> On 4/12/21 7:55 PM, Changheun Lee wrote: > > Set QUEUE_FLAG_LIMIT_BIO_SIZE queue flag to limit bio max size to > > queue max sectors size for UFS device. > > > > Signed-off-by: Changheun Lee <nanich....@samsung.com> > > --- > > drivers/scsi/scsi_lib.c | 2 ++ > > drivers/scsi/ufs/ufshcd.c | 1 + > > include/scsi/scsi_host.h | 2 ++ > > 3 files changed, 5 insertions(+) > > > > diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c > > index 7d52a11e1b61..73ce6ba7903a 100644 > > --- a/drivers/scsi/scsi_lib.c > > +++ b/drivers/scsi/scsi_lib.c > > @@ -1838,6 +1838,8 @@ void __scsi_init_queue(struct Scsi_Host *shost, > > struct request_queue *q) > > * Devices that require a bigger alignment can increase it later. > > */ > > blk_queue_dma_alignment(q, max(4, dma_get_cache_alignment()) - 1); > > + > > + blk_queue_set_limit_bio_size(q, shost->limit_bio_size); > > } > > EXPORT_SYMBOL_GPL(__scsi_init_queue); > > > > diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c > > index d3d05e997c13..000eb5ab022e 100644 > > --- a/drivers/scsi/ufs/ufshcd.c > > +++ b/drivers/scsi/ufs/ufshcd.c > > @@ -9313,6 +9313,7 @@ int ufshcd_init(struct ufs_hba *hba, void __iomem > > *mmio_base, unsigned int irq) > > host->max_channel = UFSHCD_MAX_CHANNEL; > > host->unique_id = host->host_no; > > host->max_cmd_len = UFS_CDB_SIZE; > > + host->limit_bio_size = true; > > > > hba->max_pwr_info.is_valid = false; > > > > diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h > > index e30fd963b97d..486f61588717 100644 > > --- a/include/scsi/scsi_host.h > > +++ b/include/scsi/scsi_host.h > > @@ -607,6 +607,8 @@ struct Scsi_Host { > > unsigned int max_segment_size; > > unsigned long dma_boundary; > > unsigned long virt_boundary_mask; > > + unsigned int limit_bio_size; > > + > > /* > > * In scsi-mq mode, the number of hardware queues supported by the LLD. > > * > > This patch should have been split into one patch for the SCSI core and > another patch for the UFS driver. > > I see an issue with this patch: a new attribute has been introduced in > struct Scsi_Host but it is not used by the SCSI core. That seems weird > to me. > > Another comment I have about this patch is why to restrict the BIO size > (blk_queue_set_limit_bio_size(q, shost->limit_bio_size)) only for UFS > devices? Aren't all block devices, including NVMe devices, expected to > benefit from limiting the BIO size if no stacking is involved? How about > the following approach? > * In blk_queue_max_hw_sectors(), set the maximum BIO size to > max_hw_sectors. As you may know blk_queue_max_hw_sectors() may be > called by any block driver (stacking and non-stacking). > * In blk_stack_limits(), set the maximum BIO size to UINT_MAX. Stacking > block drivers must call blk_stack_limits().
I think it will be good for all block device too, but it might be not in some environment. I got a feedback about it. So I specified to UFS only. I see what you said. I'll try as your approach. > > Thanks, > > Bart. Thanks, Changheun Lee.