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author | Jiri Slaby <jslaby@suse.cz> | 2021-05-05 11:19:06 +0200 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-05-13 16:57:16 +0200 |
commit | 64d608db38ffc0c7a25455387096e0aad9410397 (patch) | |
tree | 356a8ff491e272f0d497c9da4401c7f0827c425d /drivers/pps | |
parent | 6e94dbc7a4e49a028b81302d755bba1a518f973b (diff) | |
download | lwn-64d608db38ffc0c7a25455387096e0aad9410397.tar.gz lwn-64d608db38ffc0c7a25455387096e0aad9410397.zip |
tty: cumulate and document tty_struct::ctrl* members
Group the ctrl members under a single struct called ctrl. The new struct
contains 'pgrp', 'session', 'pktstatus', and 'packet'. 'pktstatus' and
'packet' used to be bits in a bitfield. The struct also contains the
lock protecting them to share the same cache line.
Note that commit c545b66c6922b (tty: Serialize tcflow() with other tty
flow control changes) added a padding to the original bitfield. It was
for the bitfield to occupy a whole 64b word to avoid interferring stores
on Alpha (cannot we evaporate this arch with weird implications to C
code yet?). But it doesn't work as expected as the padding
(tty_struct::ctrl_unused) is aligned to a 8B boundary too and occupies
some bytes from the next word.
So make it reliable by:
1) setting __aligned of the struct -- that aligns the start, and
2) making 'unsigned long unused[0]' as the last member of the struct --
pads the end.
Add a kerneldoc comment for this grouped members.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: netdev@vger.kernel.org
Link: https://lore.kernel.org/r/20210505091928.22010-14-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/pps')
0 files changed, 0 insertions, 0 deletions