block: add helper function to determine if a BDS is in a chain

This is a small helper function, to determine if 'base' is in the
chain of BlockDriverState 'top'.  It returns true if it is in the chain,
and false otherwise.

If either argument is NULL, it will also return false.

Reviewed-by: Benoit Canet <benoit@irqsave.net>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2 files changed
tree: a48d938dc87ab82353945528d368d2d700da339e
  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. libdecnumber/
  15. linux-headers/
  16. linux-user/
  17. net/
  18. pc-bios/
  19. po/
  20. qapi/
  21. qga/
  22. qobject/
  23. qom/
  24. roms/
  25. scripts/
  26. slirp/
  27. stubs/
  28. sysconfigs/
  29. target-alpha/
  30. target-arm/
  31. target-cris/
  32. target-i386/
  33. target-lm32/
  34. target-m68k/
  35. target-microblaze/
  36. target-mips/
  37. target-moxie/
  38. target-openrisc/
  39. target-ppc/
  40. target-s390x/
  41. target-sh4/
  42. target-sparc/
  43. target-unicore32/
  44. target-xtensa/
  45. tcg/
  46. tests/
  47. trace/
  48. ui/
  49. util/
  50. .exrc
  51. .gitignore
  52. .gitmodules
  53. .mailmap
  54. .travis.yml
  55. aio-posix.c
  56. aio-win32.c
  57. arch_init.c
  58. async.c
  59. balloon.c
  60. block-migration.c
  61. block.c
  62. blockdev-nbd.c
  63. blockdev.c
  64. blockjob.c
  65. bt-host.c
  66. bt-vhci.c
  67. Changelog
  68. CODING_STYLE
  69. configure
  70. COPYING
  71. COPYING.LIB
  72. coroutine-gthread.c
  73. coroutine-sigaltstack.c
  74. coroutine-ucontext.c
  75. coroutine-win32.c
  76. cpu-exec.c
  77. cpus.c
  78. cputlb.c
  79. device-hotplug.c
  80. device_tree.c
  81. disas.c
  82. dma-helpers.c
  83. dump.c
  84. exec.c
  85. gdbstub.c
  86. HACKING
  87. hmp-commands.hx
  88. hmp.c
  89. hmp.h
  90. iohandler.c
  91. ioport.c
  92. iothread.c
  93. kvm-all.c
  94. kvm-stub.c
  95. LICENSE
  96. main-loop.c
  97. MAINTAINERS
  98. Makefile
  99. Makefile.objs
  100. Makefile.target
  101. memory.c
  102. memory_mapping.c
  103. migration-exec.c
  104. migration-fd.c
  105. migration-rdma.c
  106. migration-tcp.c
  107. migration-unix.c
  108. migration.c
  109. module-common.c
  110. monitor.c
  111. nbd.c
  112. numa.c
  113. os-posix.c
  114. os-win32.c
  115. page_cache.c
  116. qapi-schema.json
  117. qdev-monitor.c
  118. qdict-test-data.txt
  119. qemu-bridge-helper.c
  120. qemu-char.c
  121. qemu-coroutine-io.c
  122. qemu-coroutine-lock.c
  123. qemu-coroutine-sleep.c
  124. qemu-coroutine.c
  125. qemu-doc.texi
  126. qemu-file.c
  127. qemu-img-cmds.hx
  128. qemu-img.c
  129. qemu-img.texi
  130. qemu-io-cmds.c
  131. qemu-io.c
  132. qemu-log.c
  133. qemu-nbd.c
  134. qemu-nbd.texi
  135. qemu-options-wrapper.h
  136. qemu-options.h
  137. qemu-options.hx
  138. qemu-seccomp.c
  139. qemu-tech.texi
  140. qemu-timer.c
  141. qemu.nsi
  142. qemu.sasl
  143. qmp-commands.hx
  144. qmp.c
  145. qtest.c
  146. README
  147. rules.mak
  148. savevm.c
  149. softmmu_template.h
  150. spice-qemu-char.c
  151. tcg-runtime.c
  152. tci.c
  153. thread-pool.c
  154. thunk.c
  155. tpm.c
  156. trace-events
  157. translate-all.c
  158. translate-all.h
  159. user-exec.c
  160. VERSION
  161. version.rc
  162. vl.c
  163. vmstate.c
  164. xbzrle.c
  165. xen-common-stub.c
  166. xen-common.c
  167. xen-hvm-stub.c
  168. xen-hvm.c
  169. xen-mapcache.c