IMA: convert i_readcount to atomic

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

Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Acked-by: Eric Paris <eparis@redhat.com>

3 files changed, 11 insertions, 10 deletions

diff --git a/include/linux/fs.h b/include/linux/fs.h
index baf3e556ff0..ef85322863b 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -794,8 +794,7 @@ struct inode {
 #endif
 
 #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 c442e47b678..f0053552fd5 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 203de979d30..6e8cb931b8f 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);
         }
 }