interface.c 4.9 KB

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  1. /******************************************************************************
  2. * Block-device interface management.
  3. *
  4. * Copyright (c) 2004, Keir Fraser
  5. *
  6. * This program is free software; you can redistribute it and/or
  7. * modify it under the terms of the GNU General Public License version 2
  8. * as published by the Free Software Foundation; or, when distributed
  9. * separately from the Linux kernel or incorporated into other
  10. * software packages, subject to the following license:
  11. *
  12. * Permission is hereby granted, free of charge, to any person obtaining a copy
  13. * of this source file (the "Software"), to deal in the Software without
  14. * restriction, including without limitation the rights to use, copy, modify,
  15. * merge, publish, distribute, sublicense, and/or sell copies of the Software,
  16. * and to permit persons to whom the Software is furnished to do so, subject to
  17. * the following conditions:
  18. *
  19. * The above copyright notice and this permission notice shall be included in
  20. * all copies or substantial portions of the Software.
  21. *
  22. * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  23. * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  24. * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  25. * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  26. * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  27. * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  28. * IN THE SOFTWARE.
  29. */
  30. #include "common.h"
  31. #include <xen/events.h>
  32. #include <xen/grant_table.h>
  33. #include <linux/kthread.h>
  34. static struct kmem_cache *blkif_cachep;
  35. struct blkif_st *blkif_alloc(domid_t domid)
  36. {
  37. struct blkif_st *blkif;
  38. blkif = kmem_cache_alloc(blkif_cachep, GFP_KERNEL);
  39. if (!blkif)
  40. return ERR_PTR(-ENOMEM);
  41. memset(blkif, 0, sizeof(*blkif));
  42. blkif->domid = domid;
  43. spin_lock_init(&blkif->blk_ring_lock);
  44. atomic_set(&blkif->refcnt, 1);
  45. init_waitqueue_head(&blkif->wq);
  46. blkif->st_print = jiffies;
  47. init_waitqueue_head(&blkif->waiting_to_free);
  48. return blkif;
  49. }
  50. static int map_frontend_page(struct blkif_st *blkif, unsigned long shared_page)
  51. {
  52. struct gnttab_map_grant_ref op;
  53. gnttab_set_map_op(&op, (unsigned long)blkif->blk_ring_area->addr,
  54. GNTMAP_host_map, shared_page, blkif->domid);
  55. if (HYPERVISOR_grant_table_op(GNTTABOP_map_grant_ref, &op, 1))
  56. BUG();
  57. if (op.status) {
  58. DPRINTK(" Grant table operation failure !\n");
  59. return op.status;
  60. }
  61. blkif->shmem_ref = shared_page;
  62. blkif->shmem_handle = op.handle;
  63. return 0;
  64. }
  65. static void unmap_frontend_page(struct blkif_st *blkif)
  66. {
  67. struct gnttab_unmap_grant_ref op;
  68. gnttab_set_unmap_op(&op, (unsigned long)blkif->blk_ring_area->addr,
  69. GNTMAP_host_map, blkif->shmem_handle);
  70. if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, &op, 1))
  71. BUG();
  72. }
  73. int blkif_map(struct blkif_st *blkif, unsigned long shared_page,
  74. unsigned int evtchn)
  75. {
  76. int err;
  77. /* Already connected through? */
  78. if (blkif->irq)
  79. return 0;
  80. blkif->blk_ring_area = alloc_vm_area(PAGE_SIZE);
  81. if (!blkif->blk_ring_area)
  82. return -ENOMEM;
  83. err = map_frontend_page(blkif, shared_page);
  84. if (err) {
  85. free_vm_area(blkif->blk_ring_area);
  86. return err;
  87. }
  88. switch (blkif->blk_protocol) {
  89. case BLKIF_PROTOCOL_NATIVE:
  90. {
  91. struct blkif_sring *sring;
  92. sring = (struct blkif_sring *)blkif->blk_ring_area->addr;
  93. BACK_RING_INIT(&blkif->blk_rings.native, sring, PAGE_SIZE);
  94. break;
  95. }
  96. case BLKIF_PROTOCOL_X86_32:
  97. {
  98. struct blkif_x86_32_sring *sring_x86_32;
  99. sring_x86_32 = (struct blkif_x86_32_sring *)blkif->blk_ring_area->addr;
  100. BACK_RING_INIT(&blkif->blk_rings.x86_32, sring_x86_32, PAGE_SIZE);
  101. break;
  102. }
  103. case BLKIF_PROTOCOL_X86_64:
  104. {
  105. struct blkif_x86_64_sring *sring_x86_64;
  106. sring_x86_64 = (struct blkif_x86_64_sring *)blkif->blk_ring_area->addr;
  107. BACK_RING_INIT(&blkif->blk_rings.x86_64, sring_x86_64, PAGE_SIZE);
  108. break;
  109. }
  110. default:
  111. BUG();
  112. }
  113. err = bind_interdomain_evtchn_to_irqhandler(
  114. blkif->domid, evtchn, blkif_be_int, 0, "blkif-backend", blkif);
  115. if (err < 0) {
  116. unmap_frontend_page(blkif);
  117. free_vm_area(blkif->blk_ring_area);
  118. blkif->blk_rings.common.sring = NULL;
  119. return err;
  120. }
  121. blkif->irq = err;
  122. return 0;
  123. }
  124. void blkif_disconnect(struct blkif_st *blkif)
  125. {
  126. if (blkif->xenblkd) {
  127. kthread_stop(blkif->xenblkd);
  128. blkif->xenblkd = NULL;
  129. }
  130. atomic_dec(&blkif->refcnt);
  131. wait_event(blkif->waiting_to_free, atomic_read(&blkif->refcnt) == 0);
  132. atomic_inc(&blkif->refcnt);
  133. if (blkif->irq) {
  134. unbind_from_irqhandler(blkif->irq, blkif);
  135. blkif->irq = 0;
  136. }
  137. if (blkif->blk_rings.common.sring) {
  138. unmap_frontend_page(blkif);
  139. free_vm_area(blkif->blk_ring_area);
  140. blkif->blk_rings.common.sring = NULL;
  141. }
  142. }
  143. void blkif_free(struct blkif_st *blkif)
  144. {
  145. if (!atomic_dec_and_test(&blkif->refcnt))
  146. BUG();
  147. kmem_cache_free(blkif_cachep, blkif);
  148. }
  149. int __init blkif_interface_init(void)
  150. {
  151. blkif_cachep = kmem_cache_create("blkif_cache", sizeof(struct blkif_st),
  152. 0, 0, NULL);
  153. if (!blkif_cachep)
  154. return -ENOMEM;
  155. return 0;
  156. }