github.com/pawelgaczynski/giouring@v0.0.0-20230826085535-69588b89acb9/buffer.go (about)

     1  // MIT License
     2  //
     3  // Copyright (c) 2023 Paweł Gaczyński
     4  //
     5  // Permission is hereby granted, free of charge, to any person obtaining a
     6  // copy of this software and associated documentation files (the
     7  // "Software"), to deal in the Software without restriction, including
     8  // without limitation the rights to use, copy, modify, merge, publish,
     9  // distribute, sublicense, and/or sell copies of the Software, and to
    10  // permit persons to whom the Software is furnished to do so, subject to
    11  // the following conditions:
    12  //
    13  // The above copyright notice and this permission notice shall be included
    14  // in all copies or substantial portions of the Software.
    15  //
    16  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
    17  // OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
    18  // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
    19  // IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
    20  // CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
    21  // TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
    22  // SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
    23  
    24  package giouring
    25  
    26  import (
    27  	"sync/atomic"
    28  	"unsafe"
    29  )
    30  
    31  var RingBufStructSize = uint16(unsafe.Sizeof(BufAndRing{}))
    32  
    33  // liburing: io_uring_buf_ring_add - https://manpages.debian.org/unstable/liburing-dev/io_uring_buf_ring_add.3.en.html
    34  func (br *BufAndRing) BufRingAdd(addr uintptr, length uint32, bid uint16, mask, bufOffset int) {
    35  	buf := (*BufAndRing)(
    36  		unsafe.Pointer(uintptr(unsafe.Pointer(br)) +
    37  			(uintptr(((br.Tail + uint16(bufOffset)) & uint16(mask)) * RingBufStructSize))))
    38  	buf.Addr = uint64(addr)
    39  	buf.Len = length
    40  	buf.Bid = bid
    41  }
    42  
    43  const bit16offset = 16
    44  
    45  // liburing: io_uring_buf_ring_advance - https://manpages.debian.org/unstable/liburing-dev/io_uring_buf_ring_advance.3.en.html
    46  func (br *BufAndRing) BufRingAdvance(count int) {
    47  	newTail := br.Tail + uint16(count)
    48  	// FIXME: implement 16 bit version of atomic.Store
    49  	bidAndTail := (*uint32)(unsafe.Pointer(&br.Bid))
    50  	bidAndTailVal := uint32(newTail)<<bit16offset + uint32(br.Bid)
    51  	atomic.StoreUint32(bidAndTail, bidAndTailVal)
    52  }
    53  
    54  // liburing:  __io_uring_buf_ring_cq_advance - https://manpages.debian.org/unstable/liburing-dev/__io_uring_buf_ring_cq_advance.3.en.html
    55  func (ring *Ring) internalBufRingCQAdvance(br *BufAndRing, bufCount, cqeCount int) {
    56  	br.Tail += uint16(bufCount)
    57  	ring.CQAdvance(uint32(cqeCount))
    58  }
    59  
    60  // liburing: io_uring_buf_ring_cq_advance - https://manpages.debian.org/unstable/liburing-dev/io_uring_buf_ring_cq_advance.3.en.html
    61  func (ring *Ring) BufRingCQAdvance(br *BufAndRing, count int) {
    62  	ring.internalBufRingCQAdvance(br, count, count)
    63  }
    64  
    65  // liburing: io_uring_buf_ring_init - https://manpages.debian.org/unstable/liburing-dev/io_uring_buf_ring_init.3.en.html
    66  func (br *BufAndRing) BufRingInit() {
    67  	br.Tail = 0
    68  }
    69  
    70  // liburing: io_uring_buf_ring_mask - https://manpages.debian.org/unstable/liburing-dev/io_uring_buf_ring_mask.3.en.html
    71  func BufRingMask(entries uint32) int {
    72  	return int(entries - 1)
    73  }