Yida Wang | 0bf43bd | 2017-03-22 18:16:31 -0400 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) 2014-2015, 2017, The Linux Foundation. All rights reserved. |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or modify |
| 5 | * it under the terms of the GNU General Public License version 2 and |
| 6 | * only version 2 as published by the Free Software Foundation. |
| 7 | * |
| 8 | * This program is distributed in the hope that it will be useful, |
| 9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 11 | * GNU General Public License for more details. |
| 12 | */ |
| 13 | |
| 14 | #define pr_fmt(fmt) "seemp: %s: " fmt, __func__ |
| 15 | |
| 16 | #include "seemp_logk.h" |
| 17 | #include "seemp_ringbuf.h" |
| 18 | #include "seemp_event_encoder.h" |
| 19 | |
| 20 | /*initial function no need to hold ring_lock*/ |
| 21 | int ringbuf_init(struct seemp_logk_dev *sdev) |
| 22 | { |
| 23 | char *buf; |
| 24 | unsigned long virt_addr; |
| 25 | |
| 26 | if (kmalloc_flag) { |
| 27 | sdev->ring = kmalloc(sdev->ring_sz, GFP_KERNEL); |
| 28 | if (sdev->ring == NULL) { |
| 29 | pr_err("kmalloc failed, ring_sz= %d\n", sdev->ring_sz); |
| 30 | return -ENOMEM; |
| 31 | } |
| 32 | |
| 33 | buf = (char *)sdev->ring; |
| 34 | |
| 35 | /*reserve kmalloc memory as pages to make them remapable*/ |
| 36 | for (virt_addr = (unsigned long)buf; |
| 37 | virt_addr < (unsigned long)buf + sdev->ring_sz; |
| 38 | virt_addr += PAGE_SIZE) { |
| 39 | SetPageReserved(virt_to_page((virt_addr))); |
| 40 | } |
| 41 | } else { |
| 42 | sdev->ring = vmalloc(sdev->ring_sz); |
| 43 | if (sdev->ring == NULL) { |
| 44 | pr_err("vmalloc failed, ring_sz = %d\n", sdev->ring_sz); |
| 45 | return -ENOMEM; |
| 46 | } |
| 47 | buf = (char *)sdev->ring; |
| 48 | |
| 49 | /*reserve vmalloc memory as pages to make them remapable*/ |
| 50 | for (virt_addr = (unsigned long)buf; |
| 51 | virt_addr < (unsigned long)buf + sdev->ring_sz; |
| 52 | virt_addr += PAGE_SIZE) { |
| 53 | SetPageReserved(vmalloc_to_page( |
| 54 | (unsigned long *) virt_addr)); |
| 55 | } |
| 56 | } |
| 57 | |
| 58 | memset(sdev->ring, 0, sdev->ring_sz); |
| 59 | |
| 60 | sdev->num_tot_blks = (sdev->ring_sz / BLK_SIZE); |
| 61 | sdev->num_writers = 0; |
| 62 | sdev->write_idx = 0; |
| 63 | sdev->read_idx = 0; |
| 64 | |
| 65 | sdev->num_write_avail_blks = sdev->num_tot_blks; |
| 66 | /*no. of blocks available for write*/ |
| 67 | sdev->num_write_in_prog_blks = 0; |
| 68 | /*no. of blocks held by writers to perform writes*/ |
| 69 | |
| 70 | sdev->num_read_avail_blks = 0; |
| 71 | /*no. of blocks ready for read*/ |
| 72 | sdev->num_read_in_prog_blks = 0; |
| 73 | /*no. of blocks held by the reader to perform read*/ |
| 74 | |
| 75 | return 0; |
| 76 | } |
| 77 | |
| 78 | void ringbuf_cleanup(struct seemp_logk_dev *sdev) |
| 79 | { |
| 80 | unsigned long virt_addr; |
| 81 | |
| 82 | if (kmalloc_flag) { |
| 83 | for (virt_addr = (unsigned long)sdev->ring; |
| 84 | virt_addr < (unsigned long)sdev->ring + sdev->ring_sz; |
| 85 | virt_addr += PAGE_SIZE) { |
| 86 | /*clear all pages*/ |
| 87 | ClearPageReserved(virt_to_page((unsigned long *) |
| 88 | virt_addr)); |
| 89 | } |
| 90 | kfree(sdev->ring); |
| 91 | } else { |
| 92 | for (virt_addr = (unsigned long)sdev->ring; |
| 93 | virt_addr < (unsigned long)sdev->ring + sdev->ring_sz; |
| 94 | virt_addr += PAGE_SIZE) { |
| 95 | /*clear all pages*/ |
| 96 | ClearPageReserved(vmalloc_to_page((unsigned long *) |
| 97 | virt_addr)); |
| 98 | } |
| 99 | vfree(sdev->ring); |
| 100 | } |
| 101 | } |
| 102 | |
| 103 | struct seemp_logk_blk *ringbuf_fetch_wr_block |
| 104 | (struct seemp_logk_dev *sdev) |
| 105 | { |
| 106 | struct seemp_logk_blk *blk = NULL; |
| 107 | int idx; |
| 108 | |
| 109 | mutex_lock(&sdev->lock); |
| 110 | if (sdev->num_write_avail_blks == 0) { |
| 111 | idx = -1; |
| 112 | mutex_unlock(&sdev->lock); |
| 113 | return blk; |
| 114 | } |
| 115 | |
| 116 | idx = sdev->write_idx; |
| 117 | sdev->write_idx = (sdev->write_idx + 1) % sdev->num_tot_blks; |
| 118 | sdev->num_write_avail_blks--; |
| 119 | sdev->num_write_in_prog_blks++; |
| 120 | sdev->num_writers++; |
| 121 | |
| 122 | blk = &sdev->ring[idx]; |
| 123 | blk->status = 0x0; |
| 124 | |
| 125 | mutex_unlock(&sdev->lock); |
| 126 | return blk; |
| 127 | } |
| 128 | |
| 129 | void ringbuf_finish_writer(struct seemp_logk_dev *sdev, |
| 130 | struct seemp_logk_blk *blk) |
| 131 | { |
| 132 | /* Encode seemp parameters in multi-threaded mode (before mutex lock) */ |
| 133 | encode_seemp_params(blk); |
| 134 | |
| 135 | /* |
| 136 | * finish writing... |
| 137 | * the calling process will no longer access this block. |
| 138 | */ |
| 139 | mutex_lock(&sdev->lock); |
| 140 | |
| 141 | sdev->num_writers--; |
| 142 | sdev->num_write_in_prog_blks--; |
| 143 | sdev->num_read_avail_blks++; |
| 144 | |
| 145 | /*wake up any readers*/ |
| 146 | if (sdev->num_writers == 0) |
| 147 | wake_up_interruptible(&sdev->readers_wq); |
| 148 | |
| 149 | mutex_unlock(&sdev->lock); |
| 150 | } |
| 151 | |
| 152 | int ringbuf_count_marked(struct seemp_logk_dev *sdev) |
| 153 | { |
| 154 | int i; |
| 155 | unsigned int marked; |
| 156 | |
| 157 | mutex_lock(&sdev->lock); |
| 158 | for (marked = 0, i = 0; i < sdev->num_tot_blks; i++) |
| 159 | if (sdev->ring[i].status & 0x1) |
| 160 | marked++; |
| 161 | mutex_unlock(&sdev->lock); |
| 162 | |
| 163 | return marked; |
| 164 | } |