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| author | Al Viro <viro@zeniv.linux.org.uk> | 2014-04-19 20:44:49 +0200 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2014-08-07 20:40:07 +0200 |
| commit | ecfdb33d1fbc7e6e095ba24dac2930208494e734 (patch) | |
| tree | 3e650fbb7ccc290fc4094dd420cdef3ddd966c9c /kernel/acct.c | |
| parent | Merge commit 'ccbf62d8a284cf181ac28c8e8407dd077d90dd4b' into for-next (diff) | |
| download | linux-ecfdb33d1fbc7e6e095ba24dac2930208494e734.tar.xz linux-ecfdb33d1fbc7e6e095ba24dac2930208494e734.zip | |
acct: encode_comp_t(0) is 0, fortunately...
There was an amusing bogosity in ac_rw calculation - it tried to
do encode_comp_t(encode_comp_t(0) / 1024). Seeing that comp_t is
a 3-bit exponent + 13-bit mantissa... it's a good thing that 0 is
represented by all-bits-clear.
The history of that one is interesting - it was introduced in
2.1.68pre1, when acct.c had been reworked and moved to separate
file. Two months later (2.1.86) somebody has noticed that the
sucker won't compile - there was no task_struct::io_usage.
At which point the ac_io calculation had changed from
encode_comp_t(current->io_usage) to encode_comp_t(0) and the
bug in the next line (absolutely real back then, had it ever
managed to compile) become a harmless bogosity. Looks like
nobody has ever noticed until now.
Anyway, let's bury that idiocy now that it got noticed. 17 years
is long enough...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to '')
| -rw-r--r-- | kernel/acct.c | 3 |
1 files changed, 0 insertions, 3 deletions
diff --git a/kernel/acct.c b/kernel/acct.c index a1844f14c6d6..807ebc5d8333 100644 --- a/kernel/acct.c +++ b/kernel/acct.c @@ -531,9 +531,6 @@ static void do_acct_process(struct bsd_acct_struct *acct, ac.ac_majflt = encode_comp_t(pacct->ac_majflt); ac.ac_exitcode = pacct->ac_exitcode; spin_unlock_irq(¤t->sighand->siglock); - ac.ac_io = encode_comp_t(0 /* current->io_usage */); /* %% */ - ac.ac_rw = encode_comp_t(ac.ac_io / 1024); - ac.ac_swaps = encode_comp_t(0); /* * Get freeze protection. If the fs is frozen, just skip the write |