[RFC][PATCH 5/6] sysvshm: containerize

From: Dave Hansen
Date: Mon Mar 06 2006 - 18:52:26 EST


Same thing as sems and msgs.

Take all of the global sysv shm context and put it inside of
a special structure. This allows future work to give different
containers completely different views into the sysv space.

Signed-off-by: Dave Hansen <haveblue@xxxxxxxxxx>
---

work-dave/ipc/shm.c | 197 +++++++++++++++++++++++++++------------------------
work-dave/ipc/util.c | 3
work-dave/ipc/util.h | 9 ++
3 files changed, 118 insertions(+), 91 deletions(-)

diff -puN include/linux/sched.h~sysvshm-container include/linux/sched.h
diff -puN ipc/shm.c~sysvshm-container ipc/shm.c
--- work/ipc/shm.c~sysvshm-container 2006-03-06 15:41:59.000000000 -0800
+++ work-dave/ipc/shm.c 2006-03-06 15:41:59.000000000 -0800
@@ -38,15 +38,17 @@
static struct file_operations shm_file_operations;
static struct vm_operations_struct shm_vm_ops;

-static struct ipc_ids shm_ids;
+#define shm_lock(context, id) \
+ ((struct shmid_kernel*)ipc_lock(&context->ids,id))
+#define shm_unlock(context, shp) \
+ ipc_unlock(&(shp)->shm_perm)
+#define shm_get(context, id)\
+ ((struct shmid_kernel*)ipc_get(&context->ids,id))
+#define shm_buildid(context, id, seq) \
+ ipc_buildid(&context->ids, id, seq)

-#define shm_lock(id) ((struct shmid_kernel*)ipc_lock(&shm_ids,id))
-#define shm_unlock(shp) ipc_unlock(&(shp)->shm_perm)
-#define shm_get(id) ((struct shmid_kernel*)ipc_get(&shm_ids,id))
-#define shm_buildid(id, seq) \
- ipc_buildid(&shm_ids, id, seq)
-
-static int newseg (key_t key, int shmflg, size_t size);
+static int newseg (struct ipc_shm_context *context,
+ key_t key, int shmflg, size_t size);
static void shm_open (struct vm_area_struct *shmd);
static void shm_close (struct vm_area_struct *shmd);
#ifdef CONFIG_PROC_FS
@@ -57,51 +59,53 @@ size_t shm_ctlmax = SHMMAX;
size_t shm_ctlall = SHMALL;
int shm_ctlmni = SHMMNI;

-static int shm_tot; /* total number of shared memory pages */
-
-void __init shm_init (void)
+void __init shm_init (struct ipc_shm_context *context)
{
- ipc_init_ids(&shm_ids, 1);
+ ipc_init_ids(&context->ids, 1);
ipc_init_proc_interface("sysvipc/shm",
" key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime\n",
- &shm_ids,
+ &context->ids,
sysvipc_shm_proc_show);
}

-static inline int shm_checkid(struct shmid_kernel *s, int id)
+static inline int shm_checkid(struct ipc_shm_context *context,
+ struct shmid_kernel *s, int id)
{
- if (ipc_checkid(&shm_ids,&s->shm_perm,id))
+ if (ipc_checkid(&context->ids,&s->shm_perm,id))
return -EIDRM;
return 0;
}

-static inline struct shmid_kernel *shm_rmid(int id)
+static inline
+struct shmid_kernel *shm_rmid(struct ipc_shm_context *context, int id)
{
- return (struct shmid_kernel *)ipc_rmid(&shm_ids,id);
+ return (struct shmid_kernel *)ipc_rmid(&context->ids,id);
}

-static inline int shm_addid(struct shmid_kernel *shp)
+static inline
+int shm_addid(struct ipc_shm_context *context, struct shmid_kernel *shp)
{
- return ipc_addid(&shm_ids, &shp->shm_perm, shm_ctlmni);
+ return ipc_addid(&context->ids, &shp->shm_perm, shm_ctlmni);
}



-static inline void shm_inc (int id) {
+static inline void shm_inc (struct ipc_shm_context *context, int id) {
struct shmid_kernel *shp;

- if(!(shp = shm_lock(id)))
+ if(!(shp = shm_lock(context, id)))
BUG();
shp->shm_atim = get_seconds();
shp->shm_lprid = current->tgid;
shp->shm_nattch++;
- shm_unlock(shp);
+ shm_unlock(context, shp);
}

/* This is called by fork, once for every shm attach. */
static void shm_open (struct vm_area_struct *shmd)
{
- shm_inc (shmd->vm_file->f_dentry->d_inode->i_ino);
+ struct ipc_shm_context *context = shmd->vm_private_data;
+ shm_inc (context, shmd->vm_file->f_dentry->d_inode->i_ino);
}

/*
@@ -109,14 +113,15 @@ static void shm_open (struct vm_area_str
*
* @shp: struct to free
*
- * It has to be called with shp and shm_ids.sem locked,
+ * It has to be called with shp and context->ids.sem locked,
* but returns with shp unlocked and freed.
*/
-static void shm_destroy (struct shmid_kernel *shp)
+static void shm_destroy (struct ipc_shm_context *context,
+ struct shmid_kernel *shp)
{
- shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
- shm_rmid (shp->id);
- shm_unlock(shp);
+ context->tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ shm_rmid (context, shp->id);
+ shm_unlock(context, shp);
if (!is_file_hugepages(shp->shm_file))
shmem_lock(shp->shm_file, 0, shp->mlock_user);
else
@@ -138,30 +143,39 @@ static void shm_close (struct vm_area_st
struct file * file = shmd->vm_file;
int id = file->f_dentry->d_inode->i_ino;
struct shmid_kernel *shp;
+ struct ipc_shm_context *context = shmd->vm_private_data;

- down (&shm_ids.sem);
+ down (&context->ids.sem);
/* remove from the list of attaches of the shm segment */
- if(!(shp = shm_lock(id)))
+ if(!(shp = shm_lock(context, id)))
BUG();
shp->shm_lprid = current->tgid;
shp->shm_dtim = get_seconds();
shp->shm_nattch--;
if(shp->shm_nattch == 0 &&
shp->shm_perm.mode & SHM_DEST)
- shm_destroy (shp);
+ shm_destroy (context, shp);
else
- shm_unlock(shp);
- up (&shm_ids.sem);
+ shm_unlock(context, shp);
+ up (&context->ids.sem);
}

static int shm_mmap(struct file * file, struct vm_area_struct * vma)
{
int ret;
+ struct ipc_shm_context *context = current->ipc_shm_context;

ret = shmem_mmap(file, vma);
if (ret == 0) {
vma->vm_ops = &shm_vm_ops;
- shm_inc(file->f_dentry->d_inode->i_ino);
+ /*
+ * This implies that the shm context can not change
+ * while a task is running because this mmap's
+ * context would change underneath it.
+ * -- You many only change shm context at exec()
+ */
+ vma->vm_private_data = context;
+ shm_inc(context, file->f_dentry->d_inode->i_ino);
}

return ret;
@@ -184,7 +198,8 @@ static struct vm_operations_struct shm_v
#endif
};

-static int newseg (key_t key, int shmflg, size_t size)
+static int newseg (struct ipc_shm_context *context,
+ key_t key, int shmflg, size_t size)
{
int error;
struct shmid_kernel *shp;
@@ -196,7 +211,7 @@ static int newseg (key_t key, int shmflg
if (size < SHMMIN || size > shm_ctlmax)
return -EINVAL;

- if (shm_tot + numpages >= shm_ctlall)
+ if (context->tot + numpages >= shm_ctlall)
return -ENOSPC;

shp = ipc_rcu_alloc(sizeof(*shp));
@@ -235,7 +250,7 @@ static int newseg (key_t key, int shmflg
goto no_file;

error = -ENOSPC;
- id = shm_addid(shp);
+ id = shm_addid(context, shp);
if(id == -1)
goto no_id;

@@ -245,7 +260,7 @@ static int newseg (key_t key, int shmflg
shp->shm_ctim = get_seconds();
shp->shm_segsz = size;
shp->shm_nattch = 0;
- shp->id = shm_buildid(id,shp->shm_perm.seq);
+ shp->id = shm_buildid(context, id,shp->shm_perm.seq);
shp->shm_file = file;
file->f_dentry->d_inode->i_ino = shp->id;

@@ -253,8 +268,8 @@ static int newseg (key_t key, int shmflg
if (!(shmflg & SHM_HUGETLB))
file->f_op = &shm_file_operations;

- shm_tot += numpages;
- shm_unlock(shp);
+ context->tot += numpages;
+ shm_unlock(context, shp);
return shp->id;

no_id:
@@ -269,19 +284,20 @@ asmlinkage long sys_shmget (key_t key, s
{
struct shmid_kernel *shp;
int err, id = 0;
+ struct ipc_shm_context *context = current->ipc_shm_context;

- down(&shm_ids.sem);
+ down(&context->ids.sem);
if (key == IPC_PRIVATE) {
- err = newseg(key, shmflg, size);
- } else if ((id = ipc_findkey(&shm_ids, key)) == -1) {
+ err = newseg(context, key, shmflg, size);
+ } else if ((id = ipc_findkey(&context->ids, key)) == -1) {
if (!(shmflg & IPC_CREAT))
err = -ENOENT;
else
- err = newseg(key, shmflg, size);
+ err = newseg(context, key, shmflg, size);
} else if ((shmflg & IPC_CREAT) && (shmflg & IPC_EXCL)) {
err = -EEXIST;
} else {
- shp = shm_lock(id);
+ shp = shm_lock(context, id);
if(shp==NULL)
BUG();
if (shp->shm_segsz < size)
@@ -289,14 +305,14 @@ asmlinkage long sys_shmget (key_t key, s
else if (ipcperms(&shp->shm_perm, shmflg))
err = -EACCES;
else {
- int shmid = shm_buildid(id, shp->shm_perm.seq);
+ int shmid = shm_buildid(context, id, shp->shm_perm.seq);
err = security_shm_associate(shp, shmflg);
if (!err)
err = shmid;
}
- shm_unlock(shp);
+ shm_unlock(context, shp);
}
- up(&shm_ids.sem);
+ up(&context->ids.sem);

return err;
}
@@ -392,18 +408,19 @@ static inline unsigned long copy_shminfo
}
}

-static void shm_get_stat(unsigned long *rss, unsigned long *swp)
+static void shm_get_stat(struct ipc_shm_context *context,
+ unsigned long *rss, unsigned long *swp)
{
int i;

*rss = 0;
*swp = 0;

- for (i = 0; i <= shm_ids.max_id; i++) {
+ for (i = 0; i <= context->ids.max_id; i++) {
struct shmid_kernel *shp;
struct inode *inode;

- shp = shm_get(i);
+ shp = shm_get(context, i);
if(!shp)
continue;

@@ -427,6 +444,7 @@ asmlinkage long sys_shmctl (int shmid, i
struct shm_setbuf setbuf;
struct shmid_kernel *shp;
int err, version;
+ struct ipc_shm_context *context = current->ipc_shm_context;

if (cmd < 0 || shmid < 0) {
err = -EINVAL;
@@ -453,7 +471,7 @@ asmlinkage long sys_shmctl (int shmid, i
if(copy_shminfo_to_user (buf, &shminfo, version))
return -EFAULT;
/* reading a integer is always atomic */
- err= shm_ids.max_id;
+ err= context->ids.max_id;
if(err<0)
err = 0;
goto out;
@@ -467,14 +485,14 @@ asmlinkage long sys_shmctl (int shmid, i
return err;

memset(&shm_info,0,sizeof(shm_info));
- down(&shm_ids.sem);
- shm_info.used_ids = shm_ids.in_use;
- shm_get_stat (&shm_info.shm_rss, &shm_info.shm_swp);
- shm_info.shm_tot = shm_tot;
+ down(&context->ids.sem);
+ shm_info.used_ids = context->ids.in_use;
+ shm_get_stat (context, &shm_info.shm_rss, &shm_info.shm_swp);
+ shm_info.shm_tot = context->tot;
shm_info.swap_attempts = 0;
shm_info.swap_successes = 0;
- err = shm_ids.max_id;
- up(&shm_ids.sem);
+ err = context->ids.max_id;
+ up(&context->ids.sem);
if(copy_to_user (buf, &shm_info, sizeof(shm_info))) {
err = -EFAULT;
goto out;
@@ -489,17 +507,17 @@ asmlinkage long sys_shmctl (int shmid, i
struct shmid64_ds tbuf;
int result;
memset(&tbuf, 0, sizeof(tbuf));
- shp = shm_lock(shmid);
+ shp = shm_lock(context, shmid);
if(shp==NULL) {
err = -EINVAL;
goto out;
} else if(cmd==SHM_STAT) {
err = -EINVAL;
- if (shmid > shm_ids.max_id)
+ if (shmid > context->ids.max_id)
goto out_unlock;
- result = shm_buildid(shmid, shp->shm_perm.seq);
+ result = shm_buildid(context, shmid, shp->shm_perm.seq);
} else {
- err = shm_checkid(shp,shmid);
+ err = shm_checkid(context,shp,shmid);
if(err)
goto out_unlock;
result = 0;
@@ -521,7 +539,7 @@ asmlinkage long sys_shmctl (int shmid, i
tbuf.shm_nattch = shp->shm_nattch;
else
tbuf.shm_nattch = file_count(shp->shm_file) - 1;
- shm_unlock(shp);
+ shm_unlock(context, shp);
if(copy_shmid_to_user (buf, &tbuf, version))
err = -EFAULT;
else
@@ -531,12 +549,12 @@ asmlinkage long sys_shmctl (int shmid, i
case SHM_LOCK:
case SHM_UNLOCK:
{
- shp = shm_lock(shmid);
+ shp = shm_lock(context, shmid);
if(shp==NULL) {
err = -EINVAL;
goto out;
}
- err = shm_checkid(shp,shmid);
+ err = shm_checkid(context,shp,shmid);
if(err)
goto out_unlock;

@@ -568,7 +586,7 @@ asmlinkage long sys_shmctl (int shmid, i
shp->shm_perm.mode &= ~SHM_LOCKED;
shp->mlock_user = NULL;
}
- shm_unlock(shp);
+ shm_unlock(context, shp);
goto out;
}
case IPC_RMID:
@@ -583,12 +601,12 @@ asmlinkage long sys_shmctl (int shmid, i
* Instead we set a destroyed flag, and then blow
* the name away when the usage hits zero.
*/
- down(&shm_ids.sem);
- shp = shm_lock(shmid);
+ down(&context->ids.sem);
+ shp = shm_lock(context, shmid);
err = -EINVAL;
if (shp == NULL)
goto out_up;
- err = shm_checkid(shp, shmid);
+ err = shm_checkid(context, shp, shmid);
if(err)
goto out_unlock_up;

@@ -607,10 +625,10 @@ asmlinkage long sys_shmctl (int shmid, i
shp->shm_perm.mode |= SHM_DEST;
/* Do not find it any more */
shp->shm_perm.key = IPC_PRIVATE;
- shm_unlock(shp);
+ shm_unlock(context, shp);
} else
- shm_destroy (shp);
- up(&shm_ids.sem);
+ shm_destroy (context, shp);
+ up(&context->ids.sem);
goto out;
}

@@ -622,12 +640,12 @@ asmlinkage long sys_shmctl (int shmid, i
}
if ((err = audit_ipc_perms(0, setbuf.uid, setbuf.gid, setbuf.mode)))
return err;
- down(&shm_ids.sem);
- shp = shm_lock(shmid);
+ down(&context->ids.sem);
+ shp = shm_lock(context, shmid);
err=-EINVAL;
if(shp==NULL)
goto out_up;
- err = shm_checkid(shp,shmid);
+ err = shm_checkid(context,shp,shmid);
if(err)
goto out_unlock_up;
err=-EPERM;
@@ -656,12 +674,12 @@ asmlinkage long sys_shmctl (int shmid, i

err = 0;
out_unlock_up:
- shm_unlock(shp);
+ shm_unlock(context, shp);
out_up:
- up(&shm_ids.sem);
+ up(&context->ids.sem);
goto out;
out_unlock:
- shm_unlock(shp);
+ shm_unlock(context, shp);
out:
return err;
}
@@ -675,6 +693,7 @@ out:
*/
long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
{
+ struct ipc_shm_context *context = current->ipc_shm_context;
struct shmid_kernel *shp;
unsigned long addr;
unsigned long size;
@@ -725,32 +744,32 @@ long do_shmat(int shmid, char __user *sh
* We cannot rely on the fs check since SYSV IPC does have an
* additional creator id...
*/
- shp = shm_lock(shmid);
+ shp = shm_lock(context, shmid);
if(shp == NULL) {
err = -EINVAL;
goto out;
}
- err = shm_checkid(shp,shmid);
+ err = shm_checkid(context,shp,shmid);
if (err) {
- shm_unlock(shp);
+ shm_unlock(context, shp);
goto out;
}
if (ipcperms(&shp->shm_perm, acc_mode)) {
- shm_unlock(shp);
+ shm_unlock(context, shp);
err = -EACCES;
goto out;
}

err = security_shm_shmat(shp, shmaddr, shmflg);
if (err) {
- shm_unlock(shp);
+ shm_unlock(context, shp);
return err;
}

file = shp->shm_file;
size = i_size_read(file->f_dentry->d_inode);
shp->shm_nattch++;
- shm_unlock(shp);
+ shm_unlock(context, shp);

down_write(&current->mm->mmap_sem);
if (addr && !(shmflg & SHM_REMAP)) {
@@ -771,16 +790,16 @@ long do_shmat(int shmid, char __user *sh
invalid:
up_write(&current->mm->mmap_sem);

- down (&shm_ids.sem);
- if(!(shp = shm_lock(shmid)))
+ down (&context->ids.sem);
+ if(!(shp = shm_lock(context, shmid)))
BUG();
shp->shm_nattch--;
if(shp->shm_nattch == 0 &&
shp->shm_perm.mode & SHM_DEST)
- shm_destroy (shp);
+ shm_destroy (context, shp);
else
- shm_unlock(shp);
- up (&shm_ids.sem);
+ shm_unlock(context, shp);
+ up (&context->ids.sem);

*raddr = (unsigned long) user_addr;
err = 0;
diff -puN ipc/util.c~sysvshm-container ipc/util.c
--- work/ipc/util.c~sysvshm-container 2006-03-06 15:41:59.000000000 -0800
+++ work-dave/ipc/util.c 2006-03-06 15:41:59.000000000 -0800
@@ -46,6 +46,7 @@ struct ipc_proc_iface {
* memory are initialised
*/

+struct ipc_shm_context *ipc_shm_context;
static int __init ipc_init(void)
{
init_task.ipc_context = kzalloc(sizeof(*ipc_context), GFP_KERNEL);
@@ -54,7 +55,7 @@ static int __init ipc_init(void)

sem_init(&init_task.ipc_context->sem);
msg_init(&init_task.ipc_context->msg);
- shm_init();
+ shm_init(&init_task.ipc_context->shm);
return 0;
}
__initcall(ipc_init);
diff -puN ipc/util.h~sysvshm-container ipc/util.h
--- work/ipc/util.h~sysvshm-container 2006-03-06 15:41:59.000000000 -0800
+++ work-dave/ipc/util.h 2006-03-06 15:41:59.000000000 -0800
@@ -44,14 +44,21 @@ struct ipc_sem_context {
int nr_used;
};

+struct ipc_shm_context {
+ struct ipc_ids ids;
+
+ int tot; /* total number of shared memory pages */
+};
+
struct ipc_context {
struct ipc_msg_context msg;
struct ipc_sem_context sem;
+ struct ipc_shm_context shm;
};

void sem_init (struct ipc_sem_context *context);
void msg_init (struct ipc_msg_context *context);
-void shm_init (void);
+void shm_init (struct ipc_shm_context *context);

struct seq_file;
void __init ipc_init_ids(struct ipc_ids* ids, int size);
_
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/