aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/video/fbmem.c
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2011-05-11 21:58:34 (GMT)
committerLinus Torvalds <torvalds@linux-foundation.org>2011-05-12 14:46:43 (GMT)
commitc47747fde931c02455683bd00ea43eaa62f35b0e (patch)
treea98fbf2b466cabbc71a685a24496e08e074ecfb2 /drivers/video/fbmem.c
parent698b368275c3fa98261159253cfc79653f9dffc6 (diff)
fbmem: make read/write/ioctl use the frame buffer at open time
read/write/ioctl on a fbcon file descriptor has traditionally used the fbcon not when it was opened, but as it was at the time of the call. That makes no sense, but the lack of sense is much more obvious now that we properly ref-count the usage - it means that the ref-counting doesn't actually protect operations we do on the frame buffer. This changes it to look at the fb_info that we got at open time, but in order to avoid using a frame buffer long after it has been unregistered, we do verify that it is still current, and return -ENODEV if not. Acked-by: Tim Gardner <tim.gardner@canonical.com> Tested-by: Daniel J Blueman <daniel.blueman@gmail.com> Tested-by: Anca Emanuel <anca.emanuel@gmail.com> Cc: Bruno Prémont <bonbons@linux-vserver.org> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Dave Airlie <airlied@redhat.com> Cc: Andy Whitcroft <andy.whitcroft@canonical.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/video/fbmem.c')
-rw-r--r--drivers/video/fbmem.c50
1 files changed, 34 insertions, 16 deletions
diff --git a/drivers/video/fbmem.c b/drivers/video/fbmem.c
index eec14d2..ea16e65 100644
--- a/drivers/video/fbmem.c
+++ b/drivers/video/fbmem.c
@@ -717,13 +717,30 @@ static const struct file_operations fb_proc_fops = {
.release = seq_release,
};
-static ssize_t
-fb_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
+/*
+ * We hold a reference to the fb_info in file->private_data,
+ * but if the current registered fb has changed, we don't
+ * actually want to use it.
+ *
+ * So look up the fb_info using the inode minor number,
+ * and just verify it against the reference we have.
+ */
+static struct fb_info *file_fb_info(struct file *file)
{
- unsigned long p = *ppos;
struct inode *inode = file->f_path.dentry->d_inode;
int fbidx = iminor(inode);
struct fb_info *info = registered_fb[fbidx];
+
+ if (info != file->private_data)
+ info = NULL;
+ return info;
+}
+
+static ssize_t
+fb_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
+{
+ unsigned long p = *ppos;
+ struct fb_info *info = file_fb_info(file);
u8 *buffer, *dst;
u8 __iomem *src;
int c, cnt = 0, err = 0;
@@ -788,9 +805,7 @@ static ssize_t
fb_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
{
unsigned long p = *ppos;
- struct inode *inode = file->f_path.dentry->d_inode;
- int fbidx = iminor(inode);
- struct fb_info *info = registered_fb[fbidx];
+ struct fb_info *info = file_fb_info(file);
u8 *buffer, *src;
u8 __iomem *dst;
int c, cnt = 0, err = 0;
@@ -1168,10 +1183,10 @@ static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
static long fb_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
- struct inode *inode = file->f_path.dentry->d_inode;
- int fbidx = iminor(inode);
- struct fb_info *info = registered_fb[fbidx];
+ struct fb_info *info = file_fb_info(file);
+ if (!info)
+ return -ENODEV;
return do_fb_ioctl(info, cmd, arg);
}
@@ -1292,12 +1307,13 @@ static int fb_get_fscreeninfo(struct fb_info *info, unsigned int cmd,
static long fb_compat_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
- struct inode *inode = file->f_path.dentry->d_inode;
- int fbidx = iminor(inode);
- struct fb_info *info = registered_fb[fbidx];
- struct fb_ops *fb = info->fbops;
+ struct fb_info *info = file_fb_info(file);
+ struct fb_ops *fb;
long ret = -ENOIOCTLCMD;
+ if (!info)
+ return -ENODEV;
+ fb = info->fbops;
switch(cmd) {
case FBIOGET_VSCREENINFO:
case FBIOPUT_VSCREENINFO:
@@ -1330,16 +1346,18 @@ static long fb_compat_ioctl(struct file *file, unsigned int cmd,
static int
fb_mmap(struct file *file, struct vm_area_struct * vma)
{
- int fbidx = iminor(file->f_path.dentry->d_inode);
- struct fb_info *info = registered_fb[fbidx];
- struct fb_ops *fb = info->fbops;
+ struct fb_info *info = file_fb_info(file);
+ struct fb_ops *fb;
unsigned long off;
unsigned long start;
u32 len;
+ if (!info)
+ return -ENODEV;
if (vma->vm_pgoff > (~0UL >> PAGE_SHIFT))
return -EINVAL;
off = vma->vm_pgoff << PAGE_SHIFT;
+ fb = info->fbops;
if (!fb)
return -ENODEV;
mutex_lock(&info->mm_lock);

Privacy Policy