (con2fb.console < 1 || con2fb.console > MAX_NR_CONSOLES) {
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ret = -EINVAL;
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break;
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}
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if (con2fb.framebuffer < 0 || con2fb.framebuffer >= FB_MAX) {
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ret = -EINVAL;
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break;
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}
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if (copy_from_user(&con2fb, argp, sizeof(con2fb)))
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return -EFAULT;
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if (con2fb.console < 1 || con2fb.console > MAX_NR_CONSOLES)
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return -EINVAL;
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if (con2fb.framebuffer < 0 || con2fb.framebuffer >= FB_MAX)
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return -EINVAL;
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if (!registered_fb[con2fb.framebuffer])
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request_module("fb%d", con2fb.framebuffer);
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if (!registered_fb[con2fb.framebuffer]) {
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ret = -EINVAL;
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break;
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}
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event.info = info;
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event.data = &con2fb;
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if (!lock_fb_info(info))
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return -ENODEV;
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event.info = info;
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ret = fb_notifier_call_chain(FB_EVENT_SET_CONSOLE_MAP,
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&event);
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unlock_fb_info(info);
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break;
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case FBIOBLANK:
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if (!lock_fb_info(info))
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return -ENODEV;
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acquire_console_sem();
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info->flags |= FBINFO_MISC_USEREVENT;
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ret = fb_blank(info, arg);
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info->flags &= ~FBINFO_MISC_USEREVENT;
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release_console_sem();
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break;;
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unlock_fb_info(info);
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break;
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default:
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if (fb->fb_ioctl == NULL)
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ret = -ENOTTY;
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else
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if (!lock_fb_info(info))
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return -ENODEV;
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fb = info->fbops;
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if (fb->fb_ioctl)
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ret = fb->fb_ioctl(info, cmd, arg);
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else
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ret = -ENOTTY;
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unlock_fb_info(info);
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}
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return ret;
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}
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static long fb_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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__acquires(&info->lock)
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__releases(&info->lock)
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{
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struct inode *inode = file->f_path.dentry->d_inode;
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int fbidx = iminor(inode);
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struct fb_info *info;
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long ret;
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struct fb_info *info = registered_fb[fbidx];
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info = registered_fb[fbidx];
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mutex_lock(&info->lock);
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ret = do_fb_ioctl(info, cmd, arg);
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mutex_unlock(&info->lock);
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return ret;
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return do_fb_ioctl(info, cmd, arg);
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}
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#ifdef CONFIG_COMPAT
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@ -1257,8 +1264,6 @@ static int fb_get_fscreeninfo(struct fb_info *info, unsigned int cmd,
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static long fb_compat_ioctl(struct file *file, unsigned int cmd,
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unsigned long arg)
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__acquires(&info->lock)
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__releases(&info->lock)
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{
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struct inode *inode = file->f_path.dentry->d_inode;
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int fbidx = iminor(inode);
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@ -1266,7 +1271,6 @@ __releases(&info->lock)
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struct fb_ops *fb = info->fbops;
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long ret = -ENOIOCTLCMD;
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mutex_lock(&info->lock);
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switch(cmd) {
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case FBIOGET_VSCREENINFO:
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case FBIOPUT_VSCREENINFO:
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@ -1292,7 +1296,6 @@ __releases(&info->lock)
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ret = fb->fb_compat_ioctl(info, cmd, arg);
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break;
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}
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mutex_unlock(&info->lock);
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return ret;
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}
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#endif
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@ -960,6 +960,21 @@ extern struct fb_info *registered_fb[FB_MAX];
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extern int num_registered_fb;
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extern struct class *fb_class;
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static inline int lock_fb_info(struct fb_info *info)
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{
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mutex_lock(&info->lock);
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if (!info->fbops) {
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mutex_unlock(&info->lock);
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return 0;
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}
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return 1;
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}
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static inline void unlock_fb_info(struct fb_info *info)
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{
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mutex_unlock(&info->lock);
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}
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static inline void __fb_pad_aligned_buffer(u8 *dst, u32 d_pitch,
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u8 *src, u32 s_pitch, u32 height)
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{
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