[PATCH 5.15 220/277] io_uring: implement compat handling for IORING_REGISTER_IOWQ_AFF

[Greg Kroah-Hartman]

From: Eugene Syromiatnikov <esyr@xxxxxxxxxx>

commit 0f5e4b83b37a96e3643951588ed7176b9b187c0a upstream.

Similarly to the way it is done im mbind syscall.

Cc: stable@xxxxxxxxxxxxxxx # 5.14
Fixes: fe76421d1da1dcdb ("io_uring: allow user configurable IO thread CPU affinity")
Signed-off-by: Eugene Syromiatnikov <esyr@xxxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 fs/io_uring.c |   10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -10683,7 +10683,15 @@ static int io_register_iowq_aff(struct i
 	if (len > cpumask_size())
 		len = cpumask_size();
 
-	if (copy_from_user(new_mask, arg, len)) {
+	if (in_compat_syscall()) {
+		ret = compat_get_bitmap(cpumask_bits(new_mask),
+					(const compat_ulong_t __user *)arg,
+					len * 8 /* CHAR_BIT */);
+	} else {
+		ret = copy_from_user(new_mask, arg, len);
+	}
+
+	if (ret) {
 		free_cpumask_var(new_mask);
 		return -EFAULT;
 	}