mirror of https://github.com/schoebel/mars
1038 lines
26 KiB
C
1038 lines
26 KiB
C
// (c) 2010 Thomas Schoebel-Theuer / 1&1 Internet AG
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// Buf brick
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//#define BRICK_DEBUGGING
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//#define MARS_DEBUGGING
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/string.h>
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#include <linux/bio.h>
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#include <linux/blkdev.h>
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#include <linux/delay.h>
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#include "mars.h"
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///////////////////////// own type definitions ////////////////////////
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#include "mars_buf.h"
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#define PRE_ALLOC 8
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///////////////////////// own helper functions ////////////////////////
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static inline int buf_hash(struct buf_brick *brick, unsigned int base_index)
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{
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return base_index % MARS_BUF_HASH_MAX;
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}
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static struct buf_head *hash_find(struct buf_brick *brick, unsigned int base_index)
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{
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int hash = buf_hash(brick, base_index);
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struct list_head *start = &brick->cache_anchors[hash];
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struct list_head *tmp;
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struct buf_head *res;
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for (tmp = start->next; ; tmp = tmp->next) {
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if (tmp == start)
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return NULL;
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res = container_of(tmp, struct buf_head, bf_hash_head);
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if (res->bf_base_index == base_index)
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break;
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}
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return res;
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}
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static inline void hash_insert(struct buf_brick *brick, struct buf_head *elem)
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{
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int hash = buf_hash(brick, elem->bf_base_index);
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struct list_head *start = &brick->cache_anchors[hash];
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list_add(&elem->bf_hash_head, start);
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}
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static inline void free_buf(struct buf_brick *brick, struct buf_head *bf)
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{
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free_pages((unsigned long)bf->bf_data, brick->backing_order);
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kfree(bf);
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}
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/* brick->brick_lock must be held
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*/
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static inline void __prune_cache(struct buf_brick *brick, int max_count, unsigned long *flags)
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{
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#if 0
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return;
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#endif
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while (brick->alloc_count >= max_count) {
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struct buf_head *bf;
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if (list_empty(&brick->free_anchor))
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break;
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bf = container_of(brick->free_anchor.next, struct buf_head, bf_lru_head);
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list_del_init(&bf->bf_lru_head);
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brick->alloc_count--;
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traced_unlock(&brick->brick_lock, *flags);
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free_buf(brick, bf);
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traced_lock(&brick->brick_lock, *flags);
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}
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}
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static inline void __lru_free_one(struct buf_brick *brick)
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{
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struct buf_head *bf;
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if (list_empty(&brick->lru_anchor))
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return;
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bf = container_of(brick->lru_anchor.prev, struct buf_head, bf_lru_head);
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list_del_init(&bf->bf_lru_head);
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list_del_init(&bf->bf_hash_head);
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brick->hashed_count--;
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#if 1
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if (unlikely(
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!list_empty(&bf->bf_io_pending_anchor) ||
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!list_empty(&bf->bf_again_write_pending_anchor)
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)) {
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MARS_ERR("freed bf is member in lists!\n");
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}
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#endif
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list_add(&bf->bf_lru_head, &brick->free_anchor);
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}
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static inline void __lru_free(struct buf_brick *brick)
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{
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while (brick->hashed_count >= brick->max_count) {
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if (list_empty(&brick->lru_anchor))
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break;
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__lru_free_one(brick);
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}
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}
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static inline int get_info(struct buf_brick *brick)
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{
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struct buf_input *input = brick->inputs[0];
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int status = GENERIC_INPUT_CALL(input, mars_get_info, &brick->base_info);
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if (status >= 0) {
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brick->got_info = 1;
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}
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return status;
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}
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/* Convert from arbitrary/odd kernel address/length to struct page,
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* create bio from it, round up/down to full sectors.
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* return the length (may be smaller or even larger than requested)
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*/
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static int make_bio(struct buf_brick *brick, struct bio **_bio, void *data, loff_t pos, int len)
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{
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unsigned long long sector;
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int sector_offset;
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int page_offset;
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int page_len;
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int bvec_count;
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int status;
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int i;
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struct page *page;
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struct bio *bio = NULL;
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struct block_device *bdev;
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if (unlikely(!brick->got_info)) {
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struct request_queue *q;
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status = get_info(brick);
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if (status < 0)
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goto out;
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bdev = brick->base_info.backing_file->f_mapping->host->i_sb->s_bdev;
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q = bdev_get_queue(bdev);
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brick->bvec_max = queue_max_hw_sectors(q) >> (PAGE_SHIFT - 9);
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} else {
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bdev = brick->base_info.backing_file->f_mapping->host->i_sb->s_bdev;
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}
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if (unlikely(len <= 0)) {
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MARS_ERR("bad bio len %d\n", len);
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status = -EINVAL;
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goto out;
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}
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sector = pos >> 9; // TODO: make dynamic
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sector_offset = pos & ((1 << 9) - 1); // TODO: make dynamic
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// round down to start of first sector
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data -= sector_offset;
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len += sector_offset;
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pos -= sector_offset;
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// round up to full sector
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len = (((len - 1) >> 9) + 1) << 9; // TODO: make dynamic
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// map onto pages. TODO: allow higher-order pages (performance!)
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page_offset = pos & (PAGE_SIZE - 1);
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page_len = len + page_offset;
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bvec_count = (page_len - 1) / PAGE_SIZE + 1;
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if (bvec_count > brick->bvec_max)
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bvec_count = brick->bvec_max;
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bio = bio_alloc(GFP_MARS, bvec_count);
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status = -ENOMEM;
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if (!bio)
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goto out;
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status = 0;
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for (i = 0; i < bvec_count && len > 0; i++) {
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int myrest = PAGE_SIZE - page_offset;
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int mylen = len;
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if (mylen > myrest)
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mylen = myrest;
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page = virt_to_page(data);
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bio->bi_io_vec[i].bv_page = page;
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bio->bi_io_vec[i].bv_len = mylen;
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bio->bi_io_vec[i].bv_offset = page_offset;
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data += mylen;
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len -= mylen;
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status += mylen;
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page_offset = 0;
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}
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if (unlikely(len)) {
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bio_put(bio);
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bio = NULL;
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MARS_ERR("computation of bvec_count %d was wrong, diff=%d\n", bvec_count, len);
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status = -EIO;
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goto out;
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}
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bio->bi_vcnt = i;
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bio->bi_idx = 0;
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bio->bi_size = status;
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bio->bi_sector = sector;
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bio->bi_bdev = bdev;
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bio->bi_private = NULL; // must be filled in later
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bio->bi_end_io = NULL; // must be filled in later
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bio->bi_rw = 0; // must be filled in later
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// ignore rounding-down on return
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if (status >= sector_offset)
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status -= sector_offset;
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out:
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*_bio = bio;
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return status;
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}
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static inline struct buf_head *_alloc_bf(struct buf_brick *brick)
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{
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struct buf_head *bf = kzalloc(sizeof(struct buf_head), GFP_MARS);
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if (!bf)
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goto done;
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bf->bf_data = (void*)__get_free_pages(GFP_MARS, brick->backing_order);
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if (unlikely(!bf->bf_data)) {
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kfree(bf);
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bf = NULL;
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}
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done:
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return bf;
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}
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static void __pre_alloc_bf(struct buf_brick *brick, int max)
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{
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while (max-- > 0) {
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struct buf_head *bf = _alloc_bf(brick);
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unsigned long flags;
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if (unlikely(!bf))
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break;
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traced_lock(&brick->brick_lock, flags);
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list_add(&bf->bf_lru_head, &brick->free_anchor);
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brick->alloc_count++;
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traced_unlock(&brick->brick_lock, flags);
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}
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}
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////////////////// own brick / input / output operations //////////////////
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static int buf_get_info(struct buf_output *output, struct mars_info *info)
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{
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struct buf_input *input = output->brick->inputs[0];
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return GENERIC_INPUT_CALL(input, mars_get_info, info);
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}
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static int buf_ref_get(struct buf_output *output, struct mars_ref_object *mref)
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{
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struct buf_brick *brick = output->brick;
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struct buf_mars_ref_aspect *mref_a;
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struct buf_head *bf;
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loff_t base_pos;
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int base_offset;
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int max_len;
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unsigned long flags;
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int status = -EILSEQ;
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might_sleep();
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if (unlikely(mref->orig_bio)) {
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MARS_ERR("illegal: mref has a bio assigend\n");
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}
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#ifdef PRE_ALLOC
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if (unlikely(brick->alloc_count < brick->max_count)) {
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// grab all memory in one go => avoid memory fragmentation
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__pre_alloc_bf(brick, brick->max_count + PRE_ALLOC - brick->alloc_count);
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}
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#endif
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/* Grab reference.
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*/
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_CHECK_SPIN(&mref->ref_count, !=, 0);
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atomic_inc(&mref->ref_count);
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mref_a = buf_mars_ref_get_aspect(output, mref);
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if (unlikely(!mref_a))
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goto done;
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base_pos = mref->ref_pos & ~(loff_t)(brick->backing_size - 1);
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base_offset = (mref->ref_pos - base_pos);
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if (unlikely(base_offset < 0 || base_offset >= brick->backing_size)) {
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MARS_ERR("bad base_offset %d\n", base_offset);
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}
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max_len = brick->backing_size - base_offset;
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if (mref->ref_len > max_len)
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mref->ref_len = max_len;
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traced_lock(&brick->brick_lock, flags);
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again:
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bf = hash_find(brick, ((unsigned int)base_pos) >> brick->backing_order);
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if (bf) {
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atomic_inc(&brick->hit_count);
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list_del_init(&bf->bf_lru_head);
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CHECK_SPIN(&bf->bf_count, 0);
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atomic_inc(&bf->bf_count);
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} else {
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MARS_DBG("buf_get() hash nothing found\n");
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if (list_empty(&brick->free_anchor)) {
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__lru_free_one(brick);
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if (unlikely(list_empty(&brick->free_anchor))) {
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MARS_INF("alloc new buf_head %d\n", brick->alloc_count);
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traced_unlock(&brick->brick_lock, flags);
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status = -ENOMEM;
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bf = _alloc_bf(brick);
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if (!bf)
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goto done;
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traced_lock(&brick->brick_lock, flags);
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list_add(&bf->bf_lru_head, &brick->free_anchor);
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brick->alloc_count++;
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/* during the open lock, somebody might have raced
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* against us at the same base_pos...
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*/
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goto again;
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}
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}
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atomic_inc(&brick->miss_count);
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bf = container_of(brick->free_anchor.next, struct buf_head, bf_lru_head);
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list_del_init(&bf->bf_lru_head);
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MARS_DBG("buf_get() bf=%p\n", bf);
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bf->bf_brick = brick;
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bf->bf_pos = base_pos;
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bf->bf_base_index = ((unsigned int)base_pos) >> brick->backing_order;
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bf->bf_flags = 0;
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atomic_set(&bf->bf_count, 1);
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bf->bf_bio_status = 0;
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atomic_set(&bf->bf_bio_count, 0);
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//INIT_LIST_HEAD(&bf->bf_mref_anchor);
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//INIT_LIST_HEAD(&bf->bf_lru_head);
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INIT_LIST_HEAD(&bf->bf_hash_head);
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INIT_LIST_HEAD(&bf->bf_io_pending_anchor);
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INIT_LIST_HEAD(&bf->bf_again_write_pending_anchor);
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hash_insert(brick, bf);
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brick->hashed_count++;
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}
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mref_a->bfa_bf = bf;
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MARS_DBG("bf=%p initial bf_count=%d\n", bf, atomic_read(&bf->bf_count));
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mref->ref_flags = bf->bf_flags;
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traced_unlock(&brick->brick_lock, flags);
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mref->ref_data = bf->bf_data + base_offset;
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CHECK_SPIN(&mref->ref_count, 1);
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return mref->ref_len;
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done:
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return status;
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}
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//#define FAST
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static void __bf_put(struct buf_head *bf)
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{
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struct buf_brick *brick;
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int bf_count;
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unsigned long flags;
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MARS_DBG("bf=%p bf_count=%d\n", bf, bf_count);
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CHECK_SPIN(&bf->bf_count, 1);
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#ifdef FAST
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if (!atomic_dec_and_test(&bf->bf_count))
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return;
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MARS_DBG("ZERO_COUNT\n");
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#endif
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brick = bf->bf_brick;
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traced_lock(&brick->brick_lock, flags);
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#ifdef FAST
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/* NOTE: this may race against the above atomic_dec_and_test().
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* But in worst case, nothing happens.
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* So this race is ok.
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*/
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bf_count = atomic_read(&bf->bf_count);
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#else
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if (!atomic_dec_and_test(&bf->bf_count)) {
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traced_unlock(&brick->brick_lock, flags);
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return;
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}
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MARS_DBG("ZERO_COUNT\n");
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bf_count = 0;
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#endif
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if (likely(bf_count <= 0)) {
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if (unlikely(bf_count < 0)) {
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atomic_set(&bf->bf_count, 0);
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MARS_ERR("bf_count UNDERRUN %d\n", bf_count);
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}
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#if 1
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if (unlikely(!list_empty(&bf->bf_io_pending_anchor))) {
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MARS_ERR("bf_io_pending_anchor is not empty!\n");
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}
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if (unlikely(!list_empty(&bf->bf_again_write_pending_anchor))) {
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MARS_ERR("bf_again_write_pending_anchor is not empty!\n");
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}
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#endif
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list_del(&bf->bf_lru_head);
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if (likely(bf->bf_flags & MARS_REF_UPTODATE)) {
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list_add(&bf->bf_lru_head, &brick->lru_anchor);
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} else {
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list_add_tail(&bf->bf_lru_head, &brick->lru_anchor);
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}
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} // else no harm can happen
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// lru freeing (this is completeley independent from bf)
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__lru_free(brick);
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__prune_cache(brick, brick->max_count * 2, &flags);
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traced_unlock(&brick->brick_lock, flags);
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}
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static void _buf_ref_put(struct buf_mars_ref_aspect *mref_a)
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{
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struct mars_ref_object *mref = mref_a->object;
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struct buf_head *bf;
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CHECK_SPIN(&mref->ref_count, 1);
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if (!atomic_dec_and_test(&mref->ref_count))
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return;
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bf = mref_a->bfa_bf;
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if (bf) {
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MARS_DBG("buf_ref_put() mref=%p mref_a=%p bf=%p\n", mref, mref_a, bf);
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__bf_put(bf);
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}
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buf_free_mars_ref(mref);
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}
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static void buf_ref_put(struct buf_output *output, struct mars_ref_object *mref)
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{
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struct buf_mars_ref_aspect *mref_a;
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mref_a = buf_mars_ref_get_aspect(output, mref);
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if (unlikely(!mref_a)) {
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MARS_FAT("cannot get aspect\n");
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return;
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}
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_buf_ref_put(mref_a);
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}
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static void _buf_endio(struct mars_ref_object *mref)
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{
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int error = mref->cb_error;
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struct bio *bio = mref->orig_bio;
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MARS_DBG("_buf_endio() mref=%p bio=%p\n", mref, bio);
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if (bio) {
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if (error < 0) {
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MARS_ERR("_buf_endio() error=%d bi_size=%d\n", error, bio->bi_size);
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}
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if (error > 0)
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error = 0;
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bio_endio(bio, error);
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bio_put(bio);
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} else {
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//...
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}
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}
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static void _buf_bio_callback(struct bio *bio, int code);
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static int _buf_make_bios(struct buf_brick *brick, struct buf_head *bf, void *start_data, loff_t start_pos, int start_len, int rw)
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{
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struct buf_input *input;
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LIST_HEAD(tmp);
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int status = EINVAL;
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int iters = 0;
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#if 1
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loff_t bf_end = bf->bf_pos + brick->backing_size;
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loff_t end_pos;
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if (start_pos < bf->bf_pos || start_pos >= bf_end) {
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MARS_ERR("bad start_pos %llu (%llu ... %llu)\n", start_pos, bf->bf_pos, bf_end);
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goto done;
|
|
}
|
|
end_pos = start_pos + start_len;
|
|
if (end_pos <= bf->bf_pos || end_pos > bf_end) {
|
|
MARS_ERR("bad end_pos %llu (%llu ... %llu)\n", end_pos, bf->bf_pos, bf_end);
|
|
goto done;
|
|
}
|
|
if (!start_data) {
|
|
MARS_ERR("bad start_data\n");
|
|
goto done;
|
|
}
|
|
if (start_len <= 0) {
|
|
MARS_ERR("bad start_len %d\n", start_len);
|
|
goto done;
|
|
}
|
|
#endif
|
|
status = -ENOMEM;
|
|
while (start_len > 0) {
|
|
struct mars_ref_object *mref;
|
|
struct buf_mars_ref_aspect *mref_a;
|
|
struct bio *bio = NULL;
|
|
int len;
|
|
|
|
mref = buf_alloc_mars_ref(brick->outputs[0], &brick->mref_object_layout);
|
|
if (unlikely(!mref))
|
|
break;
|
|
|
|
mref_a = buf_mars_ref_get_aspect(brick->outputs[0], mref);
|
|
if (unlikely(!mref_a)) {
|
|
buf_free_mars_ref(mref);
|
|
break;
|
|
}
|
|
|
|
list_add(&mref_a->tmp_head, &tmp);
|
|
mref_a->bfa_bf = bf;
|
|
|
|
len = make_bio(brick, &bio, start_data, start_pos, start_len);
|
|
if (unlikely(len <= 0 || !bio)) {
|
|
buf_free_mars_ref(mref);
|
|
break;
|
|
}
|
|
|
|
bio->bi_private = mref_a;
|
|
bio->bi_end_io = _buf_bio_callback;
|
|
bio->bi_rw = rw;
|
|
mref->cb_ref_endio = _buf_endio;
|
|
|
|
mars_ref_attach_bio(mref, bio);
|
|
|
|
start_data += len;
|
|
start_pos += len;
|
|
start_len -= len;
|
|
iters++;
|
|
}
|
|
if (!start_len)
|
|
status = 0;
|
|
#if 1
|
|
if (iters != 1) {
|
|
MARS_INF("start_pos=%lld start_len=%d iters=%d, status=%d\n", start_pos, start_len, iters, status);
|
|
}
|
|
iters = 0;
|
|
#endif
|
|
|
|
input = brick->inputs[0];
|
|
while (!list_empty(&tmp)) {
|
|
struct mars_ref_object *mref;
|
|
struct buf_mars_ref_aspect *mref_a;
|
|
mref_a = container_of(tmp.next, struct buf_mars_ref_aspect, tmp_head);
|
|
mref = mref_a->object;
|
|
list_del_init(&mref_a->tmp_head);
|
|
iters++;
|
|
|
|
if (status < 0) { // clean up
|
|
mref->cb_error = status;
|
|
mref->cb_ref_endio(mref);
|
|
#if 0
|
|
if (mref->orig_bio)
|
|
bio_put(mref->orig_bio);
|
|
#endif
|
|
buf_free_mars_ref(mref);
|
|
continue;
|
|
}
|
|
|
|
/* Remember the number of bios we are submitting.
|
|
*/
|
|
CHECK_SPIN(&bf->bf_bio_count, 0);
|
|
atomic_inc(&bf->bf_bio_count);
|
|
|
|
MARS_DBG("starting buf IO mref=%p bio=%p bf=%p bf_count=%d bf_bio_count=%d\n", mref, mref->orig_bio, bf, atomic_read(&bf->bf_count), atomic_read(&bf->bf_bio_count));
|
|
#if 1
|
|
GENERIC_INPUT_CALL(input, mars_ref_io, mref, rw);
|
|
#else
|
|
// fake IO for testing
|
|
mref->cb_error = status;
|
|
mref->cb_ref_endio(mref);
|
|
#if 0
|
|
if (mref->orig_bio)
|
|
bio_put(mref->orig_bio);
|
|
#endif
|
|
buf_free_mars_buf(mref);
|
|
#endif
|
|
}
|
|
#if 1
|
|
if (iters != 1) {
|
|
MARS_INF("start_pos=%lld start_len=%d iters=%d, status=%d\n", start_pos, start_len, iters, status);
|
|
}
|
|
iters = 0;
|
|
#endif
|
|
done:
|
|
return status;
|
|
}
|
|
|
|
/* This is called from the bio layer.
|
|
*/
|
|
static void _buf_bio_callback(struct bio *bio, int code)
|
|
{
|
|
struct buf_mars_ref_aspect *mref_a;
|
|
struct buf_head *bf;
|
|
struct buf_brick *brick;
|
|
void *start_data = NULL;
|
|
loff_t start_pos = 0;
|
|
int start_len = 0;
|
|
int old_flags;
|
|
unsigned long flags;
|
|
LIST_HEAD(tmp);
|
|
#if 1
|
|
int count = 0;
|
|
#endif
|
|
|
|
mref_a = bio->bi_private;
|
|
bf = mref_a->bfa_bf;
|
|
|
|
MARS_DBG("_buf_bio_callback() mref=%p bio=%p bf=%p bf_count=%d bf_bio_count=%d code=%d\n", mref_a->object, bio, bf, atomic_read(&bf->bf_count), atomic_read(&bf->bf_bio_count), code);
|
|
|
|
if (unlikely(code < 0)) {
|
|
MARS_ERR("BIO ERROR %d (old=%d)\n", code, bf->bf_bio_status);
|
|
// this can race, but we don't worry about the exact error code
|
|
bf->bf_bio_status = code;
|
|
}
|
|
|
|
CHECK_SPIN(&bf->bf_bio_count, 1);
|
|
if (!atomic_dec_and_test(&bf->bf_bio_count))
|
|
return;
|
|
|
|
MARS_DBG("_buf_bio_callback() ZERO_COUNT mref=%p bio=%p bf=%p code=%d\n", mref_a->object, bio, bf, code);
|
|
|
|
brick = bf->bf_brick;
|
|
|
|
// get an extra reference, to avoid freeing bf underneath during callbacks
|
|
CHECK_SPIN(&bf->bf_count, 1);
|
|
atomic_inc(&bf->bf_count);
|
|
|
|
traced_lock(&brick->brick_lock, flags);
|
|
|
|
// update flags. this must be done before the callbacks.
|
|
old_flags = bf->bf_flags;
|
|
if (!bf->bf_bio_status && (old_flags & MARS_REF_READING)) {
|
|
bf->bf_flags |= MARS_REF_UPTODATE;
|
|
}
|
|
// clear the flags, callbacks must not see them. may be re-enabled later.
|
|
bf->bf_flags &= ~(MARS_REF_READING | MARS_REF_WRITING);
|
|
|
|
/* Remember current version of pending list.
|
|
* This is necessary because later the callbacks might
|
|
* change it underneath.
|
|
*/
|
|
if (!list_empty(&bf->bf_io_pending_anchor)) {
|
|
struct list_head *next = bf->bf_io_pending_anchor.next;
|
|
list_del_init(&bf->bf_io_pending_anchor);
|
|
list_add_tail(&tmp, next);
|
|
}
|
|
|
|
/* Move pending jobs to work.
|
|
* This is in essence an automatic restart mechanism.
|
|
* do this before the callbacks, because they may start
|
|
* new IOs. If not done in the right order, this could violate
|
|
* IO ordering semantics.
|
|
*/
|
|
while (!list_empty(&bf->bf_again_write_pending_anchor)) {
|
|
struct buf_mars_ref_aspect *mref_a = container_of(bf->bf_again_write_pending_anchor.next, struct buf_mars_ref_aspect, bfc_pending_head);
|
|
struct mars_ref_object *mref = mref_a->object;
|
|
if (mref_a->bfa_bf != bf) {
|
|
MARS_ERR("bad pointers %p != %p\n", mref_a->bfa_bf, bf);
|
|
}
|
|
#if 1
|
|
if (!(++count % 1000)) {
|
|
MARS_ERR("endless loop 1\n");
|
|
}
|
|
#endif
|
|
list_del_init(&mref_a->bfc_pending_head);
|
|
list_add_tail(&mref_a->bfc_pending_head, &bf->bf_io_pending_anchor);
|
|
|
|
// re-enable flags
|
|
bf->bf_flags |= MARS_REF_WRITING;
|
|
bf->bf_bio_status = 0;
|
|
|
|
if (!start_len) {
|
|
// first time: only flush the affected area
|
|
start_data = mref->ref_data;
|
|
start_pos = mref->ref_pos;
|
|
start_len = mref->ref_len;
|
|
} else if (start_data != mref->ref_data ||
|
|
start_pos != mref->ref_pos ||
|
|
start_len != mref->ref_len) {
|
|
// another time: flush the whole buffer
|
|
start_data = bf->bf_data;
|
|
start_pos = bf->bf_pos;
|
|
start_len = brick->backing_size;
|
|
}
|
|
}
|
|
|
|
traced_unlock(&brick->brick_lock, flags);
|
|
|
|
/* Signal success by calling all callbacks.
|
|
* Thanks to the tmp list, we can do this outside the spinlock.
|
|
*/
|
|
count = 0;
|
|
while (!list_empty(&tmp)) {
|
|
struct buf_mars_ref_aspect *mref_a = container_of(tmp.next, struct buf_mars_ref_aspect, bfc_pending_head);
|
|
struct mars_ref_object *mref = mref_a->object;
|
|
|
|
if (mref_a->bfa_bf != bf) {
|
|
MARS_ERR("bad pointers %p != %p\n", mref_a->bfa_bf, bf);
|
|
}
|
|
#if 1
|
|
if (!(++count % 1000)) {
|
|
MARS_ERR("endless loop 2\n");
|
|
}
|
|
#endif
|
|
CHECK_SPIN(&mref->ref_count, 1);
|
|
list_del_init(&mref_a->bfc_pending_head);
|
|
|
|
// update infos for callbacks, they may inspect it.
|
|
mref->ref_flags = bf->bf_flags;
|
|
mref->cb_error = bf->bf_bio_status;
|
|
|
|
atomic_dec(&brick->nr_io_pending);
|
|
|
|
mref->cb_ref_endio(mref);
|
|
|
|
_buf_ref_put(mref_a);
|
|
}
|
|
|
|
if (start_len) {
|
|
MARS_DBG("ATTENTION %d\n", start_len);
|
|
_buf_make_bios(brick, bf, start_data, start_pos, start_len, WRITE);
|
|
}
|
|
// drop the extra reference from above
|
|
__bf_put(bf);
|
|
}
|
|
|
|
static void buf_ref_io(struct buf_output *output, struct mars_ref_object *mref, int rw)
|
|
{
|
|
struct buf_brick *brick = output->brick;
|
|
struct buf_mars_ref_aspect *mref_a;
|
|
struct buf_head *bf;
|
|
void *start_data = NULL;
|
|
loff_t start_pos = 0;
|
|
int start_len = 0;
|
|
int status = -EINVAL;
|
|
bool delay = false;
|
|
unsigned long flags;
|
|
|
|
if (unlikely(!mref)) {
|
|
MARS_FAT("internal problem: forgotten to supply mref\n");
|
|
goto fatal;
|
|
}
|
|
mref_a = buf_mars_ref_get_aspect(output, mref);
|
|
if (unlikely(!mref_a)) {
|
|
MARS_ERR("internal problem: mref aspect does not work\n");
|
|
goto fatal;
|
|
}
|
|
|
|
/* Grab an extra reference.
|
|
* This will be released later in _buf_bio_callback() after
|
|
* calling the callbacks.
|
|
*/
|
|
CHECK_SPIN(&mref->ref_count, 1);
|
|
atomic_inc(&mref->ref_count);
|
|
|
|
bf = mref_a->bfa_bf;
|
|
if (unlikely(!bf)) {
|
|
MARS_ERR("internal problem: forgotten bf\n");
|
|
goto callback;
|
|
}
|
|
|
|
CHECK_SPIN(&bf->bf_count, 1);
|
|
|
|
if (rw != READ) {
|
|
if (unlikely(mref->ref_may_write == READ)) {
|
|
MARS_ERR("sorry, forgotten to set ref_may_write\n");
|
|
goto callback;
|
|
}
|
|
if (unlikely(!(bf->bf_flags & MARS_REF_UPTODATE))) {
|
|
MARS_ERR("sorry, writing is only allowed on UPTODATE buffers\n");
|
|
goto callback;
|
|
}
|
|
}
|
|
|
|
mref->ref_rw = rw;
|
|
|
|
#if 1
|
|
if (jiffies - brick->last_jiffies >= 30 * HZ) {
|
|
int hit = atomic_read(&brick->hit_count);
|
|
int miss = atomic_read(&brick->miss_count);
|
|
int perc = hit * 100 * 100 / (hit + miss);
|
|
brick->last_jiffies = jiffies;
|
|
MARS_INF("STATISTICS: hashed=%d alloc=%d io_pending=%d hit=%d (%d.%02d%%) miss=%d io=%d\n", brick->hashed_count, brick->alloc_count, atomic_read(&brick->nr_io_pending), hit, perc / 100, perc % 100, miss, atomic_read(&brick->io_count));
|
|
}
|
|
#endif
|
|
|
|
traced_lock(&brick->brick_lock, flags);
|
|
|
|
if (!list_empty(&mref_a->bfc_pending_head)) {
|
|
MARS_ERR("trying to start IO on an already started mref\n");
|
|
goto already_done;
|
|
}
|
|
|
|
if (rw) { // WRITE
|
|
if (bf->bf_flags & MARS_REF_READING) {
|
|
MARS_ERR("bad bf_flags %d\n", bf->bf_flags);
|
|
}
|
|
if (!(bf->bf_flags & MARS_REF_WRITING)) {
|
|
// by definition, a writeout buffer is uptodate
|
|
bf->bf_flags |= (MARS_REF_WRITING | MARS_REF_UPTODATE);
|
|
bf->bf_bio_status = 0;
|
|
#if 1
|
|
start_data = mref->ref_data;
|
|
start_pos = mref->ref_pos;
|
|
start_len = mref->ref_len;
|
|
#else // only for testing: write the full buffer
|
|
start_data = (void*)((unsigned long)mref->ref_data & ~(unsigned long)(brick->backing_size - 1));
|
|
start_pos = mref->ref_pos & ~(loff_t)(brick->backing_size - 1);
|
|
start_len = brick->backing_size;
|
|
#endif
|
|
list_add(&mref_a->bfc_pending_head, &bf->bf_io_pending_anchor);
|
|
delay = true;
|
|
} else {
|
|
list_add(&mref_a->bfc_pending_head, &bf->bf_again_write_pending_anchor);
|
|
delay = true;
|
|
MARS_DBG("postponing %lld %d\n", mref->ref_pos, mref->ref_len);
|
|
}
|
|
} else { // READ
|
|
if (bf->bf_flags & (MARS_REF_UPTODATE | MARS_REF_WRITING)) {
|
|
goto already_done;
|
|
}
|
|
if (!(bf->bf_flags & MARS_REF_READING)) {
|
|
bf->bf_flags |= MARS_REF_READING;
|
|
bf->bf_bio_status = 0;
|
|
|
|
// always read the whole buffer.
|
|
start_data = (void*)((unsigned long)mref->ref_data & ~(unsigned long)(brick->backing_size - 1));
|
|
start_pos = mref->ref_pos & ~(loff_t)(brick->backing_size - 1);
|
|
start_len = brick->backing_size;
|
|
}
|
|
list_add(&mref_a->bfc_pending_head, &bf->bf_io_pending_anchor);
|
|
delay = true;
|
|
}
|
|
|
|
mref->ref_flags = bf->bf_flags;
|
|
mref->cb_error = bf->bf_bio_status;
|
|
|
|
if (likely(delay)) {
|
|
atomic_inc(&brick->nr_io_pending);
|
|
atomic_inc(&brick->io_count);
|
|
}
|
|
|
|
traced_unlock(&brick->brick_lock, flags);
|
|
|
|
if (!start_len) {
|
|
// nothing to start, IO is already started.
|
|
goto no_callback;
|
|
}
|
|
|
|
status = _buf_make_bios(brick, bf, start_data, start_pos, start_len, rw);
|
|
if (likely(status >= 0)) {
|
|
/* No immediate callback, this time.
|
|
* Callbacks will be called later from _buf_bio_callback().
|
|
*/
|
|
goto no_callback;
|
|
}
|
|
|
|
MARS_ERR("error %d during buf_ref_io()\n", status);
|
|
buf_ref_put(output, mref);
|
|
goto callback;
|
|
|
|
already_done:
|
|
mref->ref_flags = bf->bf_flags;
|
|
status = bf->bf_bio_status;
|
|
|
|
traced_unlock(&brick->brick_lock, flags);
|
|
|
|
callback:
|
|
mref->cb_error = status;
|
|
|
|
mref->cb_ref_endio(mref);
|
|
|
|
no_callback:
|
|
if (!delay) {
|
|
buf_ref_put(output, mref);
|
|
} // else the ref_put() will be later carried out upon IO completion.
|
|
|
|
fatal: // no chance to call callback: may produce hanging tasks :(
|
|
;
|
|
}
|
|
|
|
//////////////// object / aspect constructors / destructors ///////////////
|
|
|
|
static int buf_mars_ref_aspect_init_fn(struct generic_aspect *_ini, void *_init_data)
|
|
{
|
|
struct buf_mars_ref_aspect *ini = (void*)_ini;
|
|
ini->bfa_bf = NULL;
|
|
INIT_LIST_HEAD(&ini->bfc_pending_head);
|
|
INIT_LIST_HEAD(&ini->tmp_head);
|
|
return 0;
|
|
}
|
|
|
|
MARS_MAKE_STATICS(buf);
|
|
|
|
////////////////////// brick constructors / destructors ////////////////////
|
|
|
|
static int buf_brick_construct(struct buf_brick *brick)
|
|
{
|
|
int i;
|
|
brick->backing_order = 5; // TODO: make this configurable
|
|
brick->backing_size = PAGE_SIZE << brick->backing_order;
|
|
brick->max_count = 32; // TODO: make this configurable
|
|
brick->hashed_count = 0;
|
|
brick->alloc_count = 0;
|
|
atomic_set(&brick->nr_io_pending, 0);
|
|
spin_lock_init(&brick->brick_lock);
|
|
INIT_LIST_HEAD(&brick->free_anchor);
|
|
INIT_LIST_HEAD(&brick->lru_anchor);
|
|
for (i = 0; i < MARS_BUF_HASH_MAX; i++) {
|
|
INIT_LIST_HEAD(&brick->cache_anchors[i]);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static int buf_output_construct(struct buf_output *output)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
static int buf_brick_destruct(struct buf_brick *brick)
|
|
{
|
|
unsigned long flags;
|
|
|
|
traced_lock(&brick->brick_lock, flags);
|
|
|
|
brick->max_count = 0;
|
|
__lru_free(brick);
|
|
__prune_cache(brick, 0, &flags);
|
|
|
|
traced_unlock(&brick->brick_lock, flags);
|
|
|
|
return 0;
|
|
}
|
|
|
|
///////////////////////// static structs ////////////////////////
|
|
|
|
static struct buf_brick_ops buf_brick_ops = {
|
|
};
|
|
|
|
static struct buf_output_ops buf_output_ops = {
|
|
.make_object_layout = buf_make_object_layout,
|
|
.mars_get_info = buf_get_info,
|
|
.mars_ref_get = buf_ref_get,
|
|
.mars_ref_put = buf_ref_put,
|
|
.mars_ref_io = buf_ref_io,
|
|
};
|
|
|
|
static const struct buf_input_type buf_input_type = {
|
|
.type_name = "buf_input",
|
|
.input_size = sizeof(struct buf_input),
|
|
};
|
|
|
|
static const struct buf_input_type *buf_input_types[] = {
|
|
&buf_input_type,
|
|
};
|
|
|
|
static const struct buf_output_type buf_output_type = {
|
|
.type_name = "buf_output",
|
|
.output_size = sizeof(struct buf_output),
|
|
.master_ops = &buf_output_ops,
|
|
.output_construct = &buf_output_construct,
|
|
.aspect_types = buf_aspect_types,
|
|
.layout_code = {
|
|
[BRICK_OBJ_MARS_REF] = LAYOUT_ALL,
|
|
}
|
|
};
|
|
|
|
static const struct buf_output_type *buf_output_types[] = {
|
|
&buf_output_type,
|
|
};
|
|
|
|
const struct buf_brick_type buf_brick_type = {
|
|
.type_name = "buf_brick",
|
|
.brick_size = sizeof(struct buf_brick),
|
|
.max_inputs = 1,
|
|
.max_outputs = 1,
|
|
.master_ops = &buf_brick_ops,
|
|
.default_input_types = buf_input_types,
|
|
.default_output_types = buf_output_types,
|
|
.brick_construct = &buf_brick_construct,
|
|
.brick_destruct = &buf_brick_destruct,
|
|
};
|
|
EXPORT_SYMBOL_GPL(buf_brick_type);
|
|
|
|
////////////////// module init stuff /////////////////////////
|
|
|
|
static int __init init_buf(void)
|
|
{
|
|
printk(MARS_INFO "init_buf()\n");
|
|
return buf_register_brick_type();
|
|
}
|
|
|
|
static void __exit exit_buf(void)
|
|
{
|
|
printk(MARS_INFO "exit_buf()\n");
|
|
buf_unregister_brick_type();
|
|
}
|
|
|
|
MODULE_DESCRIPTION("MARS buf brick");
|
|
MODULE_AUTHOR("Thomas Schoebel-Theuer <tst@1und1.de>");
|
|
MODULE_LICENSE("GPL");
|
|
|
|
module_init(init_buf);
|
|
module_exit(exit_buf);
|