user/sven/linux.git/include/linux/uio.h, branch v5.9.8

x86, powerpc: Rename memcpy_mcsafe() to copy_mc_to_{user, kernel}()

2020-11-04T17:09:05Z

commit ec6347bb43395cb92126788a1a5b25302543f815 upstream. In reaction to a proposal to introduce a memcpy_mcsafe_fast() implementation Linus points out that memcpy_mcsafe() is poorly named relative to communicating the scope of the interface. Specifically what addresses are valid to pass as source, destination, and what faults / exceptions are handled. Of particular concern is that even though x86 might be able to handle the semantics of copy_mc_to_user() with its common copy_user_generic() implementation other archs likely need / want an explicit path for this case: On Fri, May 1, 2020 at 11:28 AM Linus Torvalds wrote: > > On Thu, Apr 30, 2020 at 6:21 PM Dan Williams wrote: > > > > However now I see that copy_user_generic() works for the wrong reason. > > It works because the exception on the source address due to poison > > looks no different than a write fault on the user address to the > > caller, it's still just a short copy. So it makes copy_to_user() work > > for the wrong reason relative to the name. > > Right. > > And it won't work that way on other architectures. On x86, we have a > generic function that can take faults on either side, and we use it > for both cases (and for the "in_user" case too), but that's an > artifact of the architecture oddity. > > In fact, it's probably wrong even on x86 - because it can hide bugs - > but writing those things is painful enough that everybody prefers > having just one function. Replace a single top-level memcpy_mcsafe() with either copy_mc_to_user(), or copy_mc_to_kernel(). Introduce an x86 copy_mc_fragile() name as the rename for the low-level x86 implementation formerly named memcpy_mcsafe(). It is used as the slow / careful backend that is supplanted by a fast copy_mc_generic() in a follow-on patch. One side-effect of this reorganization is that separating copy_mc_64.S to its own file means that perf no longer needs to track dependencies for its memcpy_64.S benchmarks. [ bp: Massage a bit. ] Signed-off-by: Dan Williams Signed-off-by: Borislav Petkov Reviewed-by: Tony Luck Acked-by: Michael Ellerman Cc: Link: http://lore.kernel.org/r/CAHk-=wjSqtXAqfUJxFtWNwmguFASTgB0dz1dT3V-78Quiezqbg@mail.gmail.com Link: https://lkml.kernel.org/r/160195561680.2163339.11574962055305783722.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Greg Kroah-Hartman

Revert "x86, powerpc: Rename memcpy_mcsafe() to copy_mc_to_{user, kernel}()"

2020-11-04T17:08:28Z

This reverts commit a85748ed9eb70108f9605558f2754ca94ee91401 which is commit ec6347bb43395cb92126788a1a5b25302543f815 upstream. We had a mistake when merging a later patch in this series due to some file movements, so revert this change for now, as we will add it back in a later commit. Signed-off-by: Greg Kroah-Hartman

x86, powerpc: Rename memcpy_mcsafe() to copy_mc_to_{user, kernel}()

2020-11-01T11:47:03Z

iov_iter: Move unnecessary inclusion of crypto/hash.h

2020-06-30T13:34:23Z

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 Signed-off-by: Al Viro

pipe: Use head and tail pointers for the ring, not cursor and length

2019-10-31T15:12:34Z

Convert pipes to use head and tail pointers for the buffer ring rather than pointer and length as the latter requires two atomic ops to update (or a combined op) whereas the former only requires one. (1) The head pointer is the point at which production occurs and points to the slot in which the next buffer will be placed. This is equivalent to pipe->curbuf + pipe->nrbufs. The head pointer belongs to the write-side. (2) The tail pointer is the point at which consumption occurs. It points to the next slot to be consumed. This is equivalent to pipe->curbuf. The tail pointer belongs to the read-side. (3) head and tail are allowed to run to UINT_MAX and wrap naturally. They are only masked off when the array is being accessed, e.g.: pipe->bufs[head & mask] This means that it is not necessary to have a dead slot in the ring as head == tail isn't ambiguous. (4) The ring is empty if "head == tail". A helper, pipe_empty(), is provided for this. (5) The occupancy of the ring is "head - tail". A helper, pipe_occupancy(), is provided for this. (6) The number of free slots in the ring is "pipe->ring_size - occupancy". A helper, pipe_space_for_user() is provided to indicate how many slots userspace may use. (7) The ring is full if "head - tail >= pipe->ring_size". A helper, pipe_full(), is provided for this. Signed-off-by: David Howells

Merge tag 'for-5.3/io_uring-20190711' of git://git.kernel.dk/linux-block

2019-07-13T17:36:53Z

Pull io_uring updates from Jens Axboe: "This contains: - Support for recvmsg/sendmsg as first class opcodes. I don't envision going much further down this path, as there are plans in progress to support potentially any system call in an async fashion through io_uring. But I think it does make sense to have certain core ops available directly, especially those that can support a "try this non-blocking" flag/mode. (me) - Handle generic short reads automatically. This can happen fairly easily if parts of the buffered read is cached. Since the application needs to issue another request for the remainder, just do this internally and save kernel/user roundtrip while providing a nicer more robust API. (me) - Support for linked SQEs. This allows SQEs to depend on each other, enabling an application to eg queue a read-from-this-file,write-to-that-file pair. (me) - Fix race in stopping SQ thread (Jackie)" * tag 'for-5.3/io_uring-20190711' of git://git.kernel.dk/linux-block: io_uring: fix io_sq_thread_stop running in front of io_sq_thread io_uring: add support for recvmsg() io_uring: add support for sendmsg() io_uring: add support for sqe links io_uring: punt short reads to async context uio: make import_iovec()/compat_import_iovec() return bytes on success

block: never take page references for ITER_BVEC

2019-06-29T15:47:32Z

If we pass pages through an iov_iter we always already have a reference in the caller. Thus remove the ITER_BVEC_FLAG_NO_REF and don't take reference to pages by default for bvec backed iov_iters. Reviewed-by: Minwoo Im Reviewed-by: Johannes Thumshirn Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe

uio: make import_iovec()/compat_import_iovec() return bytes on success

2019-05-31T21:30:03Z

Currently these functions return < 0 on error, and 0 for success. Change that so that we return < 0 on error, but number of bytes for success. Some callers already treat the return value that way, others need a slight tweak. Signed-off-by: Jens Axboe

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

2019-05-30T18:26:32Z

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman

iov_iter: fix iov_iter_type

2019-05-01T14:38:47Z

Commit 875f1d0769cd ("iov_iter: add ITER_BVEC_FLAG_NO_REF flag") introduces one extra flag of ITER_BVEC_FLAG_NO_REF, and this flag is stored into iter->type. However, iov_iter_type() doesn't consider the new added flag, fix it by masking this flag in iov_iter_type(). Fixes: 875f1d0769cd ("iov_iter: add ITER_BVEC_FLAG_NO_REF flag") Reviewed-by: Christoph Hellwig Signed-off-by: Ming Lei Signed-off-by: Jens Axboe