Restore of huge page shm regions will require that the restarting
process temporarily shmat-attach to regions which are not in the
current ipc namespace. Add an ipc_namespace argument to
do_shmat_pgoff; convert callers to pass current->nsproxy->ipc_ns.
This depends on the patch "support ipc shm regions which are partially
mapped" posted to the containers list on 6 August.
Signed-off-by: Nathan Lynch <ntl@xxxxxxxxx>
---
include/linux/shm.h | 8 +++++---
ipc/shm.c | 15 ++++++++-------
2 files changed, 13 insertions(+), 10 deletions(-)
diff --git a/include/linux/shm.h b/include/linux/shm.h
index 1f6af8c..9ca3196 100644
--- a/include/linux/shm.h
+++ b/include/linux/shm.h
@@ -104,10 +104,12 @@ struct shmid_kernel /* private to the kernel */
#define SHM_NORESERVE 010000 /* don't check for reservations */
#ifdef CONFIG_SYSVIPC
+struct ipc_namespace;
+
long do_shmat(int shmid, char __user *shmaddr, int shmflg, unsigned long *addr);
-long do_shmat_pgoff(int shmid, char __user *shmaddr,
- int shmflg, unsigned long *addr,
- unsigned long shmsize, unsigned long shmpgoff);
+long do_shmat_ns_pgoff(struct ipc_namespace *ns, int shmid,
+ char __user *shmaddr, int shmflg, unsigned long *addr,
+ unsigned long shmsize, unsigned long shmpgoff);
extern int is_file_shm_hugepages(struct file *file);
#else
static inline long do_shmat(int shmid, char __user *shmaddr,
diff --git a/ipc/shm.c b/ipc/shm.c
index 1ba9193..6768fe4 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -321,6 +321,7 @@ static int ipcshm_checkpoint(struct ckpt_ctx *ctx, struct vm_area_struct *vma)
int ipcshm_restore(struct ckpt_ctx *ctx, struct mm_struct *mm,
struct ckpt_hdr_vma *h)
{
+ struct ipc_namespace *ipcns = current->nsproxy->ipc_ns;
struct file *file;
int shmid, shmflg = 0;
unsigned long start;
@@ -348,8 +349,8 @@ int ipcshm_restore(struct ckpt_ctx *ctx, struct mm_struct *mm,
/* do_shmat() below handles partial and offset mapping */
start = (unsigned long) h->vm_start;
size = min(h->ino_size, h->vm_end - h->vm_start);
- ret = do_shmat_pgoff(shmid, (char __user *) start, shmflg,
- &addr, size, h->vm_pgoff << PAGE_SHIFT);
+ ret = do_shmat_ns_pgoff(ipcns, shmid, (char __user *) start, shmflg,
+ &addr, size, h->vm_pgoff << PAGE_SHIFT);
BUG_ON(ret >= 0 && addr != h->vm_start);
return ret;
@@ -880,8 +881,9 @@ out:
* "raddr" thing points to kernel space, and there has to be a wrapper around
* this.
*/
-long do_shmat_pgoff(int shmid, char __user *shmaddr, int shmflg,
- ulong *raddr, ulong shmsize, ulong shmpgoff)
+long do_shmat_ns_pgoff(struct ipc_namespace *ns, int shmid,
+ char __user *shmaddr, int shmflg, ulong *raddr,
+ ulong shmsize, ulong shmpgoff)
{
struct shmid_kernel *shp;
unsigned long addr;
@@ -893,7 +895,6 @@ long do_shmat_pgoff(int shmid, char __user *shmaddr, int shmflg,
unsigned long prot;
int acc_mode;
unsigned long user_addr;
- struct ipc_namespace *ns;
struct shm_file_data *sfd;
struct path path;
fmode_t f_mode;
@@ -937,7 +938,6 @@ long do_shmat_pgoff(int shmid, char __user *shmaddr, int shmflg,
* We cannot rely on the fs check since SYSV IPC does have an
* additional creator id...
*/
- ns = current->nsproxy->ipc_ns;
shp = shm_lock_check(ns, shmid);
if (IS_ERR(shp)) {
err = PTR_ERR(shp);
@@ -1045,7 +1045,8 @@ out_put_dentry:
*/
long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
{
- return do_shmat_pgoff(shmid, shmaddr, shmflg, raddr, 0, 0);
+ return do_shmat_ns_pgoff(current->nsproxy->ipc_ns, shmid, shmaddr,
+ shmflg, raddr, 0, 0);
}
SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
--
1.7.2.2
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