From 1122c0c1cc71f740fa4d5f14f239194e06a1d5e7 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 17 Jun 2024 08:04:40 +0200 Subject: block: move cache control settings out of queue->flags Move the cache control settings into the queue_limits so that the flags can be set atomically with the device queue frozen. Add new features and flags field for the driver set flags, and internal (usually sysfs-controlled) flags in the block layer. Note that we'll eventually remove enough field from queue_limits to bring it back to the previous size. The disable flag is inverted compared to the previous meaning, which means it now survives a rescan, similar to the max_sectors and max_discard_sectors user limits. The FLUSH and FUA flags are now inherited by blk_stack_limits, which simplified the code in dm a lot, but also causes a slight behavior change in that dm-switch and dm-unstripe now advertise a write cache despite setting num_flush_bios to 0. The I/O path will handle this gracefully, but as far as I can tell the lack of num_flush_bios and thus flush support is a pre-existing data integrity bug in those targets that really needs fixing, after which a non-zero num_flush_bios should be required in dm for targets that map to underlying devices. Signed-off-by: Christoph Hellwig Acked-by: Ulf Hansson Reviewed-by: Damien Le Moal Reviewed-by: Hannes Reinecke Link: https://lore.kernel.org/r/20240617060532.127975-14-hch@lst.de Signed-off-by: Jens Axboe --- block/blk-sysfs.c | 29 +++++++++++++++++++---------- 1 file changed, 19 insertions(+), 10 deletions(-) (limited to 'block/blk-sysfs.c') diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index 5c787965b7d0..4f524c1d5e08 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -423,32 +423,41 @@ static ssize_t queue_io_timeout_store(struct request_queue *q, const char *page, static ssize_t queue_wc_show(struct request_queue *q, char *page) { - if (test_bit(QUEUE_FLAG_WC, &q->queue_flags)) - return sprintf(page, "write back\n"); - - return sprintf(page, "write through\n"); + if (q->limits.features & BLK_FLAGS_WRITE_CACHE_DISABLED) + return sprintf(page, "write through\n"); + return sprintf(page, "write back\n"); } static ssize_t queue_wc_store(struct request_queue *q, const char *page, size_t count) { + struct queue_limits lim; + bool disable; + int err; + if (!strncmp(page, "write back", 10)) { - if (!test_bit(QUEUE_FLAG_HW_WC, &q->queue_flags)) - return -EINVAL; - blk_queue_flag_set(QUEUE_FLAG_WC, q); + disable = false; } else if (!strncmp(page, "write through", 13) || - !strncmp(page, "none", 4)) { - blk_queue_flag_clear(QUEUE_FLAG_WC, q); + !strncmp(page, "none", 4)) { + disable = true; } else { return -EINVAL; } + lim = queue_limits_start_update(q); + if (disable) + lim.flags |= BLK_FLAGS_WRITE_CACHE_DISABLED; + else + lim.flags &= ~BLK_FLAGS_WRITE_CACHE_DISABLED; + err = queue_limits_commit_update(q, &lim); + if (err) + return err; return count; } static ssize_t queue_fua_show(struct request_queue *q, char *page) { - return sprintf(page, "%u\n", test_bit(QUEUE_FLAG_FUA, &q->queue_flags)); + return sprintf(page, "%u\n", !!(q->limits.features & BLK_FEAT_FUA)); } static ssize_t queue_dax_show(struct request_queue *q, char *page) -- cgit v1.2.3