From: Xiang Chen chenxiang66@hisilicon.com
Max sectors of limitations for scsi host can be set through scsi_host_template->max_sectors in scsi driver. But we find that max sectors may exceed scsi_host_template->max_sectors for SATA disk even if we set it. We find that it may be overwrote in some scsi drivers (which calls the callback slave_configure and also calls function ata_scsi_dev_config in it). The invoking relationship is as follows:
scsi_probe_and_add_lun ... scsi_alloc_sdev scsi_mq_alloc_queue ... __scsi_init_queue blk_queue_max_hw_sectors(q, shost->max_sectors) //max_sectors coming from sht->max_sectors scsi_change_queue_depth scsi_sysfs_device_initialize shost->hostt->slave_alloc() xxx_salve_configure ... ata_scsi_dev_config blk_queue_max_hw_sectors(q, dev->max_sectors) //max_sectors is overwrote by dev->max_sectors
To avoid the issue, set q->limits.max_sectors with the minimum value between dev->max_sectors and q->limits.max_sectors.
Signed-off-by: Xiang Chen chenxiang66@hisilicon.com --- drivers/ata/libata-scsi.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c index 48b8934..fb7b243 100644 --- a/drivers/ata/libata-scsi.c +++ b/drivers/ata/libata-scsi.c @@ -1026,12 +1026,15 @@ EXPORT_SYMBOL_GPL(ata_scsi_dma_need_drain); int ata_scsi_dev_config(struct scsi_device *sdev, struct ata_device *dev) { struct request_queue *q = sdev->request_queue; + unsigned int max_sectors;
if (!ata_id_has_unload(dev->id)) dev->flags |= ATA_DFLAG_NO_UNLOAD;
/* configure max sectors */ - blk_queue_max_hw_sectors(q, dev->max_sectors); + max_sectors = min_t(unsigned int, dev->max_sectors, + q->limits.max_sectors); + blk_queue_max_hw_sectors(q, max_sectors);
if (dev->class == ATA_DEV_ATAPI) { sdev->sector_size = ATA_SECT_SIZE;