[13/16] mm: bool user_shm_lock(loff_t size, struct ucounts *)

Commit Message

Hugh Dickins July 30, 2021, 8:03 a.m. UTC

user_shm_lock()'s size_t size was big enough for SysV SHM locking, but
not quite big enough for O_LARGEFILE on 32-bit: change to loff_t size.
And while changing the prototype, let's use bool rather than int here.

Signed-off-by: Hugh Dickins <[e-mail]>
---
 include/linux/mm.h |  4 ++--
 mm/mlock.c         | 14 +++++++-------
 2 files changed, 9 insertions(+), 9 deletions(-)

Patch

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 7ca22e6e694a..f1be2221512b 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1713,8 +1713,8 @@  extern bool can_do_mlock(void);
 #else
 static inline bool can_do_mlock(void) { return false; }
 #endif
-extern int user_shm_lock(size_t, struct ucounts *);
-extern void user_shm_unlock(size_t, struct ucounts *);
+extern bool user_shm_lock(loff_t size, struct ucounts *ucounts);
+extern void user_shm_unlock(loff_t size, struct ucounts *ucounts);
 
 /*
  * Parameter block passed down to zap_pte_range in exceptional cases.
diff --git a/mm/mlock.c b/mm/mlock.c
index 16d2ee160d43..7df88fce0fc9 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -813,21 +813,21 @@  SYSCALL_DEFINE0(munlockall)
 }
 
 /*
- * Objects with different lifetime than processes (SHM_LOCK and SHM_HUGETLB
- * shm segments) get accounted against the user_struct instead.
+ * Objects with different lifetime than processes (SHM_LOCK and SHM_HUGETLB shm
+ * segments and F_MEM_LOCK tmpfs) get accounted to the user_namespace instead.
  */
 static DEFINE_SPINLOCK(shmlock_user_lock);
 
-int user_shm_lock(size_t size, struct ucounts *ucounts)
+bool user_shm_lock(loff_t size, struct ucounts *ucounts)
 {
 	unsigned long lock_limit, locked;
 	long memlock;
-	int allowed = 0;
+	bool allowed = false;
 
 	locked = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
 	lock_limit = rlimit(RLIMIT_MEMLOCK);
 	if (lock_limit == RLIM_INFINITY)
-		allowed = 1;
+		allowed = true;
 	lock_limit >>= PAGE_SHIFT;
 	spin_lock(&shmlock_user_lock);
 	memlock = inc_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked);
@@ -840,13 +840,13 @@  int user_shm_lock(size_t size, struct ucounts *ucounts)
 		dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked);
 		goto out;
 	}
-	allowed = 1;
+	allowed = true;
 out:
 	spin_unlock(&shmlock_user_lock);
 	return allowed;
 }
 
-void user_shm_unlock(size_t size, struct ucounts *ucounts)
+void user_shm_unlock(loff_t size, struct ucounts *ucounts)
 {
 	spin_lock(&shmlock_user_lock);
 	dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, (size + PAGE_SIZE - 1) >> PAGE_SHIFT);