ata: libata: Set __ATA_BASE_SHT max_sectors
Commit 0568e612 ("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: 0568e612 ("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> Signed-off-by:
Damien Le Moal <damien.lemoal@opensource.wdc.com>
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