| Message ID | 1660749608-62897-1-git-send-email-john.garry@huawei.com |
|---|---|
| State | New |
| Headers | show |
| Series | [RFT] ata: libata: Set __ATA_BASE_SHT max_sectors | expand |
diff --git a/include/linux/libata.h b/include/linux/libata.h index 0269ff114f5a..698032e5ef2d 100644 --- a/include/linux/libata.h +++ b/include/linux/libata.h @@ -1382,7 +1382,8 @@ extern const struct attribute_group *ata_common_sdev_groups[]; .proc_name = drv_name, \ .slave_destroy = ata_scsi_slave_destroy, \ .bios_param = ata_std_bios_param, \ - .unlock_native_capacity = ata_scsi_unlock_native_capacity + .unlock_native_capacity = ata_scsi_unlock_native_capacity,\ + .max_sectors = ATA_MAX_SECTORS_LBA48 #define ATA_SUBBASE_SHT(drv_name) \ __ATA_BASE_SHT(drv_name), \
Commit 0568e6122574 ("ata: libata-scsi: cap ata_device->max_sectors according to shost->max_sectors") inadvertently capped the max_sectors value for some SATA disks to a value which is lower than we would want. For a device which supports LBA48, we would previously have request queue max_sectors_kb and max_hw_sectors_kb values of 1280 and 32767 respectively. For AHCI controllers, the value chosen for shost max sectors comes from the minimum of the SCSI host default max sectors in SCSI_DEFAULT_MAX_SECTORS (1024) and the shost DMA device mapping limit. This means that we would now set the max_sectors_kb and max_hw_sectors_kb values for a disk which supports LBA48 at 512, ignoring DMA mapping limit. As report by Oliver at [0], this caused a performance regression. Fix by picking a large enough max sectors value for ATA host controllers such that we don't needlessly reduce max_sectors_kb for LBA48 disks. [0] https://lore.kernel.org/linux-ide/YvsGbidf3na5FpGb@xsang-OptiPlex-9020/T/#m22d9fc5ad15af66066dd9fecf3d50f1b1ef11da3 Fixes: 0568e6122574 ("ata: libata-scsi: cap ata_device->max_sectors according to shost->max_sectors") Reported-by: Oliver Sang <oliver.sang@intel.com> Signed-off-by: John Garry <john.garry@huawei.com>