Re: [PATCH 3/4] scsi: core: Cap shost max_sectors according to DMA optimum mapping limits

2022-05-23 Thread John Garry via iommu
On 23/05/2022 12:08, Dan Carpenter wrote: Thanks for the report 50b6cb3516365c Dexuan Cui2021-10-07 224/* Use min_t(int, ...) in case shost->can_queue exceeds SHRT_MAX */ 50b6cb3516365c Dexuan Cui2021-10-07 225shost->cmd_per_lun = min_t(int,

Re: [PATCH 3/4] scsi: core: Cap shost max_sectors according to DMA optimum mapping limits

2022-05-23 Thread Dan Carpenter
Hi John, url: https://github.com/intel-lab-lkp/linux/commits/John-Garry/DMA-mapping-changes-for-SCSI-core/20220520-163049 base: https://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu.git next config: s390-randconfig-m031-20220519

Re: [PATCH 3/4] scsi: core: Cap shost max_sectors according to DMA optimum mapping limits

2022-05-23 Thread Damien Le Moal via iommu
On 2022/05/23 15:53, John Garry wrote: > On 21/05/2022 00:30, Damien Le Moal wrote: >>> diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c >>> index f69b77cbf538..a3ae6345473b 100644 >>> --- a/drivers/scsi/hosts.c >>> +++ b/drivers/scsi/hosts.c >>> @@ -225,6 +225,11 @@ int

Re: [PATCH 3/4] scsi: core: Cap shost max_sectors according to DMA optimum mapping limits

2022-05-23 Thread John Garry via iommu
On 21/05/2022 00:30, Damien Le Moal wrote: diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c index f69b77cbf538..a3ae6345473b 100644 --- a/drivers/scsi/hosts.c +++ b/drivers/scsi/hosts.c @@ -225,6 +225,11 @@ int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,

Re: [PATCH 3/4] scsi: core: Cap shost max_sectors according to DMA optimum mapping limits

2022-05-20 Thread Damien Le Moal via iommu
On 5/20/22 17:23, John Garry wrote: > Streaming DMA mappings may be considerably slower when mappings go through > an IOMMU and the total mapping length is somewhat long. This is because the > IOMMU IOVA code allocates and free an IOVA for each mapping, which may > affect performance. > > For

[PATCH 3/4] scsi: core: Cap shost max_sectors according to DMA optimum mapping limits

2022-05-20 Thread John Garry via iommu
Streaming DMA mappings may be considerably slower when mappings go through an IOMMU and the total mapping length is somewhat long. This is because the IOMMU IOVA code allocates and free an IOVA for each mapping, which may affect performance. For performance reasons set the request_queue