No functional changes in this patch, needed to provide io_uring support
for shutdown(2).

Cc: netdev@vger.kernel.org
Cc: David S. Miller <davem@davemloft.net>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

The header file linux/uio.h includes crypto/hash.h which pulls in
most of the Crypto API.  Since linux/uio.h is used throughout the
kernel this means that every tiny bit of change to the Crypto API
causes the entire kernel to get rebuilt.

This patch fixes this by moving it into lib/iov_iter.c instead
where it is actually used.

This patch also fixes the ifdef to use CRYPTO_HASH instead of just
CRYPTO which does not guarantee the existence of ahash.

Unfortunately a number of drivers were relying on linux/uio.h to
provide access to linux/slab.h.  This patch adds inclusions of
linux/slab.h as detected by build failures.

Also skbuff.h was relying on this to provide a declaration for
ahash_request.  This patch adds a forward declaration instead.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

The msg_control field in struct msghdr can either contain a user
pointer when used with the recvmsg system call, or a kernel pointer
when used with sendmsg.  To complicate things further kernel_recvmsg
can stuff a kernel pointer in and then use set_fs to make the uaccess
helpers accept it.

Replace it with a union of a kernel pointer msg_control field, and
a user pointer msg_control_user one, and allow kernel_recvmsg operate
on a proper kernel pointer using a bitfield to override the normal
choice of a user pointer for recvmsg.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

Add a variant of CMSG_DATA that operates on user pointer to avoid
sparse warnings about casting to/from user pointers.  Also fix up
CMSG_DATA to rely on the gcc extension that allows void pointer
arithmetics to cut down on the amount of casts.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

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
  ...

Just like commit 4022e7af86be, this fixes the fact that
IORING_OP_ACCEPT ends up using get_unused_fd_flags(), which checks
current->signal->rlim[] for limits.

Add an extra argument to __sys_accept4_file() that allows us to pass
in the proper nofile limit, and grab it at request prep time.

Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

This splits it into two parts, one that imports the message, and one
that imports the iovec. This allows a caller to only do the first part,
and import the iovec manually afterwards.

No functional changes in this patch.

Acked-by: David Miller <davem@davemloft.net>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Just like commit f67676d160c6 for read/write requests, this one ensures
that the sockaddr data has been copied for IORING_OP_CONNECT if we need
to punt the request to async context.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

Just like commit f67676d160c6 for read/write requests, this one ensures
that the msghdr data is fully copied if we need to punt a recvmsg or
sendmsg system call to async context.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

This is identical to __sys_connect(), except it takes a struct file
instead of an fd, and it also allows passing in extra file->f_flags
flags. The latter is done to support masking in O_NONBLOCK without
manipulating the original file flags.

No functional changes in this patch.

Cc: netdev@vger.kernel.org
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jens Axboe <axboe@kernel.dk>