+
+struct cbd_backend_io {
+ struct cbd_se *se;
+ u64 off;
+ u32 len;
+ struct bio *bio;
+ struct cbd_handler *handler;
+};
+
why not use inline bvecs and avoid bio page allocation for reasonable
size ? instead of performing the allocation for each request ...
+static inline void complete_cmd(struct cbd_handler *handler, u64 priv_data, int ret)
+{
+ struct cbd_ce *ce = get_compr_head(handler);
+
+ memset(ce, 0, sizeof(*ce));
+ ce->priv_data = priv_data;
+ ce->result = ret;
+ CBDC_UPDATE_COMPR_HEAD(handler->channel_info->compr_head,
+ sizeof(struct cbd_ce),
+ handler->channel_info->compr_size);
+
+ cbdc_flush_ctrl(&handler->channel);
+
+ return;
+}
+
+static void backend_bio_end(struct bio *bio)
+{
+ struct cbd_backend_io *backend_io = bio->bi_private;
+ struct cbd_se *se = backend_io->se;
+ struct cbd_handler *handler = backend_io->handler;
+
+ if (bio->bi_status == 0 &&
+ cbd_se_hdr_get_op(se->header.len_op) == CBD_OP_READ) {
+ cbdc_copy_from_bio(&handler->channel, se->data_off, se->data_len, bio);
+ }
+
+ complete_cmd(handler, se->priv_data, bio->bi_status);
+
+ bio_free_pages(bio);
+ bio_put(bio);
+ kfree(backend_io);
+}
+
+static int cbd_bio_alloc_pages(struct bio *bio, size_t size, gfp_t gfp_mask)
+{
+ int ret = 0;
+
+ while (size) {
+ struct page *page = alloc_pages(gfp_mask, 0);
+ unsigned len = min_t(size_t, PAGE_SIZE, size);
alloc_page() call should be close to below check ..
+
+ if (!page) {
+ pr_err("failed to alloc page");
+ ret = -ENOMEM;
+ break;
+ }
+
+ ret = bio_add_page(bio, page, len, 0);
+ if (unlikely(ret != len)) {
+ __free_page(page);
+ pr_err("failed to add page");
+ break;
+ }
+
+ size -= len;
+ }
+
+ if (size)
+ bio_free_pages(bio);
+ else
+ ret = 0;
+
+ return ret;
+}
code formatting seems to be broken for above function plz check..
+
+static struct cbd_backend_io *backend_prepare_io(struct cbd_handler *handler, struct cbd_se *se, blk_opf_t opf)
+{
+ struct cbd_backend_io *backend_io;
+ struct cbd_backend *cbdb = handler->cbdb;
+
+ backend_io = kzalloc(sizeof(struct cbd_backend_io), GFP_KERNEL);
will above allocation always succeed ? or NULL check should be here ?
+ backend_io->se = se;
+
+ backend_io->handler = handler;
+ backend_io->bio = bio_alloc_bioset(cbdb->bdev, roundup(se->len, 4096) / 4096, opf, GFP_KERNEL, &handler->bioset);
+
+ backend_io->bio->bi_iter.bi_sector = se->offset >> SECTOR_SHIFT;
+ backend_io->bio->bi_iter.bi_size = 0;
+ backend_io->bio->bi_private = backend_io;
+ backend_io->bio->bi_end_io = backend_bio_end;
+
+ return backend_io;
+}
+
+static int handle_backend_cmd(struct cbd_handler *handler, struct cbd_se *se)
+{
+ struct cbd_backend *cbdb = handler->cbdb;
+ u32 len = se->len;
+ struct cbd_backend_io *backend_io = NULL;
+ int ret;
+
+ if (cbd_se_hdr_flags_test(se, CBD_SE_HDR_DONE)) {
+ return 0 ;
+ }
+
+ switch (cbd_se_hdr_get_op(se->header.len_op)) {
+ case CBD_OP_PAD:
+ cbd_se_hdr_flags_set(se, CBD_SE_HDR_DONE);
+ return 0;
+ case CBD_OP_READ:
+ backend_io = backend_prepare_io(handler, se, REQ_OP_READ);
+ break;
+ case CBD_OP_WRITE:
+ backend_io = backend_prepare_io(handler, se, REQ_OP_WRITE);
+ break;
+ case CBD_OP_DISCARD:
+ ret = blkdev_issue_discard(cbdb->bdev, se->offset >> SECTOR_SHIFT,
+ se->len, GFP_NOIO);
any specific reason to not use GFP_KERNEL ?
+ goto complete_cmd;
+ case CBD_OP_WRITE_ZEROS:
+ ret = blkdev_issue_zeroout(cbdb->bdev, se->offset >> SECTOR_SHIFT,
+ se->len, GFP_NOIO, 0);
any specific reason to not use GFP_KERNEL ?
+ goto complete_cmd;
+ case CBD_OP_FLUSH:
+ ret = blkdev_issue_flush(cbdb->bdev);
+ goto complete_cmd;
+ default:
+ pr_err("unrecognized op: %x", cbd_se_hdr_get_op(se->header.len_op));
+ ret = -EIO;
+ goto complete_cmd;
+ }
+
+ if (!backend_io)
+ return -ENOMEM;
there is no NULL check in the backend_prepare_io() not sure about
above condition in current code unless you return NULL ...
+
+ ret = cbd_bio_alloc_pages(backend_io->bio, len, GFP_NOIO);
+ if (ret) {
+ kfree(backend_io);
+ return ret;
+ }
+
+ if (cbd_se_hdr_get_op(se->header.len_op) == CBD_OP_WRITE) {
+ cbdc_copy_to_bio(&handler->channel, se->data_off, se->data_len, backend_io->bio);
+ }
+
+ submit_bio(backend_io->bio);
+
unless I didn't understand the code, you are building a single bio from
incoming request, that might not have enough space to accommodate all
the data from incoming request, hence you are returning an error from
cbd_bio_alloc_pages() when bio_add_page() fail ...
bio_add_page() can fail for multiple reasons, instead of trying to
build only one bio that might be smaller for the size of the I/O and
returning error, why not use the chain of the small size bios ? that
way you will not run out of the space in single bio and still finish
the I/O by avoiding bio_add_page() failure that might happen due to
bio full ?
+ return 0;
+
+complete_cmd:
+ complete_cmd(handler, se->priv_data, ret);
+ return 0;
+}
+
+static void handle_work_fn(struct work_struct *work)
+{
+ struct cbd_handler *handler = container_of(work, struct cbd_handler, handle_work.work);
+ struct cbd_se *se;
+ int ret;
+again:
+ /* channel ctrl would be updated by blkdev queue */
+ cbdc_flush_ctrl(&handler->channel);
+ se = get_se_to_handle(handler);
+ if (se == get_se_head(handler)) {
+ if (cbdwc_need_retry(&handler->handle_worker_cfg)) {
+ goto again;
+ }
+
+ cbdwc_miss(&handler->handle_worker_cfg);
+
+ queue_delayed_work(handler->handle_wq, &handler->handle_work, usecs_to_jiffies(0));
+ return;
+ }
+
+ cbdwc_hit(&handler->handle_worker_cfg);
+ cbdt_flush_range(handler->cbdb->cbdt, se, sizeof(*se));
+ ret = handle_backend_cmd(handler, se);
+ if (!ret) {
+ /* this se is handled */
+ handler->se_to_handle = (handler->se_to_handle + cbd_se_hdr_get_len(se->header.len_op)) % handler->channel_info->cmdr_size;
this is a really long line, if possible keep code under 80 char, I know
it's not a requirement anymore but it will match block drivers ..
-ck