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This is an automatically generated e-mail. To reply, visit:
<a href="https://git.reviewboard.kde.org/r/130090/">https://git.reviewboard.kde.org/r/130090/</a>
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<p style="margin-top: 0;">On April 18th, 2017, 9:45 p.m. UTC, <b>Lamarque Souza</b> wrote:</p>
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<a href="https://git.reviewboard.kde.org/r/130090/diff/1/?file=494454#file494454line31" style="color: black; font-weight: bold; text-decoration: underline;">src/solid/devices/backends/udisks2/udisksblock.cpp</a>
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(Diff revision 1)
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<td bgcolor="#fdfebc" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="cp">#define MINORBITS 20</span></pre></td>
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<td bgcolor="#fdfebc" width="50%"><pre style="font-size: 8pt; line-height: 140%; margin: 0; "><span class="cp">#define major(dev) ((dev)>>8)</span></pre></td>
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<pre style="white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;"><p style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">Usually we use uppper case for macros. That would also save some lines in this patch.</p>
<p style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">nitpik: add spaces around >>, like you did for & in the line below.</p></pre>
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<p>On April 19th, 2017, 7:24 a.m. UTC, <b>KJ Tsanaktsidis</b> wrote:</p>
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<pre style="white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;"><p style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">Thanks for the review.</p>
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<li style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: normal;">I would use upper case, but the macro is defined in <code style="text-rendering: inherit;color: #4444cc;padding: 0;white-space: normal;margin: 0;line-height: inherit;">sys/sysmacros.h</code> and <code style="text-rendering: inherit;color: #4444cc;padding: 0;white-space: normal;margin: 0;line-height: inherit;">sys/types.h</code> in lowercase. See https://code.woboq.org/userspace/glibc/misc/sys/sysmacros.h.html.</li>
<li style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: normal;">I'm happy enough to fix the formatting issue with <code style="text-rendering: inherit;color: #4444cc;padding: 0;white-space: normal;margin: 0;line-height: inherit;">>></code>.</li>
<li style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: normal;">I'm also halfway through writing a testcase for this - the udisks2 stuff is untested so I figured it would be worth going through the motion and setting up the test framework for it even just for this to make adding further test coverage useful. I'll add that to this patch when I finish it either tonight or tomorrow.</li>
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<pre style="margin-left: 1em; white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;"><p style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">OK - I've addressed the formatting issue and added a testcase. Also the link in my comment above is wrong because it has a trailing full-stop - should be https://code.woboq.org/userspace/glibc/misc/sys/sysmacros.h.html</p></pre>
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<p>- KJ</p>
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<p>On April 19th, 2017, 11:05 a.m. UTC, KJ Tsanaktsidis wrote:</p>
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<div>Review request for KDE Frameworks.</div>
<div>By KJ Tsanaktsidis.</div>
<p style="color: grey;"><i>Updated April 19, 2017, 11:05 a.m.</i></p>
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<b style="color: #575012; font-size: 10pt;">Repository: </b>
solid
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<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Description </h1>
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<pre style="margin: 0; padding: 0; white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;">Previously, udesksblock.cpp was attempting to find a definition for
major/minor on Linux in <sys/kdev_t.h> by checking Q_OS_LINUX before
importing the header. Q_OS_LINUX is however only set when
qsystemdetection.h is included, and the macro was being checked first.
Even had this check worked, it would still be wrong. On a modern version
of the userspace linux-headers, <sys/kdev_t.h> includes definitions for
major and minor that assume each is limited to 8 bits and that dev_t is
16 bits. This is no longer true anymore; on Linux, major numbers can be
up to 12 bits at present and minor numbers up to 20. Calling these
macros with dev_t values > 2^16 would give incorrect results.
Because the Q_OS_LINUX check failed, a fallback version of the macros
were defined for use on all platforms. The code is allegedly copied from
kdev_t.h, except it is copied from the *kernel* version of the header,
not the userspace version. Linux internally uses a different
representation of dev_t than it exposes to userspace - the kernelspace
version is 20 bits of minor/12 bits of major contiguously, but the
userspace version packs the bits in a different order to maintain
compatability with old 16-bit device numbers. Thus, this code also does
not work for dev_t values > 2^16.
To fix this, we add CMake rules to search for a system-provided
definition of the major/minor macros - on various systems, these can be
in a few different places. As a fallback, we assume old-style 16-bit
dev_t (although I suspect that is only used for Windows, where
major/minor numbers are pretty meaningless anyway).</pre>
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<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Testing </h1>
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<pre style="margin: 0; padding: 0; white-space: pre-wrap; white-space: -moz-pre-wrap; white-space: -pre-wrap; white-space: -o-pre-wrap; word-wrap: break-word;"><p style="padding: 0;text-rendering: inherit;margin: 0;line-height: inherit;white-space: inherit;">I've written a little snippet to iterate through block devices, print their major/minor number, and their device properties. It was previously incorrectly labeling all my disks with major 0 and minor == device_number (since it was using the first 20 bits for the minor). It now correctly identifies their major/minor number.</p></pre>
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<h1 style="color: #575012; font-size: 10pt; margin-top: 1.5em;">Diffs</b> </h1>
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<li>autotests/CMakeLists.txt <span style="color: grey">(54adeea62b954b9169b37f1eab8fa3e215fafafa)</span></li>
<li>autotests/fakeUdisks2.h <span style="color: grey">(PRE-CREATION)</span></li>
<li>autotests/fakeUdisks2.cpp <span style="color: grey">(PRE-CREATION)</span></li>
<li>autotests/solidudisks2test.cpp <span style="color: grey">(PRE-CREATION)</span></li>
<li>src/solid/devices/backends/udisks2/CMakeLists.txt <span style="color: grey">(34390064af29ace07cbb3470945be098cc606d04)</span></li>
<li>src/solid/devices/backends/udisks2/udisksblock.cpp <span style="color: grey">(0622ec77fcf670a2005d34b7a6c31ca8b53a18d8)</span></li>
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<p><a href="https://git.reviewboard.kde.org/r/130090/diff/" style="margin-left: 3em;">View Diff</a></p>
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