mm,hugetlb: remove mlock ulimit for SHM_HUGETLB

Commit 21a3c27 ("mm, hugetlb: add thread name and pid to
SHM_HUGETLB mlock rlimit warning") marked this as deprecated in 2012,
but it is not deleted yet.

Mike says he still sees that message in log files on occasion, so maybe we
should preserve this warning.

Also remove hugetlbfs related user_shm_unlock in ipc/shm.c and remove the
user_shm_unlock after out.

Link: https://lkml.kernel.org/r/20211103105857.25041-1-zhangyiru3@huawei.com
Signed-off-by: zhangyiru <zhangyiru3@huawei.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Liu Zixian <liuzixian4@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: wuxu.wu <wuxu.wu@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/hugetlbfs/inode.c

@@ -1446,8 +1446,8 @@ static int get_hstate_idx(int page_size_log)
  * otherwise hugetlb_reserve_pages reserves one less hugepages than intended.
  */
 struct file *hugetlb_file_setup(const char *name, size_t size,
-				vm_flags_t acctflag, struct ucounts **ucounts,
-				int creat_flags, int page_size_log)
+				vm_flags_t acctflag, int creat_flags,
+				int page_size_log)
 {
 	struct inode *inode;
 	struct vfsmount *mnt;
@@ -1458,22 +1458,19 @@ struct file *hugetlb_file_setup(const char *name, size_t size,
 	if (hstate_idx < 0)
 		return ERR_PTR(-ENODEV);
 
-	*ucounts = NULL;
 	mnt = hugetlbfs_vfsmount[hstate_idx];
 	if (!mnt)
 		return ERR_PTR(-ENOENT);
 
 	if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
-		*ucounts = current_ucounts();
-		if (user_shm_lock(size, *ucounts)) {
-			task_lock(current);
-			pr_warn_once("%s (%d): Using mlock ulimits for SHM_HUGETLB is deprecated\n",
+		struct ucounts *ucounts = current_ucounts();
+
+		if (user_shm_lock(size, ucounts)) {
+			pr_warn_once("%s (%d): Using mlock ulimits for SHM_HUGETLB is obsolete\n",
 				current->comm, current->pid);
-			task_unlock(current);
-		} else {
-			*ucounts = NULL;
-			return ERR_PTR(-EPERM);
+			user_shm_unlock(size, ucounts);
 		}
+		return ERR_PTR(-EPERM);
 	}
 
 	file = ERR_PTR(-ENOSPC);
@@ -1498,10 +1495,6 @@ struct file *hugetlb_file_setup(const char *name, size_t size,
 
 	iput(inode);
 out:
-	if (*ucounts) {
-		user_shm_unlock(size, *ucounts);
-		*ucounts = NULL;
-	}
 	return file;
 }
 

include/linux/hugetlb.h

@@ -477,8 +477,7 @@ static inline struct hugetlbfs_inode_info *HUGETLBFS_I(struct inode *inode)
 extern const struct file_operations hugetlbfs_file_operations;
 extern const struct vm_operations_struct hugetlb_vm_ops;
 struct file *hugetlb_file_setup(const char *name, size_t size, vm_flags_t acct,
-				struct ucounts **ucounts, int creat_flags,
-				int page_size_log);
+				int creat_flags, int page_size_log);
 
 static inline bool is_file_hugepages(struct file *file)
 {
@@ -497,8 +496,7 @@ static inline struct hstate *hstate_inode(struct inode *i)
 #define is_file_hugepages(file)			false
 static inline struct file *
 hugetlb_file_setup(const char *name, size_t size, vm_flags_t acctflag,
-		struct ucounts **ucounts, int creat_flags,
-		int page_size_log)
+		int creat_flags, int page_size_log)
 {
 	return ERR_PTR(-ENOSYS);
 }

ipc/shm.c

@@ -287,9 +287,6 @@ static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
 	shm_unlock(shp);
 	if (!is_file_hugepages(shm_file))
 		shmem_lock(shm_file, 0, shp->mlock_ucounts);
-	else if (shp->mlock_ucounts)
-		user_shm_unlock(i_size_read(file_inode(shm_file)),
-				shp->mlock_ucounts);
 	fput(shm_file);
 	ipc_update_pid(&shp->shm_cprid, NULL);
 	ipc_update_pid(&shp->shm_lprid, NULL);
@@ -650,8 +647,7 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
 		if (shmflg & SHM_NORESERVE)
 			acctflag = VM_NORESERVE;
 		file = hugetlb_file_setup(name, hugesize, acctflag,
-				  &shp->mlock_ucounts, HUGETLB_SHMFS_INODE,
-				(shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
+				HUGETLB_SHMFS_INODE, (shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
 	} else {
 		/*
 		 * Do not allow no accounting for OVERCOMMIT_NEVER, even
@@ -698,8 +694,6 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
 no_id:
 	ipc_update_pid(&shp->shm_cprid, NULL);
 	ipc_update_pid(&shp->shm_lprid, NULL);
-	if (is_file_hugepages(file) && shp->mlock_ucounts)
-		user_shm_unlock(size, shp->mlock_ucounts);
 	fput(file);
 	ipc_rcu_putref(&shp->shm_perm, shm_rcu_free);
 	return error;

mm/memfd.c

@@ -297,9 +297,7 @@ SYSCALL_DEFINE2(memfd_create,
 	}
 
 	if (flags & MFD_HUGETLB) {
-		struct ucounts *ucounts = NULL;
-
-		file = hugetlb_file_setup(name, 0, VM_NORESERVE, &ucounts,
+		file = hugetlb_file_setup(name, 0, VM_NORESERVE,
 					HUGETLB_ANONHUGE_INODE,
 					(flags >> MFD_HUGE_SHIFT) &
 					MFD_HUGE_MASK);

mm/mmap.c

@@ -1599,7 +1599,6 @@ unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len,
 			goto out_fput;
 		}
 	} else if (flags & MAP_HUGETLB) {
-		struct ucounts *ucounts = NULL;
 		struct hstate *hs;
 
 		hs = hstate_sizelog((flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK);
@@ -1615,7 +1614,7 @@ unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len,
 		 */
 		file = hugetlb_file_setup(HUGETLB_ANON_FILE, len,
 				VM_NORESERVE,
-				&ucounts, HUGETLB_ANONHUGE_INODE,
+				HUGETLB_ANONHUGE_INODE,
 				(flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK);
 		if (IS_ERR(file))
 			return PTR_ERR(file);