diff options
author | Linus Walleij <linus.walleij@linaro.org> | 2016-11-25 10:35:00 +0100 |
---|---|---|
committer | Ulf Hansson <ulf.hansson@linaro.org> | 2016-11-29 09:05:27 +0100 |
commit | 03d640ae1f9b24b1d2a11f747143a1ecc0745019 (patch) | |
tree | ed58f4741abe40f2bc5f7d9b2d7d0e3702de06d2 /drivers/mmc/card/block.c | |
parent | d3c6aac3bdfe97b8b44db6a8aba59786cb9531dc (diff) | |
download | linux-03d640ae1f9b24b1d2a11f747143a1ecc0745019.tar.bz2 |
mmc: block: delete packed command support
I've had it with this code now.
The packed command support is a complex hurdle in the MMC/SD block
layer, around 500+ lines of code which was introduced in 2013 in
commit ce39f9d17c14 ("mmc: support packed write command for eMMC4.5
devices")
commit abd9ac144947 ("mmc: add packed command feature of eMMC4.5")
...and since then it has been rotting. The original author of the
code has disappeared from the community and the mail address is
bouncing.
For the code to be exercised the host must flag that it supports
packed commands, so in mmc_blk_prep_packed_list() which is called for
every single request, the following construction appears:
u8 max_packed_rw = 0;
if ((rq_data_dir(cur) == WRITE) &&
mmc_host_packed_wr(card->host))
max_packed_rw = card->ext_csd.max_packed_writes;
if (max_packed_rw == 0)
goto no_packed;
This has the following logical deductions:
- Only WRITE commands can really be packed, so the solution is
only half-done: we support packed WRITE but not packed READ.
The packed command support has not been finalized by supporting
reads in three years!
- mmc_host_packed_wr() is just a static inline that checks
host->caps2 & MMC_CAP2_PACKED_WR. The problem with this is
that NO upstream host sets this capability flag! No driver
in the kernel is using it, and we can't test it. Packed
command may be supported in out-of-tree code, but I doubt
it. I doubt that the code is even working anymore due to
other refactorings in the MMC block layer, who would
notice if patches affecting it broke packed commands?
No one.
- There is no Device Tree binding or code to mark a host as
supporting packed read or write commands, just this flag
in caps2, so for sure there are not any DT systems using
it either.
It has other problems as well: mmc_blk_prep_packed_list() is
speculatively picking requests out of the request queue with
blk_fetch_request() making the MMC/SD stack harder to convert
to the multiqueue block layer. By this we get rid of an
obstacle.
The way I see it this is just cruft littering the MMC/SD
stack.
Cc: Namjae Jeon <namjae.jeon@samsung.com>
Cc: Maya Erez <qca_merez@qca.qualcomm.com>
Acked-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Diffstat (limited to 'drivers/mmc/card/block.c')
-rw-r--r-- | drivers/mmc/card/block.c | 483 |
1 files changed, 17 insertions, 466 deletions
diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c index 6618126fcb9f..86ff28f84698 100644 --- a/drivers/mmc/card/block.c +++ b/drivers/mmc/card/block.c @@ -66,9 +66,6 @@ MODULE_ALIAS("mmc:block"); #define mmc_req_rel_wr(req) ((req->cmd_flags & REQ_FUA) && \ (rq_data_dir(req) == WRITE)) -#define PACKED_CMD_VER 0x01 -#define PACKED_CMD_WR 0x02 - static DEFINE_MUTEX(block_mutex); /* @@ -102,7 +99,6 @@ struct mmc_blk_data { unsigned int flags; #define MMC_BLK_CMD23 (1 << 0) /* Can do SET_BLOCK_COUNT for multiblock */ #define MMC_BLK_REL_WR (1 << 1) /* MMC Reliable write support */ -#define MMC_BLK_PACKED_CMD (1 << 2) /* MMC packed command support */ unsigned int usage; unsigned int read_only; @@ -126,12 +122,6 @@ struct mmc_blk_data { static DEFINE_MUTEX(open_lock); -enum { - MMC_PACKED_NR_IDX = -1, - MMC_PACKED_NR_ZERO, - MMC_PACKED_NR_SINGLE, -}; - module_param(perdev_minors, int, 0444); MODULE_PARM_DESC(perdev_minors, "Minors numbers to allocate per device"); @@ -139,17 +129,6 @@ static inline int mmc_blk_part_switch(struct mmc_card *card, struct mmc_blk_data *md); static int get_card_status(struct mmc_card *card, u32 *status, int retries); -static inline void mmc_blk_clear_packed(struct mmc_queue_req *mqrq) -{ - struct mmc_packed *packed = mqrq->packed; - - mqrq->cmd_type = MMC_PACKED_NONE; - packed->nr_entries = MMC_PACKED_NR_ZERO; - packed->idx_failure = MMC_PACKED_NR_IDX; - packed->retries = 0; - packed->blocks = 0; -} - static struct mmc_blk_data *mmc_blk_get(struct gendisk *disk) { struct mmc_blk_data *md; @@ -1420,111 +1399,12 @@ static enum mmc_blk_status mmc_blk_err_check(struct mmc_card *card, if (!brq->data.bytes_xfered) return MMC_BLK_RETRY; - if (mmc_packed_cmd(mq_mrq->cmd_type)) { - if (unlikely(brq->data.blocks << 9 != brq->data.bytes_xfered)) - return MMC_BLK_PARTIAL; - else - return MMC_BLK_SUCCESS; - } - if (blk_rq_bytes(req) != brq->data.bytes_xfered) return MMC_BLK_PARTIAL; return MMC_BLK_SUCCESS; } -static int mmc_packed_init(struct mmc_queue *mq, struct mmc_card *card) -{ - struct mmc_queue_req *mqrq_cur = &mq->mqrq[0]; - struct mmc_queue_req *mqrq_prev = &mq->mqrq[1]; - int ret = 0; - - - mqrq_cur->packed = kzalloc(sizeof(struct mmc_packed), GFP_KERNEL); - if (!mqrq_cur->packed) { - pr_warn("%s: unable to allocate packed cmd for mqrq_cur\n", - mmc_card_name(card)); - ret = -ENOMEM; - goto out; - } - - mqrq_prev->packed = kzalloc(sizeof(struct mmc_packed), GFP_KERNEL); - if (!mqrq_prev->packed) { - pr_warn("%s: unable to allocate packed cmd for mqrq_prev\n", - mmc_card_name(card)); - kfree(mqrq_cur->packed); - mqrq_cur->packed = NULL; - ret = -ENOMEM; - goto out; - } - - INIT_LIST_HEAD(&mqrq_cur->packed->list); - INIT_LIST_HEAD(&mqrq_prev->packed->list); - -out: - return ret; -} - -static void mmc_packed_clean(struct mmc_queue *mq) -{ - struct mmc_queue_req *mqrq_cur = &mq->mqrq[0]; - struct mmc_queue_req *mqrq_prev = &mq->mqrq[1]; - - kfree(mqrq_cur->packed); - mqrq_cur->packed = NULL; - kfree(mqrq_prev->packed); - mqrq_prev->packed = NULL; -} - -static enum mmc_blk_status mmc_blk_packed_err_check(struct mmc_card *card, - struct mmc_async_req *areq) -{ - struct mmc_queue_req *mq_rq = container_of(areq, struct mmc_queue_req, - mmc_active); - struct request *req = mq_rq->req; - struct mmc_packed *packed = mq_rq->packed; - enum mmc_blk_status status, check; - int err; - u8 *ext_csd; - - packed->retries--; - check = mmc_blk_err_check(card, areq); - err = get_card_status(card, &status, 0); - if (err) { - pr_err("%s: error %d sending status command\n", - req->rq_disk->disk_name, err); - return MMC_BLK_ABORT; - } - - if (status & R1_EXCEPTION_EVENT) { - err = mmc_get_ext_csd(card, &ext_csd); - if (err) { - pr_err("%s: error %d sending ext_csd\n", - req->rq_disk->disk_name, err); - return MMC_BLK_ABORT; - } - - if ((ext_csd[EXT_CSD_EXP_EVENTS_STATUS] & - EXT_CSD_PACKED_FAILURE) && - (ext_csd[EXT_CSD_PACKED_CMD_STATUS] & - EXT_CSD_PACKED_GENERIC_ERROR)) { - if (ext_csd[EXT_CSD_PACKED_CMD_STATUS] & - EXT_CSD_PACKED_INDEXED_ERROR) { - packed->idx_failure = - ext_csd[EXT_CSD_PACKED_FAILURE_INDEX] - 1; - check = MMC_BLK_PARTIAL; - } - pr_err("%s: packed cmd failed, nr %u, sectors %u, " - "failure index: %d\n", - req->rq_disk->disk_name, packed->nr_entries, - packed->blocks, packed->idx_failure); - } - kfree(ext_csd); - } - - return check; -} - static void mmc_blk_rw_rq_prep(struct mmc_queue_req *mqrq, struct mmc_card *card, int disable_multi, @@ -1685,222 +1565,6 @@ static void mmc_blk_rw_rq_prep(struct mmc_queue_req *mqrq, mmc_queue_bounce_pre(mqrq); } -static inline u8 mmc_calc_packed_hdr_segs(struct request_queue *q, - struct mmc_card *card) -{ - unsigned int hdr_sz = mmc_large_sector(card) ? 4096 : 512; - unsigned int max_seg_sz = queue_max_segment_size(q); - unsigned int len, nr_segs = 0; - - do { - len = min(hdr_sz, max_seg_sz); - hdr_sz -= len; - nr_segs++; - } while (hdr_sz); - - return nr_segs; -} - -static u8 mmc_blk_prep_packed_list(struct mmc_queue *mq, struct request *req) -{ - struct request_queue *q = mq->queue; - struct mmc_card *card = mq->card; - struct request *cur = req, *next = NULL; - struct mmc_blk_data *md = mq->blkdata; - struct mmc_queue_req *mqrq = mq->mqrq_cur; - bool en_rel_wr = card->ext_csd.rel_param & EXT_CSD_WR_REL_PARAM_EN; - unsigned int req_sectors = 0, phys_segments = 0; - unsigned int max_blk_count, max_phys_segs; - bool put_back = true; - u8 max_packed_rw = 0; - u8 reqs = 0; - - /* - * We don't need to check packed for any further - * operation of packed stuff as we set MMC_PACKED_NONE - * and return zero for reqs if geting null packed. Also - * we clean the flag of MMC_BLK_PACKED_CMD to avoid doing - * it again when removing blk req. - */ - if (!mqrq->packed) { - md->flags &= (~MMC_BLK_PACKED_CMD); - goto no_packed; - } - - if (!(md->flags & MMC_BLK_PACKED_CMD)) - goto no_packed; - - if ((rq_data_dir(cur) == WRITE) && - mmc_host_packed_wr(card->host)) - max_packed_rw = card->ext_csd.max_packed_writes; - - if (max_packed_rw == 0) - goto no_packed; - - if (mmc_req_rel_wr(cur) && - (md->flags & MMC_BLK_REL_WR) && !en_rel_wr) - goto no_packed; - - if (mmc_large_sector(card) && - !IS_ALIGNED(blk_rq_sectors(cur), 8)) - goto no_packed; - - mmc_blk_clear_packed(mqrq); - - max_blk_count = min(card->host->max_blk_count, - card->host->max_req_size >> 9); - if (unlikely(max_blk_count > 0xffff)) - max_blk_count = 0xffff; - - max_phys_segs = queue_max_segments(q); - req_sectors += blk_rq_sectors(cur); - phys_segments += cur->nr_phys_segments; - - if (rq_data_dir(cur) == WRITE) { - req_sectors += mmc_large_sector(card) ? 8 : 1; - phys_segments += mmc_calc_packed_hdr_segs(q, card); - } - - do { - if (reqs >= max_packed_rw - 1) { - put_back = false; - break; - } - - spin_lock_irq(q->queue_lock); - next = blk_fetch_request(q); - spin_unlock_irq(q->queue_lock); - if (!next) { - put_back = false; - break; - } - - if (mmc_large_sector(card) && - !IS_ALIGNED(blk_rq_sectors(next), 8)) - break; - - if (mmc_req_is_special(next)) - break; - - if (rq_data_dir(cur) != rq_data_dir(next)) - break; - - if (mmc_req_rel_wr(next) && - (md->flags & MMC_BLK_REL_WR) && !en_rel_wr) - break; - - req_sectors += blk_rq_sectors(next); - if (req_sectors > max_blk_count) - break; - - phys_segments += next->nr_phys_segments; - if (phys_segments > max_phys_segs) - break; - - list_add_tail(&next->queuelist, &mqrq->packed->list); - cur = next; - reqs++; - } while (1); - - if (put_back) { - spin_lock_irq(q->queue_lock); - blk_requeue_request(q, next); - spin_unlock_irq(q->queue_lock); - } - - if (reqs > 0) { - list_add(&req->queuelist, &mqrq->packed->list); - mqrq->packed->nr_entries = ++reqs; - mqrq->packed->retries = reqs; - return reqs; - } - -no_packed: - mqrq->cmd_type = MMC_PACKED_NONE; - return 0; -} - -static void mmc_blk_packed_hdr_wrq_prep(struct mmc_queue_req *mqrq, - struct mmc_card *card, - struct mmc_queue *mq) -{ - struct mmc_blk_request *brq = &mqrq->brq; - struct request *req = mqrq->req; - struct request *prq; - struct mmc_blk_data *md = mq->blkdata; - struct mmc_packed *packed = mqrq->packed; - bool do_rel_wr, do_data_tag; - __le32 *packed_cmd_hdr; - u8 hdr_blocks; - u8 i = 1; - - mqrq->cmd_type = MMC_PACKED_WRITE; - packed->blocks = 0; - packed->idx_failure = MMC_PACKED_NR_IDX; - - packed_cmd_hdr = packed->cmd_hdr; - memset(packed_cmd_hdr, 0, sizeof(packed->cmd_hdr)); - packed_cmd_hdr[0] = cpu_to_le32((packed->nr_entries << 16) | - (PACKED_CMD_WR << 8) | PACKED_CMD_VER); - hdr_blocks = mmc_large_sector(card) ? 8 : 1; - - /* - * Argument for each entry of packed group - */ - list_for_each_entry(prq, &packed->list, queuelist) { - do_rel_wr = mmc_req_rel_wr(prq) && (md->flags & MMC_BLK_REL_WR); - do_data_tag = (card->ext_csd.data_tag_unit_size) && - (prq->cmd_flags & REQ_META) && - (rq_data_dir(prq) == WRITE) && - blk_rq_bytes(prq) >= card->ext_csd.data_tag_unit_size; - /* Argument of CMD23 */ - packed_cmd_hdr[(i * 2)] = cpu_to_le32( - (do_rel_wr ? MMC_CMD23_ARG_REL_WR : 0) | - (do_data_tag ? MMC_CMD23_ARG_TAG_REQ : 0) | - blk_rq_sectors(prq)); - /* Argument of CMD18 or CMD25 */ - packed_cmd_hdr[((i * 2)) + 1] = cpu_to_le32( - mmc_card_blockaddr(card) ? - blk_rq_pos(prq) : blk_rq_pos(prq) << 9); - packed->blocks += blk_rq_sectors(prq); - i++; - } - - memset(brq, 0, sizeof(struct mmc_blk_request)); - brq->mrq.cmd = &brq->cmd; - brq->mrq.data = &brq->data; - brq->mrq.sbc = &brq->sbc; - brq->mrq.stop = &brq->stop; - - brq->sbc.opcode = MMC_SET_BLOCK_COUNT; - brq->sbc.arg = MMC_CMD23_ARG_PACKED | (packed->blocks + hdr_blocks); - brq->sbc.flags = MMC_RSP_R1 | MMC_CMD_AC; - - brq->cmd.opcode = MMC_WRITE_MULTIPLE_BLOCK; - brq->cmd.arg = blk_rq_pos(req); - if (!mmc_card_blockaddr(card)) - brq->cmd.arg <<= 9; - brq->cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_ADTC; - - brq->data.blksz = 512; - brq->data.blocks = packed->blocks + hdr_blocks; - brq->data.flags = MMC_DATA_WRITE; - - brq->stop.opcode = MMC_STOP_TRANSMISSION; - brq->stop.arg = 0; - brq->stop.flags = MMC_RSP_SPI_R1B | MMC_RSP_R1B | MMC_CMD_AC; - - mmc_set_data_timeout(&brq->data, card); - - brq->data.sg = mqrq->sg; - brq->data.sg_len = mmc_queue_map_sg(mq, mqrq); - - mqrq->mmc_active.mrq = &brq->mrq; - mqrq->mmc_active.err_check = mmc_blk_packed_err_check; - - mmc_queue_bounce_pre(mqrq); -} - static int mmc_blk_cmd_err(struct mmc_blk_data *md, struct mmc_card *card, struct mmc_blk_request *brq, struct request *req, int ret) @@ -1923,79 +1587,10 @@ static int mmc_blk_cmd_err(struct mmc_blk_data *md, struct mmc_card *card, if (blocks != (u32)-1) { ret = blk_end_request(req, 0, blocks << 9); } - } else { - if (!mmc_packed_cmd(mq_rq->cmd_type)) - ret = blk_end_request(req, 0, brq->data.bytes_xfered); - } - return ret; -} - -static int mmc_blk_end_packed_req(struct mmc_queue_req *mq_rq) -{ - struct request *prq; - struct mmc_packed *packed = mq_rq->packed; - int idx = packed->idx_failure, i = 0; - int ret = 0; - - while (!list_empty(&packed->list)) { - prq = list_entry_rq(packed->list.next); - if (idx == i) { - /* retry from error index */ - packed->nr_entries -= idx; - mq_rq->req = prq; - ret = 1; - - if (packed->nr_entries == MMC_PACKED_NR_SINGLE) { - list_del_init(&prq->queuelist); - mmc_blk_clear_packed(mq_rq); - } - return ret; - } - list_del_init(&prq->queuelist); - blk_end_request(prq, 0, blk_rq_bytes(prq)); - i++; } - - mmc_blk_clear_packed(mq_rq); return ret; } -static void mmc_blk_abort_packed_req(struct mmc_queue_req *mq_rq) -{ - struct request *prq; - struct mmc_packed *packed = mq_rq->packed; - - while (!list_empty(&packed->list)) { - prq = list_entry_rq(packed->list.next); - list_del_init(&prq->queuelist); - blk_end_request(prq, -EIO, blk_rq_bytes(prq)); - } - - mmc_blk_clear_packed(mq_rq); -} - -static void mmc_blk_revert_packed_req(struct mmc_queue *mq, - struct mmc_queue_req *mq_rq) -{ - struct request *prq; - struct request_queue *q = mq->queue; - struct mmc_packed *packed = mq_rq->packed; - - while (!list_empty(&packed->list)) { - prq = list_entry_rq(packed->list.prev); - if (prq->queuelist.prev != &packed->list) { - list_del_init(&prq->queuelist); - spin_lock_irq(q->queue_lock); - blk_requeue_request(mq->queue, prq); - spin_unlock_irq(q->queue_lock); - } else { - list_del_init(&prq->queuelist); - } - } - - mmc_blk_clear_packed(mq_rq); -} - static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *rqc) { struct mmc_blk_data *md = mq->blkdata; @@ -2006,15 +1601,10 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *rqc) struct mmc_queue_req *mq_rq; struct request *req = rqc; struct mmc_async_req *areq; - const u8 packed_nr = 2; - u8 reqs = 0; if (!rqc && !mq->mqrq_prev->req) return 0; - if (rqc) - reqs = mmc_blk_prep_packed_list(mq, rqc); - do { if (rqc) { /* @@ -2029,11 +1619,7 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *rqc) goto cmd_abort; } - if (reqs >= packed_nr) - mmc_blk_packed_hdr_wrq_prep(mq->mqrq_cur, - card, mq); - else - mmc_blk_rw_rq_prep(mq->mqrq_cur, card, 0, mq); + mmc_blk_rw_rq_prep(mq->mqrq_cur, card, 0, mq); areq = &mq->mqrq_cur->mmc_active; } else areq = NULL; @@ -2058,13 +1644,8 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *rqc) */ mmc_blk_reset_success(md, type); - if (mmc_packed_cmd(mq_rq->cmd_type)) { - ret = mmc_blk_end_packed_req(mq_rq); - break; - } else { - ret = blk_end_request(req, 0, - brq->data.bytes_xfered); - } + ret = blk_end_request(req, 0, + brq->data.bytes_xfered); /* * If the blk_end_request function returns non-zero even @@ -2101,8 +1682,7 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *rqc) err = mmc_blk_reset(md, card->host, type); if (!err) break; - if (err == -ENODEV || - mmc_packed_cmd(mq_rq->cmd_type)) + if (err == -ENODEV) goto cmd_abort; /* Fall through */ } @@ -2133,23 +1713,14 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *rqc) } if (ret) { - if (mmc_packed_cmd(mq_rq->cmd_type)) { - if (!mq_rq->packed->retries) - goto cmd_abort; - mmc_blk_packed_hdr_wrq_prep(mq_rq, card, mq); - mmc_start_req(card->host, - &mq_rq->mmc_active, NULL); - } else { - - /* - * In case of a incomplete request - * prepare it again and resend. - */ - mmc_blk_rw_rq_prep(mq_rq, card, - disable_multi, mq); - mmc_start_req(card->host, - &mq_rq->mmc_active, NULL); - } + /* + * In case of a incomplete request + * prepare it again and resend. + */ + mmc_blk_rw_rq_prep(mq_rq, card, + disable_multi, mq); + mmc_start_req(card->host, + &mq_rq->mmc_active, NULL); mq_rq->brq.retune_retry_done = retune_retry_done; } } while (ret); @@ -2157,15 +1728,11 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *rqc) return 1; cmd_abort: - if (mmc_packed_cmd(mq_rq->cmd_type)) { - mmc_blk_abort_packed_req(mq_rq); - } else { - if (mmc_card_removed(card)) - req->cmd_flags |= REQ_QUIET; - while (ret) - ret = blk_end_request(req, -EIO, - blk_rq_cur_bytes(req)); - } + if (mmc_card_removed(card)) + req->cmd_flags |= REQ_QUIET; + while (ret) + ret = blk_end_request(req, -EIO, + blk_rq_cur_bytes(req)); start_new_req: if (rqc) { @@ -2173,12 +1740,6 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *rqc) rqc->cmd_flags |= REQ_QUIET; blk_end_request_all(rqc, -EIO); } else { - /* - * If current request is packed, it needs to put back. - */ - if (mmc_packed_cmd(mq->mqrq_cur->cmd_type)) - mmc_blk_revert_packed_req(mq, mq->mqrq_cur); - mmc_blk_rw_rq_prep(mq->mqrq_cur, card, 0, mq); mmc_start_req(card->host, &mq->mqrq_cur->mmc_active, NULL); @@ -2361,14 +1922,6 @@ again: blk_queue_write_cache(md->queue.queue, true, true); } - if (mmc_card_mmc(card) && - (area_type == MMC_BLK_DATA_AREA_MAIN) && - (md->flags & MMC_BLK_CMD23) && - card->ext_csd.packed_event_en) { - if (!mmc_packed_init(&md->queue, card)) - md->flags |= MMC_BLK_PACKED_CMD; - } - return md; err_putdisk: @@ -2472,8 +2025,6 @@ static void mmc_blk_remove_req(struct mmc_blk_data *md) */ card = md->queue.card; mmc_cleanup_queue(&md->queue); - if (md->flags & MMC_BLK_PACKED_CMD) - mmc_packed_clean(&md->queue); if (md->disk->flags & GENHD_FL_UP) { device_remove_file(disk_to_dev(md->disk), &md->force_ro); if ((md->area_type & MMC_BLK_DATA_AREA_BOOT) && |