[PATCH] hugetlb: report shared memory attachment counts

From Rohit Seth

Attached is a patch that passes the correct information back to user
land for number of attachments to shared memory segment.  I could have
done few more changes in a way nattach is getting set for regular cases
now, but just want to limit it at this point.

ipc/shm.c

@@ -465,7 +465,10 @@ asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds *buf)
 		tbuf.shm_ctime	= shp->shm_ctim;
 		tbuf.shm_cpid	= shp->shm_cprid;
 		tbuf.shm_lpid	= shp->shm_lprid;
-		tbuf.shm_nattch	= shp->shm_nattch;
+		if (!is_file_hugepages(shp->shm_file))
+			tbuf.shm_nattch	= shp->shm_nattch;
+		else
+			tbuf.shm_nattch = file_count(shp->shm_file) - 1;
 		shm_unlock(shp);
 		if(copy_shmid_to_user (buf, &tbuf, version))
 			err = -EFAULT;
@@ -746,7 +749,7 @@ static int sysvipc_shm_read_proc(char *buffer, char **start, off_t offset, int l
 				shp->shm_segsz,
 				shp->shm_cprid,
 				shp->shm_lprid,
-				shp->shm_nattch,
+				is_file_hugepages(shp->shm_file) ? (file_count(shp->shm_file) - 1) : shp->shm_nattch,
 				shp->shm_perm.uid,
 				shp->shm_perm.gid,
 				shp->shm_perm.cuid,