kernel/linux.git/drivers/mmc/core/queue.c, branch linux-4.20.y

mmc: block: Fix unsupported parallel dispatch of requests

2018-08-21T14:12:41+00:00

The mmc block driver does not support parallel dispatch of requests. In normal circumstances, all requests are anyway funneled through a single work item, so parallel dispatch never happens. However it can happen if there is no elevator. Fix that by detecting if a dispatch is in progress and returning busy (BLK_STS_RESOURCE) in that case Fixes: 81196976ed94 ("mmc: block: Add blk-mq support") Cc: stable@vger.kernel.org # v4.16+ Signed-off-by: Adrian Hunter Signed-off-by: Ulf Hansson

mmc: complete requests from ->timeout

2018-05-29T14:59:21+00:00

By completing the request entirely in the driver we can remove the BLK_EH_HANDLED return value and thus the split responsibility between the driver and the block layer that has been causing trouble. [While this keeps existing behavior it seems to mismatch the comment, maintainers please chime in!] Signed-off-by: Christoph Hellwig Reviewed-by: Hannes Reinecke Signed-off-by: Jens Axboe

block: Use blk_queue_flag_() in drivers instead of queue_flag_()

2018-03-08T21:13:48+00:00

This patch has been generated as follows: for verb in set_unlocked clear_unlocked set clear; do replace-in-files queue_flag_${verb} blk_queue_flag_${verb%_unlocked} \ $(git grep -lw queue_flag_${verb} drivers block/bsg*) done Except for protecting all queue flag changes with the queue lock this patch does not change any functionality. Cc: Mike Snitzer Cc: Shaohua Li Cc: Christoph Hellwig Cc: Hannes Reinecke Cc: Ming Lei Signed-off-by: Bart Van Assche Reviewed-by: Martin K. Petersen Reviewed-by: Johannes Thumshirn Acked-by: Martin K. Petersen Signed-off-by: Jens Axboe

mmc: block: Remove code no longer needed after the switch to blk-mq

2017-12-11T12:02:22+00:00

Remove code no longer needed after the switch to blk-mq. Signed-off-by: Adrian Hunter Acked-by: Linus Walleij Tested-by: Linus Walleij Signed-off-by: Ulf Hansson

mmc: block: make function mmc_cqe_issue_type static

2017-12-11T11:48:05+00:00

The function mmc_cqe_issue_type is local to the source and does not need to be in global scope, so make it static. Cleans up sparse warning: drivers/mmc/core/queue.c:62:21: warning: symbol 'mmc_cqe_issue_type' was not declared. Should it be static? Signed-off-by: Colin Ian King Acked-by: Adrian Hunter Signed-off-by: Ulf Hansson

mmc: block: blk-mq: Add support for direct completion

2017-12-11T11:44:35+00:00

For blk-mq, add support for completing requests directly in the ->done callback. That means that error handling and urgent background operations must be handled by recovery_work in that case. Signed-off-by: Adrian Hunter Acked-by: Linus Walleij Signed-off-by: Ulf Hansson Tested-by: Linus Walleij

mmc: block: Add CQE support

2017-12-11T11:44:34+00:00

Add CQE support to the block driver, including: - optionally using DCMD for flush requests - "manually" issuing discard requests - issuing read / write requests to the CQE - supporting block-layer timeouts - handling recovery - supporting re-tuning CQE offers 25% - 50% better random multi-threaded I/O. There is a slight (e.g. 2%) drop in sequential read speed but no observable change to sequential write. CQE automatically sends the commands to complete requests. However it only supports reads / writes and so-called "direct commands" (DCMD). Furthermore DCMD is limited to one command at a time, but discards require 3 commands. That makes issuing discards through CQE very awkward, but some CQE's don't support DCMD anyway. So for discards, the existing non-CQE approach is taken, where the mmc core code issues the 3 commands one at a time i.e. mmc_erase(). Where DCMD is used, is for issuing flushes. Signed-off-by: Adrian Hunter Acked-by: Linus Walleij Signed-off-by: Ulf Hansson Tested-by: Linus Walleij

mmc: block: Add blk-mq support

2017-12-11T11:44:33+00:00

Define and use a blk-mq queue. Discards and flushes are processed synchronously, but reads and writes asynchronously. In order to support slow DMA unmapping, DMA unmapping is not done until after the next request is started. That means the request is not completed until then. If there is no next request then the completion is done by queued work. Signed-off-by: Adrian Hunter Acked-by: Linus Walleij Signed-off-by: Ulf Hansson Tested-by: Linus Walleij

mmc: block: Simplify cleaning up the queue

2017-12-11T11:44:31+00:00

Use blk_cleanup_queue() to shutdown the queue when the driver is removed, and instead get an extra reference to the queue to prevent the queue being freed before the final mmc_blk_put(). Signed-off-by: Adrian Hunter Acked-by: Linus Walleij Signed-off-by: Ulf Hansson Tested-by: Linus Walleij

mmc: block: No need to export mmc_cleanup_queue()