When a new file is created under msharefs, allocate a new mm_struct
to be associated with it for the lifetime of the file.
The mm_struct will hold the VMAs and pagetables for the mshare region
the file represents.
Signed-off-by: Khalid Aziz <khalid@xxxxxxxxxx>
Signed-off-by: Anthony Yznaga <anthony.yznaga@xxxxxxxxxx>
---
mm/mshare.c | 60 +++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 60 insertions(+)
diff --git a/mm/mshare.c b/mm/mshare.c
index f718b8934cdf..a37849e724e1 100644
--- a/mm/mshare.c
+++ b/mm/mshare.c
@@ -17,6 +17,10 @@
#include <linux/fs_context.h>
#include <uapi/linux/magic.h>
+struct mshare_data {
+ struct mm_struct *mm;
+};
+
struct msharefs_info {
struct dentry *info_dentry;
};
@@ -29,11 +33,51 @@ static const struct file_operations msharefs_file_operations = {
.llseek = no_llseek,
};
+static int
+msharefs_fill_mm(struct inode *inode)
+{
+ struct mm_struct *mm;
+ struct mshare_data *m_data = NULL;
+ int ret = 0;
+
+ mm = mm_alloc();
+ if (!mm) {
+ ret = -ENOMEM;
+ goto err_free;
+ }
+
+ mm->mmap_base = mm->task_size = 0;
+
+ m_data = kzalloc(sizeof(*m_data), GFP_KERNEL);
+ if (!m_data) {
+ ret = -ENOMEM;
+ goto err_free;
+ }
+ m_data->mm = mm;
+ inode->i_private = m_data;
+
+ return 0;
+
+err_free:
+ if (mm)
+ mmput(mm);
+ kfree(m_data);
+ return ret;
+}
+
+static void
+msharefs_delmm(struct mshare_data *m_data)
+{
+ mmput(m_data->mm);
+ kfree(m_data);
+}
+
static struct inode
*msharefs_get_inode(struct mnt_idmap *idmap, struct super_block *sb,
const struct inode *dir, umode_t mode)
{
struct inode *inode = new_inode(sb);
+ int ret;
if (!inode)
return ERR_PTR(-ENOMEM);
@@ -46,6 +90,11 @@ static struct inode
case S_IFREG:
inode->i_op = &msharefs_file_inode_ops;
inode->i_fop = &msharefs_file_operations;
+ ret = msharefs_fill_mm(inode);
+ if (ret) {
+ discard_new_inode(inode);
+ inode = ERR_PTR(ret);
+ }
break;
case S_IFDIR:
inode->i_op = &msharefs_dir_inode_ops;
@@ -141,6 +190,16 @@ static const struct inode_operations msharefs_dir_inode_ops = {
.rename = msharefs_rename,
};
+static void
+mshare_evict_inode(struct inode *inode)
+{
+ struct mshare_data *m_data = inode->i_private;
+
+ if (m_data)
+ msharefs_delmm(m_data);
+ clear_inode(inode);
+}
+
static ssize_t
mshare_info_read(struct file *file, char __user *buf, size_t nbytes,
loff_t *ppos)
@@ -158,6 +217,7 @@ static const struct file_operations mshare_info_ops = {
static const struct super_operations mshare_s_ops = {
.statfs = simple_statfs,
+ .evict_inode = mshare_evict_inode,
};
static int
--
2.43.5
