[PATCH] use simple_read_from_buffer in selinuxfs

Use simple_read_from_buffer.  This also eliminates page allocation for the
sprintf buffer.  Switch to get_zeroed_page instead of open-coding it.  Viro
had ack'd this earlier.  Still applies w/ the transaction update.

Signed-off-by: Chris Wright <chrisw@osdl.org>
Signed-off-by: Stephen Smalley <sds@epoch.ncsc.mil>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c
index e226a991703cd21fb8c3be6966e58d85acf0fa24..a59ce9d3604af52bea7e9c5b5cbb03750d4363ca 100644 (file)
--- a/security/selinux/selinuxfs.c
+++ b/security/selinux/selinuxfs.c
@@ -68,40 +68,15 @@ enum sel_inos {
        SEL_DISABLE     /* disable SELinux until next reboot */
 };
 
+#define TMPBUFLEN      12
 static ssize_t sel_read_enforce(struct file *filp, char __user *buf,
                                size_t count, loff_t *ppos)
 {
-       char *page;
+       char tmpbuf[TMPBUFLEN];
        ssize_t length;
-       ssize_t end;
-
-       if (count < 0 || count > PAGE_SIZE)
-               return -EINVAL;
-       if (!(page = (char*)__get_free_page(GFP_KERNEL)))
-               return -ENOMEM;
-       memset(page, 0, PAGE_SIZE);
 
-       length = scnprintf(page, PAGE_SIZE, "%d", selinux_enforcing);
-       if (length < 0) {
-               free_page((unsigned long)page);
-               return length;
-       }
-
-       if (*ppos >= length) {
-               free_page((unsigned long)page);
-               return 0;
-       }
-       if (count + *ppos > length)
-               count = length - *ppos;
-       end = count + *ppos;
-       if (copy_to_user(buf, (char *) page + *ppos, count)) {
-               count = -EFAULT;
-               goto out;
-       }
-       *ppos = end;
-out:
-       free_page((unsigned long)page);
-       return count;
+       length = scnprintf(tmpbuf, TMPBUFLEN, "%d", selinux_enforcing);
+       return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
 }
 
 #ifdef CONFIG_SECURITY_SELINUX_DEVELOP
@@ -119,10 +94,9 @@ static ssize_t sel_write_enforce(struct file * file, const char __user * buf,
                /* No partial writes. */
                return -EINVAL;
        }
-       page = (char*)__get_free_page(GFP_KERNEL);
+       page = (char*)get_zeroed_page(GFP_KERNEL);
        if (!page)
                return -ENOMEM;
-       memset(page, 0, PAGE_SIZE);
        length = -EFAULT;
        if (copy_from_user(page, buf, count))
                goto out;
@@ -170,10 +144,9 @@ static ssize_t sel_write_disable(struct file * file, const char __user * buf,
                /* No partial writes. */
                return -EINVAL;
        }
-       page = (char*)__get_free_page(GFP_KERNEL);
+       page = (char*)get_zeroed_page(GFP_KERNEL);
        if (!page)
                return -ENOMEM;
-       memset(page, 0, PAGE_SIZE);
        length = -EFAULT;
        if (copy_from_user(page, buf, count))
                goto out;
@@ -204,37 +177,11 @@ static struct file_operations sel_disable_ops = {
 static ssize_t sel_read_policyvers(struct file *filp, char __user *buf,
                                    size_t count, loff_t *ppos)
 {
-       char *page;
+       char tmpbuf[TMPBUFLEN];
        ssize_t length;
-       ssize_t end;
 
-       if (count < 0 || count > PAGE_SIZE)
-               return -EINVAL;
-       if (!(page = (char*)__get_free_page(GFP_KERNEL)))
-               return -ENOMEM;
-       memset(page, 0, PAGE_SIZE);
-
-       length = scnprintf(page, PAGE_SIZE, "%u", POLICYDB_VERSION_MAX);
-       if (length < 0) {
-               free_page((unsigned long)page);
-               return length;
-       }
-
-       if (*ppos >= length) {
-               free_page((unsigned long)page);
-               return 0;
-       }
-       if (count + *ppos > length)
-               count = length - *ppos;
-       end = count + *ppos;
-       if (copy_to_user(buf, (char *) page + *ppos, count)) {
-               count = -EFAULT;
-               goto out;
-       }
-       *ppos = end;
-out:
-       free_page((unsigned long)page);
-       return count;
+       length = scnprintf(tmpbuf, TMPBUFLEN, "%u", POLICYDB_VERSION_MAX);
+       return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
 }
 
 static struct file_operations sel_policyvers_ops = {
@@ -247,37 +194,11 @@ static int sel_make_bools(void);
 static ssize_t sel_read_mls(struct file *filp, char __user *buf,
                                size_t count, loff_t *ppos)
 {
-       char *page;
+       char tmpbuf[TMPBUFLEN];
        ssize_t length;
-       ssize_t end;
-
-       if (count < 0 || count > PAGE_SIZE)
-               return -EINVAL;
-       if (!(page = (char*)__get_free_page(GFP_KERNEL)))
-               return -ENOMEM;
-       memset(page, 0, PAGE_SIZE);
 
-       length = scnprintf(page, PAGE_SIZE, "%d", selinux_mls_enabled);
-       if (length < 0) {
-               free_page((unsigned long)page);
-               return length;
-       }
-
-       if (*ppos >= length) {
-               free_page((unsigned long)page);
-               return 0;
-       }
-       if (count + *ppos > length)
-               count = length - *ppos;
-       end = count + *ppos;
-       if (copy_to_user(buf, (char *) page + *ppos, count)) {
-               count = -EFAULT;
-               goto out;
-       }
-       *ppos = end;
-out:
-       free_page((unsigned long)page);
-       return count;
+       length = scnprintf(tmpbuf, TMPBUFLEN, "%d", selinux_mls_enabled);
+       return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
 }
 
 static struct file_operations sel_mls_ops = {
@@ -352,10 +273,9 @@ static ssize_t sel_write_context(struct file * file, const char __user * buf,
                /* No partial writes. */
                return -EINVAL;
        }
-       page = (char*)__get_free_page(GFP_KERNEL);
+       page = (char*)get_zeroed_page(GFP_KERNEL);
        if (!page)
                return -ENOMEM;
-       memset(page, 0, PAGE_SIZE);
        length = -EFAULT;
        if (copy_from_user(page, buf, count))
                goto out;
@@ -695,11 +615,10 @@ static ssize_t sel_read_bool(struct file *filep, char __user *buf,
                ret = -EINVAL;
                goto out;
        }
-       if (!(page = (char*)__get_free_page(GFP_KERNEL))) {
+       if (!(page = (char*)get_zeroed_page(GFP_KERNEL))) {
                ret = -ENOMEM;
                goto out;
        }
-       memset(page, 0, PAGE_SIZE);
 
        inode = filep->f_dentry->d_inode;
        cur_enforcing = security_get_bool_value(inode->i_ino - BOOL_INO_OFFSET);
@@ -761,12 +680,11 @@ static ssize_t sel_write_bool(struct file *filep, const char __user *buf,
                /* No partial writes. */
                goto out;
        }
-       page = (char*)__get_free_page(GFP_KERNEL);
+       page = (char*)get_zeroed_page(GFP_KERNEL);
        if (!page) {
                length = -ENOMEM;
                goto out;
        }
-       memset(page, 0, PAGE_SIZE);
 
        if (copy_from_user(page, buf, count))
                goto out;
@@ -820,14 +738,12 @@ static ssize_t sel_commit_bools_write(struct file *filep,
                /* No partial writes. */
                goto out;
        }
-       page = (char*)__get_free_page(GFP_KERNEL);
+       page = (char*)get_zeroed_page(GFP_KERNEL);
        if (!page) {
                length = -ENOMEM;
                goto out;
        }
 
-       memset(page, 0, PAGE_SIZE);
-
        if (copy_from_user(page, buf, count))
                goto out;
 
@@ -913,9 +829,8 @@ static int sel_make_bools(void)
 
        sel_remove_bools(dir);
 
-       if (!(page = (char*)__get_free_page(GFP_KERNEL)))
+       if (!(page = (char*)get_zeroed_page(GFP_KERNEL)))
                return -ENOMEM;
-       memset(page, 0, PAGE_SIZE);
 
        ret = security_get_bools(&num, &names, &values);
        if (ret != 0)