drbd: get rid of bio_split, allow bios of "arbitrary" size
Where "arbitrary" size is currently 1 MiB, which is the BIO_MAX_SIZE for architectures with 4k PAGE_CACHE_SIZE (most). Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com> Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
This commit is contained in:
Lars Ellenberg
Philipp Reisner
Родитель
7726547e67
Коммит
23361cf32b
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@ -1326,8 +1326,16 @@ struct bm_extent {
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#endif
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#endif
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#define HT_SHIFT 8
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#define DRBD_MAX_BIO_SIZE (1U<<(9+HT_SHIFT))
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/* BIO_MAX_SIZE is 256 * PAGE_CACHE_SIZE,
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* so for typical PAGE_CACHE_SIZE of 4k, that is (1<<20) Byte.
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* Since we may live in a mixed-platform cluster,
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* we limit us to a platform agnostic constant here for now.
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* A followup commit may allow even bigger BIO sizes,
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* once we thought that through. */
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#define DRBD_MAX_BIO_SIZE (1 << 20)
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#if DRBD_MAX_BIO_SIZE > BIO_MAX_SIZE
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#error Architecture not supported: DRBD_MAX_BIO_SIZE > BIO_MAX_SIZE
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#endif
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#define DRBD_MAX_BIO_SIZE_SAFE (1 << 12) /* Works always = 4k */
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#define DRBD_MAX_SIZE_H80_PACKET (1 << 15) /* The old header only allows packets up to 32Kib data */
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@ -2231,20 +2239,20 @@ static inline bool may_inc_ap_bio(struct drbd_conf *mdev)
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return true;
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}
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static inline bool inc_ap_bio_cond(struct drbd_conf *mdev, int count)
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static inline bool inc_ap_bio_cond(struct drbd_conf *mdev)
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{
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bool rv = false;
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spin_lock_irq(&mdev->tconn->req_lock);
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rv = may_inc_ap_bio(mdev);
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if (rv)
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atomic_add(count, &mdev->ap_bio_cnt);
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atomic_inc(&mdev->ap_bio_cnt);
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spin_unlock_irq(&mdev->tconn->req_lock);
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return rv;
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}
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static inline void inc_ap_bio(struct drbd_conf *mdev, int count)
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static inline void inc_ap_bio(struct drbd_conf *mdev)
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{
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/* we wait here
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* as long as the device is suspended
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@ -2254,7 +2262,7 @@ static inline void inc_ap_bio(struct drbd_conf *mdev, int count)
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* to avoid races with the reconnect code,
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* we need to atomic_inc within the spinlock. */
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wait_event(mdev->misc_wait, inc_ap_bio_cond(mdev, count));
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wait_event(mdev->misc_wait, inc_ap_bio_cond(mdev));
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}
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static inline void dec_ap_bio(struct drbd_conf *mdev)
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@ -998,7 +998,6 @@ fail_and_free_req:
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int drbd_make_request(struct request_queue *q, struct bio *bio)
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{
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unsigned int s_enr, e_enr;
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struct drbd_conf *mdev = (struct drbd_conf *) q->queuedata;
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unsigned long start_time;
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@ -1010,93 +1009,30 @@ int drbd_make_request(struct request_queue *q, struct bio *bio)
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D_ASSERT(bio->bi_size > 0);
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D_ASSERT(IS_ALIGNED(bio->bi_size, 512));
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/* to make some things easier, force alignment of requests within the
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* granularity of our hash tables */
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s_enr = bio->bi_sector >> HT_SHIFT;
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e_enr = (bio->bi_sector+(bio->bi_size>>9)-1) >> HT_SHIFT;
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if (likely(s_enr == e_enr)) {
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inc_ap_bio(mdev, 1);
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return __drbd_make_request(mdev, bio, start_time);
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}
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/* can this bio be split generically?
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* Maybe add our own split-arbitrary-bios function. */
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if (bio->bi_vcnt != 1 || bio->bi_idx != 0 || bio->bi_size > DRBD_MAX_BIO_SIZE) {
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/* rather error out here than BUG in bio_split */
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dev_err(DEV, "bio would need to, but cannot, be split: "
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"(vcnt=%u,idx=%u,size=%u,sector=%llu)\n",
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bio->bi_vcnt, bio->bi_idx, bio->bi_size,
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(unsigned long long)bio->bi_sector);
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bio_endio(bio, -EINVAL);
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} else {
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/* This bio crosses some boundary, so we have to split it. */
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struct bio_pair *bp;
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/* works for the "do not cross hash slot boundaries" case
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* e.g. sector 262269, size 4096
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* s_enr = 262269 >> 6 = 4097
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* e_enr = (262269+8-1) >> 6 = 4098
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* HT_SHIFT = 6
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* sps = 64, mask = 63
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* first_sectors = 64 - (262269 & 63) = 3
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*/
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const sector_t sect = bio->bi_sector;
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const int sps = 1 << HT_SHIFT; /* sectors per slot */
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const int mask = sps - 1;
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const sector_t first_sectors = sps - (sect & mask);
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bp = bio_split(bio, first_sectors);
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/* we need to get a "reference count" (ap_bio_cnt)
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* to avoid races with the disconnect/reconnect/suspend code.
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* In case we need to split the bio here, we need to get three references
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* atomically, otherwise we might deadlock when trying to submit the
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* second one! */
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inc_ap_bio(mdev, 3);
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D_ASSERT(e_enr == s_enr + 1);
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while (__drbd_make_request(mdev, &bp->bio1, start_time))
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inc_ap_bio(mdev, 1);
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while (__drbd_make_request(mdev, &bp->bio2, start_time))
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inc_ap_bio(mdev, 1);
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dec_ap_bio(mdev);
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bio_pair_release(bp);
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}
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return 0;
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inc_ap_bio(mdev);
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return __drbd_make_request(mdev, bio, start_time);
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}
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/* This is called by bio_add_page(). With this function we reduce
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* the number of BIOs that span over multiple DRBD_MAX_BIO_SIZEs
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* units (was AL_EXTENTs).
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/* This is called by bio_add_page().
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*
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* we do the calculation within the lower 32bit of the byte offsets,
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* since we don't care for actual offset, but only check whether it
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* would cross "activity log extent" boundaries.
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* q->max_hw_sectors and other global limits are already enforced there.
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*
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* We need to call down to our lower level device,
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* in case it has special restrictions.
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*
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* We also may need to enforce configured max-bio-bvecs limits.
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*
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* As long as the BIO is empty we have to allow at least one bvec,
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* regardless of size and offset. so the resulting bio may still
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* cross extent boundaries. those are dealt with (bio_split) in
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* drbd_make_request.
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* regardless of size and offset, so no need to ask lower levels.
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*/
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int drbd_merge_bvec(struct request_queue *q, struct bvec_merge_data *bvm, struct bio_vec *bvec)
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{
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struct drbd_conf *mdev = (struct drbd_conf *) q->queuedata;
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unsigned int bio_offset =
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(unsigned int)bvm->bi_sector << 9; /* 32 bit */
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unsigned int bio_size = bvm->bi_size;
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int limit, backing_limit;
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int limit = DRBD_MAX_BIO_SIZE;
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int backing_limit;
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limit = DRBD_MAX_BIO_SIZE
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- ((bio_offset & (DRBD_MAX_BIO_SIZE-1)) + bio_size);
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if (limit < 0)
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limit = 0;
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if (bio_size == 0) {
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if (limit <= bvec->bv_len)
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limit = bvec->bv_len;
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} else if (limit && get_ldev(mdev)) {
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if (bio_size && get_ldev(mdev)) {
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struct request_queue * const b =
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mdev->ldev->backing_bdev->bd_disk->queue;
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if (b->merge_bvec_fn) {
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