diff mbox series

[v4,10/13] mm/madvise: add MADV_COLLAPSE to process_madvise()

Message ID 20220502181714.3483177-11-zokeefe@google.com (mailing list archive)
State New
Headers show
Series mm: userspace hugepage collapse | expand

Commit Message

Zach O'Keefe May 2, 2022, 6:17 p.m. UTC 
Allow MADV_COLLAPSE behavior for process_madvise(2) if caller has
CAP_SYS_ADMIN or is requesting collapse of it's own memory.

Signed-off-by: Zach O'Keefe <zokeefe@google.com>
---
 mm/madvise.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/mm/madvise.c b/mm/madvise.c
index 638517952bd2..08c11217025a 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -1168,13 +1168,15 @@  madvise_behavior_valid(int behavior)
 }
 
 static bool
-process_madvise_behavior_valid(int behavior)
+process_madvise_behavior_valid(int behavior, struct task_struct *task)
 {
 	switch (behavior) {
 	case MADV_COLD:
 	case MADV_PAGEOUT:
 	case MADV_WILLNEED:
 		return true;
+	case MADV_COLLAPSE:
+		return task == current || capable(CAP_SYS_ADMIN);
 	default:
 		return false;
 	}
@@ -1452,7 +1454,7 @@  SYSCALL_DEFINE5(process_madvise, int, pidfd, const struct iovec __user *, vec,
 		goto free_iov;
 	}
 
-	if (!process_madvise_behavior_valid(behavior)) {
+	if (!process_madvise_behavior_valid(behavior, task)) {
 		ret = -EINVAL;
 		goto release_task;
 	}