[PATCH] libata-hp-prep: make some ata_device fields persistent
Lifetimes of some fields span over device plugging/unplugging. This
patch moves such persistent fields to the top of ata_device and
separate them with ATA_DEVICE_CLEAR_OFFSET. Fields above the offset
are initialized once during host initializatino while all other fields
are cleared before hotplugging. Currently ->ap, devno and part of
flags are persistent.
Note that flags is partially cleared while holding host_set lock.
This is to synchronize with later warm plug implementation which will
record hotplug request in dev->flags.
Signed-off-by: Tejun Heo <htejun@gmail.com>
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 8fda822..a07ab77 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -5153,9 +5153,18 @@
void ata_dev_init(struct ata_device *dev)
{
struct ata_port *ap = dev->ap;
+ unsigned long flags;
- memset((void *)dev, 0, sizeof(*dev));
- dev->devno = dev - ap->device;
+ /* High bits of dev->flags are used to record warm plug
+ * requests which occur asynchronously. Synchronize using
+ * host_set lock.
+ */
+ spin_lock_irqsave(&ap->host_set->lock, flags);
+ dev->flags &= ~ATA_DFLAG_INIT_MASK;
+ spin_unlock_irqrestore(&ap->host_set->lock, flags);
+
+ memset((void *)dev + ATA_DEVICE_CLEAR_OFFSET, 0,
+ sizeof(*dev) - ATA_DEVICE_CLEAR_OFFSET);
dev->pio_mask = UINT_MAX;
dev->mwdma_mask = UINT_MAX;
dev->udma_mask = UINT_MAX;
@@ -5218,6 +5227,7 @@
for (i = 0; i < ATA_MAX_DEVICES; i++) {
struct ata_device *dev = &ap->device[i];
dev->ap = ap;
+ dev->devno = i;
ata_dev_init(dev);
}