diff options
| author | KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> | 2010-10-01 14:20:22 -0700 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2010-10-25 21:18:21 -0400 |
| commit | 4a3956c790290efeb647bbb0c3a90476bb57800e (patch) | |
| tree | 18abb41325273d23ae271e49627f01054c5baeb6 /drivers/char/mem.c | |
| parent | ba10f486658c0ca1bc84c936f6a996e40d071453 (diff) | |
| download | lwn-4a3956c790290efeb647bbb0c3a90476bb57800e.tar.gz lwn-4a3956c790290efeb647bbb0c3a90476bb57800e.zip | |
vfs: introduce FMODE_UNSIGNED_OFFSET for allowing negative f_pos
Now, rw_verify_area() checsk f_pos is negative or not. And if negative,
returns -EINVAL.
But, some special files as /dev/(k)mem and /proc/<pid>/mem etc.. has
negative offsets. And we can't do any access via read/write to the
file(device).
So introduce FMODE_UNSIGNED_OFFSET to allow negative file offsets.
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'drivers/char/mem.c')
| -rw-r--r-- | drivers/char/mem.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/char/mem.c b/drivers/char/mem.c index e985b1c2730e..1256454b2d43 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -876,6 +876,10 @@ static int memory_open(struct inode *inode, struct file *filp) if (dev->dev_info) filp->f_mapping->backing_dev_info = dev->dev_info; + /* Is /dev/mem or /dev/kmem ? */ + if (dev->dev_info == &directly_mappable_cdev_bdi) + filp->f_mode |= FMODE_UNSIGNED_OFFSET; + if (dev->fops->open) return dev->fops->open(inode, filp); |