qom: Make QOM link property unref optional

Some object_property_add_link() callers expect property deletion to
unref the link property object.  Other callers expect to manage the
refcount themselves.  The former are currently broken and therefore leak
the link property object.

This patch adds a flags argument to object_property_add_link() so the
caller can specify which refcount behavior they require.  The new
OBJ_PROP_LINK_UNREF_ON_RELEASE flag causes the link pointer to be
unreferenced when the property is deleted.

This fixes refcount leaks in qdev.c, xilinx_axidma.c, xilinx_axienet.c,
s390-virtio-bus.c, virtio-pci.c, virtio-rng.c, and ui/console.c.

Rationale for refcount behavior:

 * hw/core/qdev.c
   - bus children are explicitly unreferenced, don't interfere
   - parent_bus is essentially a read-only property that doesn't hold a
     refcount, don't unref
   - hotplug_handler is leaked, do unref

 * hw/dma/xilinx_axidma.c
   - rx stream "dma" links are set using set_link, therefore they
     need unref
   - tx streams are set using set_link, therefore they need unref

 * hw/net/xilinx_axienet.c
   - same reasoning as hw/dma/xilinx_axidma.c

 * hw/pcmcia/pxa2xx.c
   - pxa2xx bypasses set_link and therefore does not use refcounts

 * hw/s390x/s390-virtio-bus.c
 * hw/virtio/virtio-pci.c
 * hw/virtio/virtio-rng.c
 * ui/console.c
   - set_link is used and there is no explicit unref, do unref

Cc: Peter Crosthwaite <peter.crosthwaite@petalogix.com>
Cc: Alexander Graf <agraf@suse.de>
Cc: Anthony Liguori <aliguori@amazon.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
11 files changed
tree: ca7896ed13382ba841ec2af894b1cee65c1a3dae
  1. audio/
  2. backends/
  3. block/
  4. bsd-user/
  5. default-configs/
  6. disas/
  7. docs/
  8. fpu/
  9. fsdev/
  10. gdb-xml/
  11. hw/
  12. include/
  13. libcacard/
  14. linux-headers/
  15. linux-user/
  16. net/
  17. pc-bios/
  18. po/
  19. qapi/
  20. qga/
  21. qobject/
  22. qom/
  23. roms/
  24. scripts/
  25. slirp/
  26. stubs/
  27. sysconfigs/
  28. target-alpha/
  29. target-arm/
  30. target-cris/
  31. target-i386/
  32. target-lm32/
  33. target-m68k/
  34. target-microblaze/
  35. target-mips/
  36. target-moxie/
  37. target-openrisc/
  38. target-ppc/
  39. target-s390x/
  40. target-sh4/
  41. target-sparc/
  42. target-unicore32/
  43. target-xtensa/
  44. tcg/
  45. tests/
  46. trace/
  47. ui/
  48. util/
  49. .exrc
  50. .gitignore
  51. .gitmodules
  52. .mailmap
  53. .travis.yml
  54. aio-posix.c
  55. aio-win32.c
  56. arch_init.c
  57. async.c
  58. balloon.c
  59. block-migration.c
  60. block.c
  61. blockdev-nbd.c
  62. blockdev.c
  63. blockjob.c
  64. bt-host.c
  65. bt-vhci.c
  66. Changelog
  67. CODING_STYLE
  68. configure
  69. COPYING
  70. COPYING.LIB
  71. coroutine-gthread.c
  72. coroutine-sigaltstack.c
  73. coroutine-ucontext.c
  74. coroutine-win32.c
  75. cpu-exec.c
  76. cpus.c
  77. cputlb.c
  78. device-hotplug.c
  79. device_tree.c
  80. disas.c
  81. dma-helpers.c
  82. dump.c
  83. exec.c
  84. gdbstub.c
  85. HACKING
  86. hmp-commands.hx
  87. hmp.c
  88. hmp.h
  89. iohandler.c
  90. ioport.c
  91. iothread.c
  92. kvm-all.c
  93. kvm-stub.c
  94. LICENSE
  95. main-loop.c
  96. MAINTAINERS
  97. Makefile
  98. Makefile.objs
  99. Makefile.target
  100. memory.c
  101. memory_mapping.c
  102. migration-exec.c
  103. migration-fd.c
  104. migration-rdma.c
  105. migration-tcp.c
  106. migration-unix.c
  107. migration.c
  108. module-common.c
  109. monitor.c
  110. nbd.c
  111. os-posix.c
  112. os-win32.c
  113. page_cache.c
  114. qapi-schema.json
  115. qdev-monitor.c
  116. qdict-test-data.txt
  117. qemu-bridge-helper.c
  118. qemu-char.c
  119. qemu-coroutine-io.c
  120. qemu-coroutine-lock.c
  121. qemu-coroutine-sleep.c
  122. qemu-coroutine.c
  123. qemu-doc.texi
  124. qemu-file.c
  125. qemu-img-cmds.hx
  126. qemu-img.c
  127. qemu-img.texi
  128. qemu-io-cmds.c
  129. qemu-io.c
  130. qemu-log.c
  131. qemu-nbd.c
  132. qemu-nbd.texi
  133. qemu-options-wrapper.h
  134. qemu-options.h
  135. qemu-options.hx
  136. qemu-seccomp.c
  137. qemu-tech.texi
  138. qemu-timer.c
  139. qemu.nsi
  140. qemu.sasl
  141. qmp-commands.hx
  142. qmp.c
  143. qtest.c
  144. README
  145. rules.mak
  146. savevm.c
  147. spice-qemu-char.c
  148. tcg-runtime.c
  149. tci.c
  150. thread-pool.c
  151. thunk.c
  152. tpm.c
  153. trace-events
  154. translate-all.c
  155. translate-all.h
  156. user-exec.c
  157. VERSION
  158. version.rc
  159. vl.c
  160. vmstate.c
  161. xbzrle.c
  162. xen-all.c
  163. xen-mapcache.c
  164. xen-stub.c