[PATCH] libata: add per-device max_sectors
If a low level driver wants to control max_sectors, it had to adjust
ap->host->max_sectors and set ATA_DFLAG_LOCK_SECTORS to tell
ata_scsi_slave_config not to override the limit. This is not only
cumbersome but also incorrect for hosts which support more than one
devices per port.
This patch adds per-device ->max_sectors. If the field is unset
(zero), libata core layer will adjust ->max_sectors according to
default rules. If the field is set, libata honors the setting.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>
diff --git a/drivers/scsi/libata-scsi.c b/drivers/scsi/libata-scsi.c
index 3628fed..86da465 100644
--- a/drivers/scsi/libata-scsi.c
+++ b/drivers/scsi/libata-scsi.c
@@ -684,23 +684,23 @@
if (sdev->id < ATA_MAX_DEVICES) {
struct ata_port *ap;
struct ata_device *dev;
+ unsigned int max_sectors;
ap = (struct ata_port *) &sdev->host->hostdata[0];
dev = &ap->device[sdev->id];
- /* TODO: 1024 is an arbitrary number, not the
+ /* TODO: 2048 is an arbitrary number, not the
* hardware maximum. This should be increased to
* 65534 when Jens Axboe's patch for dynamically
* determining max_sectors is merged.
*/
- if ((dev->flags & ATA_DFLAG_LBA48) &&
- ((dev->flags & ATA_DFLAG_LOCK_SECTORS) == 0)) {
- /*
- * do not overwrite sdev->host->max_sectors, since
- * other drives on this host may not support LBA48
- */
- blk_queue_max_sectors(sdev->request_queue, 2048);
- }
+ max_sectors = ATA_MAX_SECTORS;
+ if (dev->flags & ATA_DFLAG_LBA48)
+ max_sectors = 2048;
+ if (dev->max_sectors)
+ max_sectors = dev->max_sectors;
+
+ blk_queue_max_sectors(sdev->request_queue, max_sectors);
/*
* SATA DMA transfers must be multiples of 4 byte, so