From: Ming Lei ming.lei@redhat.com
[ Upstream commit edb854a3680bacc9ef9b91ec0c5ff6105886f6f3 ]
We currently use ->cmd_per_lun as initial queue depth for setting up the budget_map. Martin Wilck reported that it is common for the queue_depth to be subsequently updated in slave_configure() based on detected hardware characteristics.
As a result, for some drivers, the static host template settings for cmd_per_lun and can_queue won't actually get used in practice. And if the default values are used to allocate the budget_map, memory may be consumed unnecessarily.
Fix the issue by reallocating the budget_map after ->slave_configure() returns. At that time the device queue_depth should accurately reflect what the hardware needs.
Link: https://lore.kernel.org/r/20220127153733.409132-1-ming.lei@redhat.com Cc: Bart Van Assche bvanassche@acm.org Reported-by: Martin Wilck martin.wilck@suse.com Suggested-by: Martin Wilck martin.wilck@suse.com Tested-by: Martin Wilck mwilck@suse.com Reviewed-by: Martin Wilck mwilck@suse.com Reviewed-by: Bart Van Assche bvanassche@acm.org Signed-off-by: Ming Lei ming.lei@redhat.com Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/scsi/scsi_scan.c | 55 ++++++++++++++++++++++++++++++++++++---- 1 file changed, 50 insertions(+), 5 deletions(-)
diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c index 23e1c0acdeaee..d0ce723299bf7 100644 --- a/drivers/scsi/scsi_scan.c +++ b/drivers/scsi/scsi_scan.c @@ -214,6 +214,48 @@ static void scsi_unlock_floptical(struct scsi_device *sdev, SCSI_TIMEOUT, 3, NULL); }
+static int scsi_realloc_sdev_budget_map(struct scsi_device *sdev, + unsigned int depth) +{ + int new_shift = sbitmap_calculate_shift(depth); + bool need_alloc = !sdev->budget_map.map; + bool need_free = false; + int ret; + struct sbitmap sb_backup; + + /* + * realloc if new shift is calculated, which is caused by setting + * up one new default queue depth after calling ->slave_configure + */ + if (!need_alloc && new_shift != sdev->budget_map.shift) + need_alloc = need_free = true; + + if (!need_alloc) + return 0; + + /* + * Request queue has to be frozen for reallocating budget map, + * and here disk isn't added yet, so freezing is pretty fast + */ + if (need_free) { + blk_mq_freeze_queue(sdev->request_queue); + sb_backup = sdev->budget_map; + } + ret = sbitmap_init_node(&sdev->budget_map, + scsi_device_max_queue_depth(sdev), + new_shift, GFP_KERNEL, + sdev->request_queue->node, false, true); + if (need_free) { + if (ret) + sdev->budget_map = sb_backup; + else + sbitmap_free(&sb_backup); + ret = 0; + blk_mq_unfreeze_queue(sdev->request_queue); + } + return ret; +} + /** * scsi_alloc_sdev - allocate and setup a scsi_Device * @starget: which target to allocate a &scsi_device for @@ -306,11 +348,7 @@ static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget, * default device queue depth to figure out sbitmap shift * since we use this queue depth most of times. */ - if (sbitmap_init_node(&sdev->budget_map, - scsi_device_max_queue_depth(sdev), - sbitmap_calculate_shift(depth), - GFP_KERNEL, sdev->request_queue->node, - false, true)) { + if (scsi_realloc_sdev_budget_map(sdev, depth)) { put_device(&starget->dev); kfree(sdev); goto out; @@ -1017,6 +1055,13 @@ static int scsi_add_lun(struct scsi_device *sdev, unsigned char *inq_result, } return SCSI_SCAN_NO_RESPONSE; } + + /* + * The queue_depth is often changed in ->slave_configure. + * Set up budget map again since memory consumption of + * the map depends on actual queue depth. + */ + scsi_realloc_sdev_budget_map(sdev, sdev->queue_depth); }
if (sdev->scsi_level >= SCSI_3)