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linux-next/drivers/lightnvm/pblk-cache.c
Javier González 6ca2f71f3e lightnvm: pblk: simplify path on REQ_PREFLUSH
On REQ_PREFLUSH, directly tag the I/O context flags to signal a flush in
the write to cache path, instead of finding the correct entry context
and imposing a memory barrier. This simplifies the code and might
potentially prevent race conditions when adding functionality to the
write path.

Signed-off-by: Javier González <javier@cnexlabs.com>
Signed-off-by: Matias Bjørling <m@bjorling.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-10-13 08:34:57 -06:00

123 lines
3.1 KiB
C

/*
* Copyright (C) 2016 CNEX Labs
* Initial release: Javier Gonzalez <javier@cnexlabs.com>
* Matias Bjorling <matias@cnexlabs.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version
* 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* pblk-cache.c - pblk's write cache
*/
#include "pblk.h"
int pblk_write_to_cache(struct pblk *pblk, struct bio *bio, unsigned long flags)
{
struct pblk_w_ctx w_ctx;
sector_t lba = pblk_get_lba(bio);
unsigned int bpos, pos;
int nr_entries = pblk_get_secs(bio);
int i, ret;
/* Update the write buffer head (mem) with the entries that we can
* write. The write in itself cannot fail, so there is no need to
* rollback from here on.
*/
retry:
ret = pblk_rb_may_write_user(&pblk->rwb, bio, nr_entries, &bpos);
switch (ret) {
case NVM_IO_REQUEUE:
io_schedule();
goto retry;
case NVM_IO_ERR:
pblk_pipeline_stop(pblk);
goto out;
}
if (unlikely(!bio_has_data(bio)))
goto out;
pblk_ppa_set_empty(&w_ctx.ppa);
w_ctx.flags = flags;
if (bio->bi_opf & REQ_PREFLUSH)
w_ctx.flags |= PBLK_FLUSH_ENTRY;
for (i = 0; i < nr_entries; i++) {
void *data = bio_data(bio);
w_ctx.lba = lba + i;
pos = pblk_rb_wrap_pos(&pblk->rwb, bpos + i);
pblk_rb_write_entry_user(&pblk->rwb, data, w_ctx, pos);
bio_advance(bio, PBLK_EXPOSED_PAGE_SIZE);
}
#ifdef CONFIG_NVM_DEBUG
atomic_long_add(nr_entries, &pblk->inflight_writes);
atomic_long_add(nr_entries, &pblk->req_writes);
#endif
pblk_rl_inserted(&pblk->rl, nr_entries);
out:
pblk_write_should_kick(pblk);
return ret;
}
/*
* On GC the incoming lbas are not necessarily sequential. Also, some of the
* lbas might not be valid entries, which are marked as empty by the GC thread
*/
int pblk_write_gc_to_cache(struct pblk *pblk, struct pblk_gc_rq *gc_rq)
{
struct pblk_w_ctx w_ctx;
unsigned int bpos, pos;
void *data = gc_rq->data;
int i, valid_entries;
/* Update the write buffer head (mem) with the entries that we can
* write. The write in itself cannot fail, so there is no need to
* rollback from here on.
*/
retry:
if (!pblk_rb_may_write_gc(&pblk->rwb, gc_rq->secs_to_gc, &bpos)) {
io_schedule();
goto retry;
}
w_ctx.flags = PBLK_IOTYPE_GC;
pblk_ppa_set_empty(&w_ctx.ppa);
for (i = 0, valid_entries = 0; i < gc_rq->nr_secs; i++) {
if (gc_rq->lba_list[i] == ADDR_EMPTY)
continue;
w_ctx.lba = gc_rq->lba_list[i];
pos = pblk_rb_wrap_pos(&pblk->rwb, bpos + valid_entries);
pblk_rb_write_entry_gc(&pblk->rwb, data, w_ctx, gc_rq->line,
gc_rq->paddr_list[i], pos);
data += PBLK_EXPOSED_PAGE_SIZE;
valid_entries++;
}
WARN_ONCE(gc_rq->secs_to_gc != valid_entries,
"pblk: inconsistent GC write\n");
#ifdef CONFIG_NVM_DEBUG
atomic_long_add(valid_entries, &pblk->inflight_writes);
atomic_long_add(valid_entries, &pblk->recov_gc_writes);
#endif
pblk_write_should_kick(pblk);
return NVM_IO_OK;
}