LCOV - code coverage report
Current view: top level - drivers - aio_getevents.c (source / functions) Hit Total Coverage
Test: coverage.info Lines: 0 22 0.0 %
Date: 2025-03-10 18:15:27 Functions: 0 1 0.0 %
Branches: 0 8 0.0 %

           Branch data     Line data    Source code
       1                 :            : /*-
       2                 :            :  *   BSD LICENSE
       3                 :            :  *
       4                 :            :  *   Copyright (c) Intel Corporation.
       5                 :            :  *   All rights reserved.
       6                 :            :  *
       7                 :            :  *   Redistribution and use in source and binary forms, with or without
       8                 :            :  *   modification, are permitted provided that the following conditions
       9                 :            :  *   are met:
      10                 :            :  *
      11                 :            :  *     * Redistributions of source code must retain the above copyright
      12                 :            :  *       notice, this list of conditions and the following disclaimer.
      13                 :            :  *     * Redistributions in binary form must reproduce the above copyright
      14                 :            :  *       notice, this list of conditions and the following disclaimer in
      15                 :            :  *       the documentation and/or other materials provided with the
      16                 :            :  *       distribution.
      17                 :            :  *     * Neither the name of Intel Corporation nor the names of its
      18                 :            :  *       contributors may be used to endorse or promote products derived
      19                 :            :  *       from this software without specific prior written permission.
      20                 :            :  *
      21                 :            :  *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
      22                 :            :  *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
      23                 :            :  *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
      24                 :            :  *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
      25                 :            :  *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
      26                 :            :  *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
      27                 :            :  *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
      28                 :            :  *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
      29                 :            :  *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
      30                 :            :  *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
      31                 :            :  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
      32                 :            :  */
      33                 :            : 
      34                 :            : #include "aio_getevents.h"
      35                 :            : #include "spdk/stdinc.h"
      36                 :            : #include "spdk/barrier.h"
      37                 :            : #include "spdk/likely.h"
      38                 :            : #include "spdk/util.h"
      39                 :            : 
      40                 :            : /* For user space reaping of completions */
      41                 :            : struct spdk_aio_ring {
      42                 :            :         uint32_t id;
      43                 :            :         uint32_t size;
      44                 :            :         uint32_t head;
      45                 :            :         uint32_t tail;
      46                 :            : 
      47                 :            :         uint32_t version;
      48                 :            :         uint32_t compat_features;
      49                 :            :         uint32_t incompat_features;
      50                 :            :         uint32_t header_length;
      51                 :            : };
      52                 :            : 
      53                 :            : #define SPDK_AIO_RING_VERSION   0xa10a10a1
      54                 :            : 
      55                 :          0 : int user_io_getevents(io_context_t io_ctx, unsigned int max, struct io_event *uevents)
      56                 :            : {
      57                 :            :         uint32_t head, tail, count;
      58                 :            :         struct spdk_aio_ring *ring;
      59                 :            :         struct timespec timeout;
      60                 :            :         struct io_event *kevents;
      61                 :            : 
      62                 :          0 :         ring = (struct spdk_aio_ring *)io_ctx;
      63                 :            : 
      64 [ #  # ][ #  # ]:          0 :         if (spdk_unlikely(ring->version != SPDK_AIO_RING_VERSION || ring->incompat_features != 0)) {
      65                 :          0 :                 timeout.tv_sec = 0;
      66                 :          0 :                 timeout.tv_nsec = 0;
      67                 :            : 
      68                 :          0 :                 return io_getevents(io_ctx, 0, max, uevents, &timeout);
      69                 :            :         }
      70                 :            : 
      71                 :            :         /* Read the current state out of the ring */
      72                 :          0 :         head = ring->head;
      73                 :          0 :         tail = ring->tail;
      74                 :            : 
      75                 :            :         /* This memory barrier is required to prevent the loads above
      76                 :            :          * from being re-ordered with stores to the events array
      77                 :            :          * potentially occurring on other threads. */
      78                 :          0 :         spdk_smp_rmb();
      79                 :            : 
      80                 :            :         /* Calculate how many items are in the circular ring */
      81                 :          0 :         count = tail - head;
      82         [ #  # ]:          0 :         if (tail < head) {
      83                 :          0 :                 count += ring->size;
      84                 :            :         }
      85                 :            : 
      86                 :            :         /* Reduce the count to the limit provided by the user */
      87                 :          0 :         count = spdk_min(max, count);
      88                 :            : 
      89                 :            :         /* Grab the memory location of the event array */
      90                 :          0 :         kevents = (struct io_event *)((uintptr_t)ring + ring->header_length);
      91                 :            : 
      92                 :            :         /* Copy the events out of the ring. */
      93         [ #  # ]:          0 :         if ((head + count) <= ring->size) {
      94                 :            :                 /* Only one copy is required */
      95                 :          0 :                 memcpy(uevents, &kevents[head], count * sizeof(struct io_event));
      96                 :            :         } else {
      97                 :          0 :                 uint32_t first_part = ring->size - head;
      98                 :            :                 /* Two copies are required */
      99                 :          0 :                 memcpy(uevents, &kevents[head], first_part * sizeof(struct io_event));
     100                 :          0 :                 memcpy(&uevents[first_part], &kevents[0], (count - first_part) * sizeof(struct io_event));
     101                 :            :         }
     102                 :            : 
     103                 :            :         /* Update the head pointer. On x86, stores will not be reordered with older loads,
     104                 :            :          * so the copies out of the event array will always be complete prior to this
     105                 :            :          * update becoming visible. On other architectures this is not guaranteed, so
     106                 :            :          * add a barrier. */
     107                 :            : #if defined(__i386__) || defined(__x86_64__)
     108                 :          0 :         spdk_compiler_barrier();
     109                 :            : #else
     110                 :            :         spdk_smp_mb();
     111                 :            : #endif
     112                 :          0 :         ring->head = (head + count) % ring->size;
     113                 :            : 
     114                 :          0 :         return count;
     115                 :            : }

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