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authorDmitry Kalinkin <dmitry.kalinkin@gmail.com>2015-02-26 18:53:10 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-03-07 04:03:22 +0300
commitc74a804f115bdedcac72ea52ca33f46cfae3b74f (patch)
tree0e2c88fa7c1c0ba49147594f70d99688e9345c10 /drivers/staging/vme
parent0cd189a42da07c89c809debc1f6a75f5ec0f5c43 (diff)
downloadlinux-c74a804f115bdedcac72ea52ca33f46cfae3b74f.tar.xz
staging: vme: mmap() support for vme_user
We also make sure that user won't be able to reconfigure the window while it is mmap'ed. Signed-off-by: Dmitry Kalinkin <dmitry.kalinkin@gmail.com> Cc: Martyn Welch <martyn.welch@ge.com> Cc: Igor Alekseev <igor.alekseev@itep.ru> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/staging/vme')
-rw-r--r--drivers/staging/vme/devices/vme_user.c85
1 files changed, 85 insertions, 0 deletions
diff --git a/drivers/staging/vme/devices/vme_user.c b/drivers/staging/vme/devices/vme_user.c
index 87318386034b..19ba749bb122 100644
--- a/drivers/staging/vme/devices/vme_user.c
+++ b/drivers/staging/vme/devices/vme_user.c
@@ -17,6 +17,7 @@
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/atomic.h>
#include <linux/cdev.h>
#include <linux/delay.h>
#include <linux/device.h>
@@ -99,6 +100,7 @@ struct image_desc {
struct device *device; /* Sysfs device */
struct vme_resource *resource; /* VME resource */
int users; /* Number of current users */
+ int mmap_count; /* Number of current mmap's */
};
static struct image_desc image[VME_DEVS];
@@ -134,6 +136,10 @@ static ssize_t vme_user_write(struct file *, const char __user *, size_t,
loff_t *);
static loff_t vme_user_llseek(struct file *, loff_t, int);
static long vme_user_unlocked_ioctl(struct file *, unsigned int, unsigned long);
+static int vme_user_mmap(struct file *file, struct vm_area_struct *vma);
+
+static void vme_user_vm_open(struct vm_area_struct *vma);
+static void vme_user_vm_close(struct vm_area_struct *vma);
static int vme_user_match(struct vme_dev *);
static int vme_user_probe(struct vme_dev *);
@@ -147,6 +153,17 @@ static const struct file_operations vme_user_fops = {
.llseek = vme_user_llseek,
.unlocked_ioctl = vme_user_unlocked_ioctl,
.compat_ioctl = vme_user_unlocked_ioctl,
+ .mmap = vme_user_mmap,
+};
+
+struct vme_user_vma_priv {
+ unsigned int minor;
+ atomic_t refcnt;
+};
+
+static const struct vm_operations_struct vme_user_vm_ops = {
+ .open = vme_user_vm_open,
+ .close = vme_user_vm_close,
};
@@ -488,6 +505,11 @@ static int vme_user_ioctl(struct inode *inode, struct file *file,
case VME_SET_MASTER:
+ if (image[minor].mmap_count != 0) {
+ pr_warn("Can't adjust mapped window\n");
+ return -EPERM;
+ }
+
copied = copy_from_user(&master, argp, sizeof(master));
if (copied != 0) {
pr_warn("Partial copy from userspace\n");
@@ -564,6 +586,69 @@ vme_user_unlocked_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
return ret;
}
+static void vme_user_vm_open(struct vm_area_struct *vma)
+{
+ struct vme_user_vma_priv *vma_priv = vma->vm_private_data;
+
+ atomic_inc(&vma_priv->refcnt);
+}
+
+static void vme_user_vm_close(struct vm_area_struct *vma)
+{
+ struct vme_user_vma_priv *vma_priv = vma->vm_private_data;
+ unsigned int minor = vma_priv->minor;
+
+ if (!atomic_dec_and_test(&vma_priv->refcnt))
+ return;
+
+ mutex_lock(&image[minor].mutex);
+ image[minor].mmap_count--;
+ mutex_unlock(&image[minor].mutex);
+
+ kfree(vma_priv);
+}
+
+static int vme_user_master_mmap(unsigned int minor, struct vm_area_struct *vma)
+{
+ int err;
+ struct vme_user_vma_priv *vma_priv;
+
+ mutex_lock(&image[minor].mutex);
+
+ err = vme_master_mmap(image[minor].resource, vma);
+ if (err) {
+ mutex_unlock(&image[minor].mutex);
+ return err;
+ }
+
+ vma_priv = kmalloc(sizeof(struct vme_user_vma_priv), GFP_KERNEL);
+ if (vma_priv == NULL) {
+ mutex_unlock(&image[minor].mutex);
+ return -ENOMEM;
+ }
+
+ vma_priv->minor = minor;
+ atomic_set(&vma_priv->refcnt, 1);
+ vma->vm_ops = &vme_user_vm_ops;
+ vma->vm_private_data = vma_priv;
+
+ image[minor].mmap_count++;
+
+ mutex_unlock(&image[minor].mutex);
+
+ return 0;
+}
+
+static int vme_user_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ unsigned int minor = MINOR(file_inode(file)->i_rdev);
+
+ if (type[minor] == MASTER_MINOR)
+ return vme_user_master_mmap(minor, vma);
+
+ return -ENODEV;
+}
+
/*
* Unallocate a previously allocated buffer