/*
* WRITE case:
*
* sbl is the list of bio; the first bio in the list and iblk specify
* destination file offset; the content of bios in sbl is scattered source
* buffer.
*
* The goal is to write source buffer to the file with given offset. We're
* doing it by stuffing as many bvecs from source to kreqs as possible and
* submitting kreqs to in-kernel aio.
*
* READ case:
*
* The same as WRITE, but here the file plays the role of source and the
* content of bios in sbl plays the role of destination.
*/
static void kaio_sbl_submit(struct file *file, struct ploop_request *preq,
unsigned long rw, struct bio_list *sbl,
iblock_t iblk, size_t size)
{
struct bio *bio = sbl->head;
int idx = 0;
loff_t off = bio->bi_sector;
off = ((loff_t)iblk << preq->plo->cluster_log) |
(off & ((1<<preq->plo->cluster_log) - 1));
if (rw & REQ_WRITE)
ploop_prepare_tracker(preq, off);
off <<= 9;
/* since now 'off' always points to a position in the file to X-mit */
WARN_ONCE(!(file->f_flags & O_DIRECT), "File opened w/o O_DIRECT");
ploop_prepare_io_request(preq);
size <<= 9;
while (size > 0) {
struct kaio_req *kreq;
int nr_segs;
size_t copy;
int err;
kreq = kaio_kreq_alloc(preq, &nr_segs);
if (!kreq) {
PLOOP_REQ_SET_ERROR(preq, -ENOMEM);
break;
}
copy = kaio_kreq_pack(kreq, &nr_segs, &bio, &idx, size);
atomic_inc(&preq->io_count);
err = kaio_kernel_submit(file, kreq, nr_segs, copy, off, rw);
if (err) {
PLOOP_REQ_SET_ERROR(preq, err);
ploop_complete_io_request(preq);
kfree(kreq);
break;
}
off += copy;
size -= copy;
}
kaio_complete_io_request(preq);
}
static void
kaio_submit(struct ploop_io *io, struct ploop_request * preq,
unsigned long rw,
struct bio_list *sbl, iblock_t iblk, unsigned int size)
{
struct bio * b;
if (rw & BIO_FLUSH) {
spin_lock_irq(&io->plo->lock);
kaio_queue_fsync_req(preq);
io->plo->st.bio_syncwait++;
spin_unlock_irq(&io->plo->lock);
return;
}
ploop_prepare_io_request(preq);
if (iblk == PLOOP_ZERO_INDEX)
iblk = 0;
if (rw & (1<<BIO_RW)) {
loff_t off = sbl->head->bi_sector;
off = ((loff_t)iblk << preq->plo->cluster_log) |
(off & ((1<<preq->plo->cluster_log) - 1));
ploop_prepare_tracker(preq, off);
}
for (b = sbl->head; b != NULL; b = b->bi_next) {
int err;
atomic_inc(&preq->io_count);
err = kaio_kernel_submit(io->files.file, b, preq, iblk, rw);
if (err) {
ploop_set_error(preq, err);
ploop_complete_io_request(preq);
break;
}
}
kaio_complete_io_request(preq);
}