task IO accounting: improve code readability

Put all i/o statistics in struct proc_io_accounting and use inline functions to
initialize and increment statistics, removing a lot of single variable
assignments.

This also reduces the kernel size as following (with CONFIG_TASK_XACCT=y and
CONFIG_TASK_IO_ACCOUNTING=y).

    text    data     bss     dec     hex filename
   11651       0       0   11651    2d83 kernel/exit.o.before
   11619       0       0   11619    2d63 kernel/exit.o.after
   10886     132     136   11154    2b92 kernel/fork.o.before
   10758     132     136   11026    2b12 kernel/fork.o.after

 3082029  807968 4818600 8708597  84e1f5 vmlinux.o.before
 3081869  807968 4818600 8708437  84e155 vmlinux.o.after

Signed-off-by: Andrea Righi <righi.andrea@gmail.com>
Acked-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 7 insertions, 7 deletions

diff --git a/kernel/tsacct.c b/kernel/tsacct.c
index 3da47ccdc5e5..f9cd2561689c 100644
--- a/kernel/tsacct.c
+++ b/kernel/tsacct.c
@@ -94,14 +94,14 @@ void xacct_add_tsk(struct taskstats *stats, struct task_struct *p)
                 stats->hiwater_vm    = mm->hiwater_vm * PAGE_SIZE / KB;
                 mmput(mm);
         }
-        stats->read_char        = p->rchar;
-        stats->write_char       = p->wchar;
-        stats->read_syscalls    = p->syscr;
-        stats->write_syscalls   = p->syscw;
+        stats->read_char        = p->ioac.chr.rchar;
+        stats->write_char       = p->ioac.chr.wchar;
+        stats->read_syscalls    = p->ioac.chr.syscr;
+        stats->write_syscalls   = p->ioac.chr.syscw;
 #ifdef CONFIG_TASK_IO_ACCOUNTING
-        stats->read_bytes       = p->ioac.read_bytes;
-        stats->write_bytes      = p->ioac.write_bytes;
-        stats->cancelled_write_bytes = p->ioac.cancelled_write_bytes;
+        stats->read_bytes       = p->ioac.blk.read_bytes;
+        stats->write_bytes      = p->ioac.blk.write_bytes;
+        stats->cancelled_write_bytes = p->ioac.blk.cancelled_write_bytes;
 #else
         stats->read_bytes       = 0;
         stats->write_bytes      = 0;