Hello, Dan.
Couple of comments.
On Thu, Feb 02, 2006 at 06:12:59PM -0700, Dan Williams (dan.j.williams@xxxxxxxxx) wrote:
...
> +/*
> + * Issue a copy data operation between a page in the stripe cache, and a bio.
> + * There are no alignment or size guarantees between the page or the
> + * bio except that there is some overlap.
> + * All iovecs in the bio must be considered.
> + *
> + * Assumes being called under sh->lock
> + *
> + * @dev_idx: the raid device index that is being modified
> + *
> + * Returns true if the copy is complete, returns false if copy is asynchronous
> + */
> +int md_issue_copy_data(int frombio, struct bio *bio,
> + struct page *page, sector_t sector,
> + struct stripe_head *sh, int dev_idx)
> +{
> + char *pa = page_address(page);
> + struct bio_vec *bvl;
> + int i, desc_cnt = 0, pio = 0;
> + int page_offset;
> + void *buf[2];
> + adma_engine_t *eng = sh->raid_conf->adma_engine;
> + adma_desc_t *desc = adma_get_desc(eng), *next_desc = 0;
> +
> + if(!test_bit(ADMA_ENG_CAP_COPY, &eng->flags))
> + pio++;
> +
> + if (bio->bi_sector >= sector)
> + page_offset = (signed)(bio->bi_sector - sector) * 512;
> + else
> + page_offset = (signed)(sector - bio->bi_sector) * -512;
> + bio_for_each_segment(bvl, bio, i) {
> + int len = bio_iovec_idx(bio,i)->bv_len;
> + int clen;
> + int b_offset = 0;
> +
> + if (page_offset < 0) {
> + b_offset = -page_offset;
> + page_offset += b_offset;
> + len -= b_offset;
> + }
> +
> + if (len > 0 && page_offset + len > STRIPE_SIZE)
> + clen = STRIPE_SIZE - page_offset;
> + else clen = len;
> +
> + if (clen > 0) {
> + char *ba = __bio_kmap_atomic(bio, i, KM_USER0);
> +
> + if (desc_cnt) {
> + eng->queue_desc(desc, MD_ADMA_QUEUE);
> + next_desc = adma_get_desc(eng);
> + if (next_desc) adma_set_desc_flags(desc, ADMA_AUTO_REAP);
> + }
> +
> + if (frombio) {
> + buf[0] = pa+page_offset;
> + buf[1] = ba+b_offset;
> + } else {
> + buf[0] = ba+b_offset;
> + buf[1] = pa+page_offset;
> + }
> +
> + if (pio) goto pio_memcpy;
> +
> + /* if the adma engine can not access the bio page directly
> + * (pio_adma on highmem platforms or dma address restrictions)
> + * then we must copy synchronously.
> + * i.e. we can't / shouldn't hold a true atomic mapping while the
> + * adma_engine performs an asynchronous memcpy
> + */
> + #ifdef CONFIG_HIGHMEM
> + if(!test_bit(ADMA_ENG_CAP_HIGHMEM, &eng->flags))
> + goto pio_memcpy;
> + #endif
> +
> +
> + /* handle memory allocation failures:
> + * if we fail to allocate the necessary structures then
> + * (re)do everything as a pio memcpy. If some descriptors have
> + * already been successfully queued then we need to run
> + * the adma thread to get them cleaned up
> + */
> + if (unlikely(!desc || (desc_cnt && !next_desc))) {
> + if (desc_cnt) {
> + /* we run the thread directly since we are not
> + * preemptible
> + */
> + adma_run(eng);
> + /* we busy wait on prev_desc so
> + * that the pio operation does not
> + * conflict with the engine.
> + */
> + adma_spin_wait_desc(desc);
> + adma_put_desc(desc);
> + desc_cnt = 0;
> + } else if (desc) /* we don't have args, and never will */
> + adma_put_desc(desc);
> +
> + goto pio_memcpy;
> + }
> +
> + if (desc_cnt) {
> + desc = next_desc;
> + next_desc = NULL;
> + }
> +
> + eng->build_desc(desc, ADMA_COPY, buf, ARRAY_SIZE(buf), clen, 0);
> + desc_cnt++;
> + continue;
It looks like if pio mode is not enabled and memory allocation
succeds bio mapping is leaked?
> +
> +pio_memcpy: pio++;
> + memcpy(buf[0], buf[1], clen);
> + __bio_kunmap_atomic(ba, KM_USER0);
> +
> + }
> + if (clen < len) /* hit end of page */
> + break;
> + page_offset += len;
> + }
> +
> + if (desc) { /* queue and run the final descriptor */
> + adma_set_desc_flags(desc, 0);
> + adma_set_callback(desc, md_adma_copy_data_callback, sh, dev_idx);
> + eng->queue_desc(desc, MD_ADMA_QUEUE);
> + if(!frombio) { /* we are reading so client expects data immediately */
> + adma_run(eng);
> + adma_spin_wait_desc(desc);
> + } else adma_wakeup_thread(eng->thread);
> + } else if (pio)
> + __md_adma_copy_data_callback(sh, dev_idx);
> +
> + return pio;
> +}
> +
> +#define check_xor() do { \
> +if (likely(desc)) \
> + max_sources = adma_get_source_count(eng); \
> +else \
> + max_sources = MAX_XOR_BLOCKS; \
> +if (count == max_sources || last || mid) { \
> + if (desc) { \
> + eng->build_desc(desc, ADMA_XOR, ptr, count, STRIPE_SIZE, 0);\
> + if (last) { \
> + adma_set_callback(desc, raid5_adma_xor_callback, sh, method);\
> + next_desc = NULL; \
> + } else { \
> + next_desc = adma_get_desc(eng); \
> + if (likely(next_desc)) \
> + adma_set_desc_flags(desc, ADMA_AUTO_REAP); \
> + } \
> + eng->queue_desc(desc, last ? 1 : MD_ADMA_QUEUE); \
> + if (likely(!last) && unlikely(!next_desc)) { \
> + adma_run(eng); \
> + adma_spin_wait_desc(desc); \
> + adma_put_desc(desc); \
> + } \
> + desc = last ? desc : next_desc; \
> + } else xor_block(count, STRIPE_SIZE, ptr); \
> + count = 1; \
> +} \
> +} while(0)
Ugh...
Maybe better to place such a macro into inline function?
--
Evgeniy Polyakov
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