Merge tag 'io_uring-5.5-2020-01-26' of git://git.kernel.dk/linux-block

Pull io_uring fixes from Jens Axboe:
 "Fix for two regressions in this cycle, both reported by the postgresql
  use case.

  One removes the added restriction on who can submit IO, making it
  possible for rings shared across forks to do so. The other fixes an
  issue for the same kind of use case, where one exiting process would
  cancel all IO"

* tag 'io_uring-5.5-2020-01-26' of git://git.kernel.dk/linux-block:
  io_uring: don't cancel all work on process exit
  Revert "io_uring: only allow submit from owning task"

Author: torvalds

fs/io_uring.c

@@ -5044,10 +5044,6 @@ static int io_uring_flush(struct file *file, void *data)
 	struct io_ring_ctx *ctx = file->private_data;
 
 	io_uring_cancel_files(ctx, data);
-	if (fatal_signal_pending(current) || (current->flags & PF_EXITING)) {
-		io_cqring_overflow_flush(ctx, true);
-		io_wq_cancel_all(ctx->io_wq);
-	}
 	return 0;
 }
 
@@ -5161,12 +5157,6 @@ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
 	} else if (to_submit) {
 		struct mm_struct *cur_mm;
 
-		if (current->mm != ctx->sqo_mm ||
-		    current_cred() != ctx->creds) {
-			ret = -EPERM;
-			goto out;
-		}
-
 		to_submit = min(to_submit, ctx->sq_entries);
 		mutex_lock(&ctx->uring_lock);
 		/* already have mm, so io_submit_sqes() won't try to grab it */