Merge tag 'for-5.7/io_uring-2020-03-29' of git://git.kernel.dk/linux-block

Pull io_uring updates from Jens Axboe:
 "Here are the io_uring changes for this merge window. Light on new
  features this time around (just splice + buffer selection), lots of
  cleanups, fixes, and improvements to existing support. In particular,
  this contains:

   - Cleanup fixed file update handling for stack fallback (Hillf)

   - Re-work of how pollable async IO is handled, we no longer require
     thread offload to handle that. Instead we rely using poll to drive
     this, with task_work execution.

   - In conjunction with the above, allow expendable buffer selection,
     so that poll+recv (for example) no longer has to be a split
     operation.

   - Make sure we honor RLIMIT_FSIZE for buffered writes

   - Add support for splice (Pavel)

   - Linked work inheritance fixes and optimizations (Pavel)

   - Async work fixes and cleanups (Pavel)

   - Improve io-wq locking (Pavel)

   - Hashed link write improvements (Pavel)

   - SETUP_IOPOLL|SETUP_SQPOLL improvements (Xiaoguang)"

* tag 'for-5.7/io_uring-2020-03-29' of git://git.kernel.dk/linux-block: (54 commits)
  io_uring: cleanup io_alloc_async_ctx()
  io_uring: fix missing 'return' in comment
  io-wq: handle hashed writes in chains
  io-uring: drop 'free_pfile' in struct io_file_put
  io-uring: drop completion when removing file
  io_uring: Fix ->data corruption on re-enqueue
  io-wq: close cancel gap for hashed linked work
  io_uring: make spdxcheck.py happy
  io_uring: honor original task RLIMIT_FSIZE
  io-wq: hash dependent work
  io-wq: split hashing and enqueueing
  io-wq: don't resched if there is no work
  io-wq: remove duplicated cancel code
  io_uring: fix truncated async read/readv and write/writev retry
  io_uring: dual license io_uring.h uapi header
  io_uring: io_uring_enter(2) don't poll while SETUP_IOPOLL|SETUP_SQPOLL enabled
  io_uring: Fix unused function warnings
  io_uring: add end-of-bits marker and build time verify it
  io_uring: provide means of removing buffers
  io_uring: add IOSQE_BUFFER_SELECT support for IORING_OP_RECVMSG
  ...

1 files changed, 21 insertions, 4 deletions

diff --git a/net/socket.c b/net/socket.c
index 2eecf1517f76..2dd739fba866 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -2228,10 +2228,10 @@ struct used_address {
 	unsigned int name_len;
 };
 
-static int copy_msghdr_from_user(struct msghdr *kmsg,
-				 struct user_msghdr __user *umsg,
-				 struct sockaddr __user **save_addr,
-				 struct iovec **iov)
+int __copy_msghdr_from_user(struct msghdr *kmsg,
+			    struct user_msghdr __user *umsg,
+			    struct sockaddr __user **save_addr,
+			    struct iovec __user **uiov, size_t *nsegs)
 {
 	struct user_msghdr msg;
 	ssize_t err;
@@ -2273,6 +2273,23 @@ static int copy_msghdr_from_user(struct msghdr *kmsg,
 		return -EMSGSIZE;
 
 	kmsg->msg_iocb = NULL;
+	*uiov = msg.msg_iov;
+	*nsegs = msg.msg_iovlen;
+	return 0;
+}
+
+static int copy_msghdr_from_user(struct msghdr *kmsg,
+				 struct user_msghdr __user *umsg,
+				 struct sockaddr __user **save_addr,
+				 struct iovec **iov)
+{
+	struct user_msghdr msg;
+	ssize_t err;
+
+	err = __copy_msghdr_from_user(kmsg, umsg, save_addr, &msg.msg_iov,
+					&msg.msg_iovlen);
+	if (err)
+		return err;
 
 	err = import_iovec(save_addr ? READ : WRITE,
 			    msg.msg_iov, msg.msg_iovlen,