From: Chris Wright <chrisw@osdl.org>
Currently, if a user creates an mqueue and passes an mq_attr, the
info->messages will be created twice (and the extra one is properly freed).
This patch simply delays the allocation so that it only ever happens once.
The relevant mq_attr data is passed to lower levels via the dentry->d_fsdata
fs private data. This also helps isolate the areas we'd need to touch to do
rlimits on mqueues.
---
25-akpm/ipc/mqueue.c | 39 ++++++++++++++-------------------------
1 files changed, 14 insertions(+), 25 deletions(-)
diff -puN ipc/mqueue.c~simplify-mqueue_inode_info-messages-allocation ipc/mqueue.c
--- 25/ipc/mqueue.c~simplify-mqueue_inode_info-messages-allocation 2004-05-04 20:56:06.708480512 -0700
+++ 25-akpm/ipc/mqueue.c 2004-05-04 20:56:06.713479752 -0700
@@ -97,7 +97,8 @@ static inline struct mqueue_inode_info *
return container_of(inode, struct mqueue_inode_info, vfs_inode);
}
-static struct inode *mqueue_get_inode(struct super_block *sb, int mode)
+static struct inode *mqueue_get_inode(struct super_block *sb, int mode,
+ struct mq_attr *attr)
{
struct inode *inode;
@@ -127,7 +128,11 @@ static struct inode *mqueue_get_inode(st
memset(&info->attr, 0, sizeof(info->attr));
info->attr.mq_maxmsg = DFLT_MSGMAX;
info->attr.mq_msgsize = DFLT_MSGSIZEMAX;
- info->messages = kmalloc(DFLT_MSGMAX * sizeof(struct msg_msg *), GFP_KERNEL);
+ if (attr) {
+ info->attr.mq_maxmsg = attr->mq_maxmsg;
+ info->attr.mq_msgsize = attr->mq_msgsize;
+ }
+ info->messages = kmalloc(info->attr.mq_maxmsg * sizeof(struct msg_msg *), GFP_KERNEL);
if (!info->messages) {
make_bad_inode(inode);
iput(inode);
@@ -153,7 +158,7 @@ static int mqueue_fill_super(struct supe
sb->s_magic = MQUEUE_MAGIC;
sb->s_op = &mqueue_super_ops;
- inode = mqueue_get_inode(sb, S_IFDIR | S_ISVTX | S_IRWXUGO);
+ inode = mqueue_get_inode(sb, S_IFDIR | S_ISVTX | S_IRWXUGO, NULL);
if (!inode)
return -ENOMEM;
@@ -226,6 +231,7 @@ static int mqueue_create(struct inode *d
int mode, struct nameidata *nd)
{
struct inode *inode;
+ struct mq_attr *attr = dentry->d_fsdata;
int error;
spin_lock(&mq_lock);
@@ -236,7 +242,7 @@ static int mqueue_create(struct inode *d
queues_count++;
spin_unlock(&mq_lock);
- inode = mqueue_get_inode(dir->i_sb, mode);
+ inode = mqueue_get_inode(dir->i_sb, mode, attr);
if (!inode) {
error = -ENOMEM;
spin_lock(&mq_lock);
@@ -535,9 +541,6 @@ static struct file *do_create(struct den
int oflag, mode_t mode, struct mq_attr __user *u_attr)
{
struct file *filp;
- struct inode *inode;
- struct mqueue_inode_info *info;
- struct msg_msg **msgs = NULL;
struct mq_attr attr;
int ret;
@@ -555,28 +558,14 @@ static struct file *do_create(struct den
attr.mq_msgsize > msgsize_max)
return ERR_PTR(-EINVAL);
}
- msgs = kmalloc(attr.mq_maxmsg * sizeof(*msgs), GFP_KERNEL);
- if (!msgs)
- return ERR_PTR(-ENOMEM);
- } else {
- msgs = NULL;
+ /* store for use during create */
+ dentry->d_fsdata = &attr;
}
ret = vfs_create(dir->d_inode, dentry, mode, NULL);
- if (ret) {
- kfree(msgs);
+ dentry->d_fsdata = NULL;
+ if (ret)
return ERR_PTR(ret);
- }
-
- inode = dentry->d_inode;
- info = MQUEUE_I(inode);
-
- if (msgs) {
- info->attr.mq_maxmsg = attr.mq_maxmsg;
- info->attr.mq_msgsize = attr.mq_msgsize;
- kfree(info->messages);
- info->messages = msgs;
- }
filp = dentry_open(dentry, mqueue_mnt, oflag);
if (!IS_ERR(filp))
_