From 3e680aae4e53ab54cdbb0c29257dae0cbb158e1c Mon Sep 17 00:00:00 2001 From: Krzysztof Helt Date: Sat, 18 Oct 2008 20:27:51 -0700 Subject: [PATCH] fb: convert lock/unlock_kernel() into local fb mutex Change lock_kernel()/unlock_kernel() to local fb mutex. Each frame buffer instance has its own mutex. The one line try_to_load() function is unrolled to request_module() in two places for readability. [righi.andrea@gmail.com: fb: fix NULL pointer BUG dereference in fb_open()] Signed-off-by: Krzysztof Helt Signed-off-by: Andrea Righi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/video/fbmem.c | 39 ++++++++++++++++++++------------------- include/linux/fb.h | 1 + 2 files changed, 21 insertions(+), 19 deletions(-) diff --git a/drivers/video/fbmem.c b/drivers/video/fbmem.c index 2a0f013dc37..cd5f20da738 100644 --- a/drivers/video/fbmem.c +++ b/drivers/video/fbmem.c @@ -1018,12 +1018,12 @@ fb_ioctl(struct file *file, unsigned int cmd, void __user *argp = (void __user *)arg; long ret = 0; - lock_kernel(); info = registered_fb[fbidx]; + mutex_lock(&info->lock); fb = info->fbops; if (!fb) { - unlock_kernel(); + mutex_unlock(&info->lock); return -ENODEV; } switch (cmd) { @@ -1126,7 +1126,7 @@ fb_ioctl(struct file *file, unsigned int cmd, else ret = fb->fb_ioctl(info, cmd, arg); } - unlock_kernel(); + mutex_unlock(&info->lock); return ret; } @@ -1253,7 +1253,7 @@ fb_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) struct fb_ops *fb = info->fbops; long ret = -ENOIOCTLCMD; - lock_kernel(); + mutex_lock(&info->lock); switch(cmd) { case FBIOGET_VSCREENINFO: case FBIOPUT_VSCREENINFO: @@ -1279,7 +1279,7 @@ fb_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg) ret = fb->fb_compat_ioctl(info, cmd, arg); break; } - unlock_kernel(); + mutex_unlock(&info->lock); return ret; } #endif @@ -1301,13 +1301,13 @@ fb_mmap(struct file *file, struct vm_area_struct * vma) return -ENODEV; if (fb->fb_mmap) { int res; - lock_kernel(); + mutex_lock(&info->lock); res = fb->fb_mmap(info, vma); - unlock_kernel(); + mutex_unlock(&info->lock); return res; } - lock_kernel(); + mutex_lock(&info->lock); /* frame buffer memory */ start = info->fix.smem_start; @@ -1316,13 +1316,13 @@ fb_mmap(struct file *file, struct vm_area_struct * vma) /* memory mapped io */ off -= len; if (info->var.accel_flags) { - unlock_kernel(); + mutex_unlock(&info->lock); return -EINVAL; } start = info->fix.mmio_start; len = PAGE_ALIGN((start & ~PAGE_MASK) + info->fix.mmio_len); } - unlock_kernel(); + mutex_unlock(&info->lock); start &= PAGE_MASK; if ((vma->vm_end - vma->vm_start + off) > len) return -EINVAL; @@ -1346,13 +1346,13 @@ fb_open(struct inode *inode, struct file *file) if (fbidx >= FB_MAX) return -ENODEV; - lock_kernel(); - if (!(info = registered_fb[fbidx])) + info = registered_fb[fbidx]; + if (!info) request_module("fb%d", fbidx); - if (!(info = registered_fb[fbidx])) { - res = -ENODEV; - goto out; - } + info = registered_fb[fbidx]; + if (!info) + return -ENODEV; + mutex_lock(&info->lock); if (!try_module_get(info->fbops->owner)) { res = -ENODEV; goto out; @@ -1368,7 +1368,7 @@ fb_open(struct inode *inode, struct file *file) fb_deferred_io_open(info, inode, file); #endif out: - unlock_kernel(); + mutex_unlock(&info->lock); return res; } @@ -1377,11 +1377,11 @@ fb_release(struct inode *inode, struct file *file) { struct fb_info * const info = file->private_data; - lock_kernel(); + mutex_lock(&info->lock); if (info->fbops->fb_release) info->fbops->fb_release(info,1); module_put(info->fbops->owner); - unlock_kernel(); + mutex_unlock(&info->lock); return 0; } @@ -1460,6 +1460,7 @@ register_framebuffer(struct fb_info *fb_info) if (!registered_fb[i]) break; fb_info->node = i; + mutex_init(&fb_info->lock); fb_info->dev = device_create(fb_class, fb_info->device, MKDEV(FB_MAJOR, i), NULL, "fb%d", i); diff --git a/include/linux/fb.h b/include/linux/fb.h index 531ccd5f596..75a81eaf343 100644 --- a/include/linux/fb.h +++ b/include/linux/fb.h @@ -808,6 +808,7 @@ struct fb_tile_ops { struct fb_info { int node; int flags; + struct mutex lock; /* Lock for open/release/ioctl funcs */ struct fb_var_screeninfo var; /* Current var */ struct fb_fix_screeninfo fix; /* Current fix */ struct fb_monspecs monspecs; /* Current Monitor specs */ -- 2.41.0