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 only dev->devno is
persistent.
Signed-off-by: Tejun Heo <htejun@xxxxxxxxx>
---
drivers/scsi/libata-core.c | 2 +-
include/linux/libata.h | 5 ++++-
2 files changed, 5 insertions(+), 2 deletions(-)
9160b11ebb15ef4f9501a1aba807ed221ef713ed
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 1378b6f..3406f3d 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -1446,7 +1446,6 @@ static void ata_dev_init(struct ata_port
{
memset((void *)dev + ATA_DEVICE_CLEAR_OFFSET, 0,
sizeof(*dev) - ATA_DEVICE_CLEAR_OFFSET);
- dev->devno = dev - ap->device;
dev->pio_mask = UINT_MAX;
dev->mwdma_mask = UINT_MAX;
dev->udma_mask = UINT_MAX;
@@ -4885,6 +4884,7 @@ static void ata_host_init(struct ata_por
for (i = 0; i < ATA_MAX_DEVICES; i++) {
struct ata_device *dev = &ap->device[i];
+ dev->devno = i;
ata_dev_init(ap, dev);
}
diff --git a/include/linux/libata.h b/include/linux/libata.h
index e86d63c..809f3b9 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -395,10 +395,11 @@ struct ata_ering {
struct ata_ering_entry name_entries[size];
struct ata_device {
+ unsigned int devno; /* 0 or 1 */
+ /* fields above n_sectors are not cleared across device init */
u64 n_sectors; /* size of device, if ATA */
unsigned long flags; /* ATA_DFLAG_xxx */
unsigned int class; /* ATA_DEV_xxx */
- unsigned int devno; /* 0 or 1 */
u16 *id; /* IDENTIFY xxx DEVICE data */
u8 pio_mode;
u8 dma_mode;
@@ -423,6 +424,8 @@ struct ata_device {
DEFINE_ATA_ERING (ering, ATA_DEV_ERING_SIZE);
};
+#define ATA_DEVICE_CLEAR_OFFSET offsetof(struct ata_device, n_sectors)
+
struct ata_port {
struct Scsi_Host *host; /* our co-allocated scsi host */
const struct ata_port_operations *ops;
--
1.2.4
-
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