nvme: only reconfigure discard if necessary

Currently nvme reconfigures discard for every disk revalidation. This
is problematic because any O_WRONLY or O_RDWR open will trigger a
partition scan through udev/systemd, and we will reconfigure discard.
This blows away any user settings, like discard_max_bytes.

Only re-configure the user settable settings if we need to.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
[removed redundant queue flag setting]
Signed-off-by: Keith Busch <keith.busch@intel.com>

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 9df4f71..62262fa 100644 (file)
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1347,13 +1347,19 @@ static void nvme_set_chunk_size(struct nvme_ns *ns)
        blk_queue_chunk_sectors(ns->queue, rounddown_pow_of_two(chunk_size));
 }
 
-static void nvme_config_discard(struct nvme_ctrl *ctrl,
-               unsigned stream_alignment, struct request_queue *queue)
+static void nvme_config_discard(struct nvme_ns *ns)
 {
+       struct nvme_ctrl *ctrl = ns->ctrl;
+       struct request_queue *queue = ns->queue;
        u32 size = queue_logical_block_size(queue);
 
-       if (stream_alignment)
-               size *= stream_alignment;
+       if (!(ctrl->oncs & NVME_CTRL_ONCS_DSM)) {
+               blk_queue_flag_clear(QUEUE_FLAG_DISCARD, queue);
+               return;
+       }
+
+       if (ctrl->nr_streams && ns->sws && ns->sgs)
+               size *= ns->sws * ns->sgs;
 
        BUILD_BUG_ON(PAGE_SIZE / sizeof(struct nvme_dsm_range) <
                        NVME_DSM_MAX_RANGES);
@@ -1361,9 +1367,12 @@ static void nvme_config_discard(struct nvme_ctrl *ctrl,
        queue->limits.discard_alignment = 0;
        queue->limits.discard_granularity = size;
 
+       /* If discard is already enabled, don't reset queue limits */
+       if (blk_queue_flag_test_and_set(QUEUE_FLAG_DISCARD, queue))
+               return;
+
        blk_queue_max_discard_sectors(queue, UINT_MAX);
        blk_queue_max_discard_segments(queue, NVME_DSM_MAX_RANGES);
-       blk_queue_flag_set(QUEUE_FLAG_DISCARD, queue);
 
        if (ctrl->quirks & NVME_QUIRK_DEALLOCATE_ZEROES)
                blk_queue_max_write_zeroes_sectors(queue, UINT_MAX);
@@ -1407,10 +1416,6 @@ static void nvme_update_disk_info(struct gendisk *disk,
 {
        sector_t capacity = le64_to_cpup(&id->nsze) << (ns->lba_shift - 9);
        unsigned short bs = 1 << ns->lba_shift;
-       unsigned stream_alignment = 0;
-
-       if (ns->ctrl->nr_streams && ns->sws && ns->sgs)
-               stream_alignment = ns->sws * ns->sgs;
 
        blk_mq_freeze_queue(disk->queue);
        blk_integrity_unregister(disk);
@@ -1424,10 +1429,9 @@ static void nvme_update_disk_info(struct gendisk *disk,
                nvme_init_integrity(disk, ns->ms, ns->pi_type);
        if (ns->ms && !nvme_ns_has_pi(ns) && !blk_get_integrity(disk))
                capacity = 0;
-       set_capacity(disk, capacity);
 
-       if (ns->ctrl->oncs & NVME_CTRL_ONCS_DSM)
-               nvme_config_discard(ns->ctrl, stream_alignment, disk->queue);
+       set_capacity(disk, capacity);
+       nvme_config_discard(ns);
        blk_mq_unfreeze_queue(disk->queue);
 }