Re: [PATCH v4] libata: Add ATA_HORKAGE_NO_NCQ_ON_AMD for Samsung 860 and 870 SSD.

Damien Le Moal
2021-09-01T05:47:55Z

On 2021/09/01 13:52, Kate Hsuan wrote:
> Many users are reporting that the Samsung 860 and 870 SSD are having
> various issues when combined with AMD SATA controllers and only
> completely disabling NCQ helps to avoid these issues.
>
> Always disabling NCQ for Samsung 860/870 SSDs regardless of the host
> SATA adapter vendor will cause I/O performance degradation with well
> behaved adapters. To limit the performance impact to AMD adapters,
> introduce the ATA_HORKAGE_NO_NCQ_ON_AMD flag to force disable NCQ
> only for these adapters.
>
> BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=201693
> Signed-off-by: Kate Hsuan <hpa@redhat.com>
> ---
> Changes in v4:
> * A function ata_dev_check_adapter() is added to check the vendor ID of
> the adapter.
> * ATA_HORKAGE_NONCQ_ON_AMD was modified to ATA_HORKAGE_NO_NCQ_ON_AMD to
> align with the naming??convention.
> * Commit messages were improved according??to reviewer comments.
>
> Changes in v3:
> * ATA_HORKAGE_NONCQ_ON_ASMEDIA_AMD_MARVELL was modified to
> ATA_HORKAGE_NONCQ_ON_AMD.
> * Codes were fixed to completely disable NCQ on AMD controller.
>
> ---
> drivers/ata/libata-core.c | 32 ++++++++++++++++++++++++++++++--
> include/linux/libata.h | 1 +
> 2 files changed, 31 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
> index c861c93d1e84..49049cd713e4 100644
> --- a/drivers/ata/libata-core.c
> +++ b/drivers/ata/libata-core.c
> @@ -2186,6 +2186,25 @@ static void ata_dev_config_ncq_prio(struct ata_device *dev)
> dev->flags &= ~ATA_DFLAG_NCQ_PRIO;
> }
>
> +static bool ata_dev_check_adapter(struct ata_device *dev,
> + unsigned short vendor_id)
> +{
> + struct pci_dev *pcidev = NULL;
> + struct device *parent_dev = NULL;
> +
> + for (parent_dev = dev->tdev.parent; parent_dev != NULL;
> + parent_dev = parent_dev->parent) {
> + if (dev_is_pci(parent_dev)) {
> + pcidev = to_pci_dev(parent_dev);
> + if (pcidev->vendor == vendor_id)
> + return true;
> + break;
> + }
> + }
> +
> + return false;
> +}
> +
> static int ata_dev_config_ncq(struct ata_device *dev,
> char *desc, size_t desc_sz)
> {
> @@ -2204,6 +2223,13 @@ static int ata_dev_config_ncq(struct ata_device *dev,
> snprintf(desc, desc_sz, "NCQ (not used)");
> return 0;
> }
> +
> + if (dev->horkage & ATA_HORKAGE_NO_NCQ_ON_AMD &&
> + ata_dev_check_adapter(dev, PCI_VENDOR_ID_AMD)) {
> + snprintf(desc, desc_sz, "NCQ (not used)");
> + return 0;
> + }
> +
> if (ap->flags & ATA_FLAG_NCQ) {
> hdepth = min(ap->scsi_host->can_queue, ATA_MAX_QUEUE);
> dev->flags |= ATA_DFLAG_NCQ;
> @@ -3971,9 +3997,11 @@ static const struct ata_blacklist_entry ata_device_blacklist [] = {
> { "Samsung SSD 850*", NULL, ATA_HORKAGE_NO_NCQ_TRIM |
> ATA_HORKAGE_ZERO_AFTER_TRIM, },
> { "Samsung SSD 860*", NULL, ATA_HORKAGE_NO_NCQ_TRIM |
> - ATA_HORKAGE_ZERO_AFTER_TRIM, },
> + ATA_HORKAGE_ZERO_AFTER_TRIM |
> + ATA_HORKAGE_NO_NCQ_ON_AMD, },
> { "Samsung SSD 870*", NULL, ATA_HORKAGE_NO_NCQ_TRIM |
> - ATA_HORKAGE_ZERO_AFTER_TRIM, },
> + ATA_HORKAGE_ZERO_AFTER_TRIM |
> + ATA_HORKAGE_NO_NCQ_ON_AMD, },
> { "FCCT*M500*", NULL, ATA_HORKAGE_NO_NCQ_TRIM |
> ATA_HORKAGE_ZERO_AFTER_TRIM, },
>
> diff --git a/include/linux/libata.h b/include/linux/libata.h
> index 860e63f5667b..cdc248a15763 100644
> --- a/include/linux/libata.h
> +++ b/include/linux/libata.h
> @@ -426,6 +426,7 @@ enum {
> ATA_HORKAGE_NOTRIM = (1 << 24), /* don't use TRIM */
> ATA_HORKAGE_MAX_SEC_1024 = (1 << 25), /* Limit max sects to 1024 */
> ATA_HORKAGE_MAX_TRIM_128M = (1 << 26), /* Limit max trim size to 128M */
> + ATA_HORKAGE_NO_NCQ_ON_AMD = (1 << 27), /* Disable NCQ on AMD chipset */
>
> /* DMA mask for user DMA control: User visible values; DO NOT
> renumber */
> --
> 2.31.1
>
>

Looks good to me.

Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>

--
Damien Le Moal
Western Digital Research