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copy: convert state lvalues to references

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Thomas Schoebel-Theuer 2022-02-22 05:41:03 +01:00 committed by Thomas Schoebel-Theuer
parent 976857a9d7
commit 44f371ca7f
1 changed files with 25 additions and 8 deletions
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33
kernel/mars_copy.c
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@ -52,6 +52,22 @@
#define GET_STATE(brick,index) \
((brick)->st[(__u64)(index) / STATES_PER_PAGE][(__u64)(index) % STATES_PER_PAGE])
/* Hint: MARS prefers safety, not maximum performance.
* For safety against compiler mischief, we use *_ONCE() on state fields
* (almost anywhere), at least for now.
* For example, ->len might be shortened by short reads etc, and this might
* might be driven by interrupts or similar frequencies.
* Full SMP memory barriers are currently not (yet) in scope, because the
* ordinary SMP delays / bottlenecks _should_ not make harm.
* Therefore, we try to avoid smp_*() for now (except low-frequency
* initializations & co).
*
* Note: _GET_STATE() should be equivalent to pure address calculations, but
* no relevant memory deref to high-frequency updated mem.
*/
#define _GET_STATE(brick,index) \
(&GET_STATE(brick,index))
///////////////////////// own type definitions ////////////////////////
#include "mars_copy.h"
@ -158,7 +174,7 @@ void __clear_mref(struct copy_brick *brick, struct mref_object *mref, unsigned q
static
void _clear_mref(struct copy_brick *brick, unsigned index, unsigned queue)
{
struct copy_state *st = &GET_STATE(brick, index);
struct copy_state *st = _GET_STATE(brick, index);
struct mref_object *mref = READ_ONCE(st->table[queue]);
if (mref) {
@ -179,7 +195,8 @@ void _clear_all_mref(struct copy_brick *brick)
unsigned i;
for (i = 0; i < NR_COPY_REQUESTS; i++) {
struct copy_state *st = &GET_STATE(brick, i);
struct copy_state *st = _GET_STATE(brick, i);
st->state = COPY_STATE_START;
_clear_mref(brick, i, 0);
_clear_mref(brick, i, 1);
@ -267,7 +284,7 @@ void copy_endio(struct generic_callback *cb)
}
#endif
st = &GET_STATE(brick, index);
st = _GET_STATE(brick, index);
MARS_IO("queue=%u index=%u pos=%lld state=%d err=%d\n",
queue, index,
@ -375,7 +392,7 @@ int _make_mref(struct copy_brick *brick,
}
/* Check the state table */
st = &GET_STATE(brick, index);
st = _GET_STATE(brick, index);
old_mref = READ_ONCE(st->table[queue]);
if (unlikely(old_mref)) {
MARS_ERR("cannot override old_mref=%p at index=%u queue=%d pos=%lld+%lld flags=%d\n",
@ -534,7 +551,7 @@ int _next_state(struct copy_brick *brick, unsigned index, loff_t pos,
int progress = 0;
int status;
st = &GET_STATE(brick, index);
st = _GET_STATE(brick, index);
next_state = st->state;
restart:
@ -747,7 +764,7 @@ restart:
unsigned prev_index = (index + (wrap - 1)) % wrap;
struct copy_state *prev_st;
prev_st = &GET_STATE(brick, prev_index);
prev_st = _GET_STATE(brick, prev_index);
if (!READ_ONCE(prev_st->writeout))
goto idle;
}
@ -915,7 +932,7 @@ int _run_copy(struct copy_brick *brick, loff_t this_start)
pos < brick->copy_last + MAX_ACTIVE_AREA;
pos = ((pos / COPY_CHUNK) + 1) * COPY_CHUNK) {
unsigned index = GET_INDEX(pos);
struct copy_state *st = &GET_STATE(brick, index);
struct copy_state *st = _GET_STATE(brick, index);
int this_progress;
if (max-- <= 0) {
@ -947,7 +964,7 @@ int _run_copy(struct copy_brick *brick, loff_t this_start)
pos = ((pos / COPY_CHUNK) + 1) * COPY_CHUNK) {
unsigned len;
unsigned index = GET_INDEX(pos);
struct copy_state *st = &GET_STATE(brick, index);
struct copy_state *st = _GET_STATE(brick, index);
bool is_active;
if (st->state != COPY_STATE_FINISHED) {