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android / platform / external / fio / 400531d97395b64e416e0adfdb041419d3994621
commit400531d97395b64e416e0adfdb041419d3994621[log] [tgz]
authorJens Axboe <axboe@fb.com>Tue Dec 16 22:40:37 2014 -0700
committerMohamad Ayyash <mkayyash@google.com>Fri Mar 06 17:58:09 2015 -0800
treeb71e99c487e4e7be72833cb8c871338212d67e99
parent80ac020b479bd433590d221fcefa3eb47327f9a3 [diff]
gettime: fix overflow in cycle to usec conversion

If this multiplication overflows:

usecs = (t * inv_cycles_per_usec) / 16777216UL;

then usecs is 2^64/2^24, which is 1099511627776. Divide that by
10^6 to get seconds, and that is 1099511. Since we cached the
old value previously, we'd get stuck with this amount of seconds.

To avoid turning this into an expensive division, have a check
and only divide if we have to. This avoids the overflow.

Signed-off-by: Jens Axboe <axboe@fb.com>
1 file changed
tree: b71e99c487e4e7be72833cb8c871338212d67e99
  1. arch/
  2. compiler/
  3. crc/
  4. engines/
  5. examples/
  6. exp/
  7. lib/
  8. os/
  9. profiles/
  10. t/
  11. tools/
  12. .gitignore
  13. Android.mk
  14. backend.c
  15. blktrace.c
  16. blktrace_api.h
  17. cairo_text_helpers.c
  18. cairo_text_helpers.h
  19. cconv.c
  20. cgroup.c
  21. cgroup.h
  22. client.c
  23. client.h
  24. configure
  25. COPYING
  26. debug.c
  27. debug.h
  28. diskutil.c
  29. diskutil.h
  30. err.h
  31. eta.c
  32. fifo.c
  33. fifo.h
  34. file.h
  35. filehash.c
  36. filehash.h
  37. filelock.c
  38. filelock.h
  39. filesetup.c
  40. FIO-VERSION-GEN
  41. fio.1
  42. fio.c
  43. fio.h
  44. fio_time.h
  45. flist.h
  46. flow.c
  47. flow.h
  48. gclient.c
  49. gclient.h
  50. gcompat.c
  51. gcompat.h
  52. gerror.c
  53. gerror.h
  54. gettime-thread.c
  55. gettime.c
  56. gettime.h
  57. GFIO-TODO
  58. gfio.c
  59. gfio.h
  60. ghelpers.c
  61. ghelpers.h
  62. goptions.c
  63. goptions.h
  64. graph.c
  65. graph.h
  66. hash.h
  67. helpers.c
  68. helpers.h
  69. HOWTO
  70. idletime.c
  71. idletime.h
  72. init.c
  73. io_ddir.h
  74. io_u.c
  75. io_u_queue.c
  76. io_u_queue.h
  77. ioengine.h
  78. ioengines.c
  79. iolog.c
  80. iolog.h
  81. json.c
  82. json.h
  83. libfio.c
  84. LICENSE
  85. log.c
  86. log.h
  87. Makefile
  88. memalign.c
  89. memalign.h
  90. memory.c
  91. minmax.h
  92. MODULE_LICENSE_GPL
  93. mutex.c
  94. mutex.h
  95. NOTICE
  96. options.c
  97. options.h
  98. parse.c
  99. parse.h
  100. printing.c
  101. printing.h
  102. profile.c
  103. profile.h
  104. README
  105. REPORTING-BUGS
  106. SERVER-TODO
  107. server.c
  108. server.h
  109. smalloc.c
  110. smalloc.h
  111. stat.c
  112. stat.h
  113. td_error.c
  114. td_error.h
  115. thread_options.h
  116. tickmarks.c
  117. tickmarks.h
  118. time.c
  119. trim.c
  120. trim.h
  121. verify.c
  122. verify.h