[PATCH v1.2 1/5] IMA: convert i_readcount to atomic

Mimi Zohar
2010-11-02T17:08:53Z

Convert the inode's i_readcount from an unsigned int to atomic.

Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
---
include/linux/fs.h | 3 +--
security/integrity/ima/ima_iint.c | 7 ++++---
security/integrity/ima/ima_main.c | 11 ++++++-----
3 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 334d68a..442fceb 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -787,8 +787,7 @@ struct inode {
unsigned int i_flags;

#ifdef CONFIG_IMA
- /* protected by i_lock */
- unsigned int i_readcount; /* struct files open RO */
+ atomic_t i_readcount; /* struct files open RO */
#endif
atomic_t i_writecount;
#ifdef CONFIG_SECURITY
diff --git a/security/integrity/ima/ima_iint.c b/security/integrity/ima/ima_iint.c
index c442e47..f005355 100644
--- a/security/integrity/ima/ima_iint.c
+++ b/security/integrity/ima/ima_iint.c
@@ -137,10 +137,11 @@ void ima_inode_free(struct inode *inode)
{
struct ima_iint_cache *iint;

- if (inode->i_readcount)
- printk(KERN_INFO "%s: readcount: %u\n", __func__, inode->i_readcount);
+ if (atomic_read(&inode->i_readcount))
+ printk(KERN_INFO "%s: readcount: %u\n", __func__,
+ atomic_read(&inode->i_readcount));

- inode->i_readcount = 0;
+ atomic_set(&inode->i_readcount, 0);

if (!IS_IMA(inode))
return;
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 203de97..a189197 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -113,7 +113,7 @@ void ima_counts_get(struct file *file)
goto out;

if (mode & FMODE_WRITE) {
- if (inode->i_readcount && IS_IMA(inode))
+ if (atomic_read(&inode->i_readcount) && IS_IMA(inode))
send_tomtou = true;
goto out;
}
@@ -127,7 +127,7 @@ void ima_counts_get(struct file *file)
out:
/* remember the vfs deals with i_writecount */
if ((mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
- inode->i_readcount++;
+ atomic_inc(&inode->i_readcount);

spin_unlock(&inode->i_lock);

@@ -149,15 +149,16 @@ static void ima_dec_counts(struct inode *inode, struct file *file)
assert_spin_locked(&inode->i_lock);

if ((mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ) {
- if (unlikely(inode->i_readcount == 0)) {
+ if (unlikely(atomic_read(&inode->i_readcount) == 0)) {
if (!ima_limit_imbalance(file)) {
printk(KERN_INFO "%s: open/free imbalance (r:%u)\n",
- __func__, inode->i_readcount);
+ __func__,
+ atomic_read(&inode->i_readcount));
dump_stack();
}
return;
}
- inode->i_readcount--;
+ atomic_dec(&inode->i_readcount);
}
}

--
1.7.2.2