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ore: Remove redundant dev_order(), more cleanups 

Two cleanups:
* si->cur_comp, si->cur_pg where always calculated after
  the call to ore_calc_stripe_info() with the help of
  _dev_order(...). But these are already calculated by
  ore_calc_stripe_info() and can be just set there.
  (This is left over from the time that si->cur_comp, si->cur_pg
   were only used by raid code, but now the main loop manages
   them anyway even though they are ultimately not used in
   none raid code)

* si->cur_comp - For the very last stripe case, was set inside
  _ore_add_parity_unit(). This is not clear and will be wrong
  for coming raid6 so move this to only caller. Now si->cur_comp
  is only manipulated within _prepare_for_striping(), always next
  to the manipulation of cur_dev.
  Which is much easier to understand and follow.

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
This commit is contained in:
Boaz Harrosh 2014-04-09 23:14:38 +03:00
parent 101a642781
commit 455682ce54
3 changed files with 10 additions and 31 deletions
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10
fs/exofs/ore.c
View File

@ -545,17 +545,19 @@ void ore_calc_stripe_info(struct ore_layout *layout, u64 file_offset,
/* "H - (N * U)" is just "H % U" so it's bound to u32 */
u32 C = (u32)(H - (N * U)) / stripe_unit + G * group_width;
u32 first_dev = C - C % group_width;
div_u64_rem(file_offset, stripe_unit, &si->unit_off);
si->obj_offset = si->unit_off + (N * stripe_unit) +
(M * group_depth * stripe_unit);
si->cur_comp = C - first_dev;
si->cur_pg = si->unit_off / PAGE_SIZE;
if (parity) {
u32 LCMdP = lcm(group_width, parity) / parity;
/* R = N % LCMdP; */
u32 RxP = (N % LCMdP) * parity;
u32 first_dev = C - C % group_width;
si->par_dev = (group_width + group_width - parity - RxP) %
group_width + first_dev;
@ -670,9 +672,7 @@ static int _prepare_for_striping(struct ore_io_state *ios)
BUG_ON(length > si->length);
dev_order = _dev_order(devs_in_group, mirrors_p1, si->par_dev, dev);
si->cur_comp = dev_order;
si->cur_pg = si->unit_off / PAGE_SIZE;
dev_order = si->cur_comp;
while (length) {
struct ore_per_dev_state *per_dev =
@ -718,6 +718,8 @@ static int _prepare_for_striping(struct ore_io_state *ios)
* stripe. then operate on parity dev.
*/
dev = si->par_dev;
/* If last stripe operate on parity comp */
si->cur_comp = group_width - ios->layout->parity;
}
per_dev = &ios->per_dev[dev - first_dev];
if (!per_dev->length) {

13
fs/exofs/ore_raid.c
View File

@ -402,9 +402,8 @@ static int _add_to_r4w_last_page(struct ore_io_state *ios, u64 *offset)
ore_calc_stripe_info(ios->layout, *offset, 0, &si);
p = si.unit_off / PAGE_SIZE;
c = _dev_order(ios->layout->group_width * ios->layout->mirrors_p1,
ios->layout->mirrors_p1, si.par_dev, si.dev);
p = si.cur_pg;
c = si.cur_comp;
page = ios->sp2d->_1p_stripes[p].pages[c];
pg_len = PAGE_SIZE - (si.unit_off % PAGE_SIZE);
@ -532,9 +531,8 @@ static int _read_4_write_last_stripe(struct ore_io_state *ios)
goto read_it;
ore_calc_stripe_info(ios->layout, offset, 0, &read_si);
p = read_si.unit_off / PAGE_SIZE;
c = _dev_order(ios->layout->group_width * ios->layout->mirrors_p1,
ios->layout->mirrors_p1, read_si.par_dev, read_si.dev);
p = read_si.cur_pg;
c = read_si.cur_comp;
if (min_p == sp2d->pages_in_unit) {
/* Didn't do it yet */
@ -638,9 +636,6 @@ int _ore_add_parity_unit(struct ore_io_state *ios,
si->cur_pg = _sp2d_min_pg(sp2d);
num_pages = _sp2d_max_pg(sp2d) + 1 - si->cur_pg;
if (!cur_len) /* If last stripe operate on parity comp */
si->cur_comp = sp2d->data_devs;
if (!per_dev->length) {
per_dev->offset += si->cur_pg * PAGE_SIZE;
/* If first stripe, Read in all read4write pages

18
fs/exofs/ore_raid.h
View File

@ -31,24 +31,6 @@
#define ORE_DBGMSG2(M...) do {} while (0)
/* #define ORE_DBGMSG2 ORE_DBGMSG */
/* Calculate the component order in a stripe. eg the logical data unit
* address within the stripe of @dev given the @par_dev of this stripe.
*/
static inline unsigned _dev_order(unsigned devs_in_group, unsigned mirrors_p1,
unsigned par_dev, unsigned dev)
{
unsigned first_dev = dev - dev % devs_in_group;
dev -= first_dev;
par_dev -= first_dev;
if (devs_in_group == par_dev) /* The raid 0 case */
return dev / mirrors_p1;
/* raid4/5/6 case */
return ((devs_in_group + dev - par_dev - mirrors_p1) % devs_in_group) /
mirrors_p1;
}
/* ios_raid.c stuff needed by ios.c */
int _ore_post_alloc_raid_stuff(struct ore_io_state *ios);
void _ore_free_raid_stuff(struct ore_io_state *ios);