user/sven/linux.git/include/linux/uio.h, branch v5.5.8

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

Merge tag 'io_uring-20190323' of git://git.kernel.dk/linux-block

2019-03-23T17:25:12Z

Pull io_uring fixes and improvements from Jens Axboe: "The first five in this series are heavily inspired by the work Al did on the aio side to fix the races there. The last two re-introduce a feature that was in io_uring before it got merged, but which I pulled since we didn't have a good way to have BVEC iters that already have a stable reference. These aren't necessarily related to block, it's just how io_uring pins fixed buffers" * tag 'io_uring-20190323' of git://git.kernel.dk/linux-block: block: add BIO_NO_PAGE_REF flag iov_iter: add ITER_BVEC_FLAG_NO_REF flag io_uring: mark me as the maintainer io_uring: retry bulk slab allocs as single allocs io_uring: fix poll races io_uring: fix fget/fput handling io_uring: add prepped flag io_uring: make io_read/write return an integer io_uring: use regular request ref counts

iov_iter: add ITER_BVEC_FLAG_NO_REF flag

2019-03-18T16:44:48Z

For ITER_BVEC, if we're holding on to kernel pages, the caller doesn't need to grab a reference to the bvec pages, and drop that same reference on IO completion. This is essentially safe for any ITER_BVEC, but some use cases end up reusing pages and uncondtionally dropping a page reference on completion. And example of that is sendfile(2), that ends up being a splice_in + splice_out on the pipe pages. Add a flag that tells us it's fine to not grab a page reference to the bvec pages, since that caller knows not to drop a reference when it's done with the pages. Signed-off-by: Jens Axboe

uio: remove the unused iov_for_each macro

2019-02-04T15:59:50Z

Signed-off-by: Christoph Hellwig Signed-off-by: Al Viro

iov_iter: introduce hash_and_copy_to_iter helper

2018-12-13T08:58:54Z

Allow consumers that want to use iov iterator helpers and also update a predefined hash calculation online when copying data. This is useful when copying incoming network buffers to a local iterator and calculate a digest on the incoming stream. nvme-tcp host driver that will be introduced in following patches is the first consumer via skb_copy_and_hash_datagram_iter. Acked-by: David S. Miller Signed-off-by: Sagi Grimberg Signed-off-by: Christoph Hellwig