[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/include/linux/libata.h b/include/linux/libata.h
index d4a668c..aa14eda 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -130,6 +130,7 @@
ATA_DFLAG_CFG_MASK = (1 << 8) - 1,
ATA_DFLAG_PIO = (1 << 8), /* device currently in PIO mode */
+ ATA_DFLAG_INIT_MASK = (1 << 16) - 1,
ATA_DFLAG_DETACH = (1 << 16),
ATA_DFLAG_DETACHED = (1 << 17),
@@ -410,10 +411,11 @@
struct ata_device {
struct ata_port *ap;
- 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 */
+ unsigned long flags; /* ATA_DFLAG_xxx */
+ /* n_sector is used as CLEAR_OFFSET, read comment above CLEAR_OFFSET */
+ u64 n_sectors; /* size of device, if ATA */
+ unsigned int class; /* ATA_DEV_xxx */
u16 id[ATA_ID_WORDS]; /* IDENTIFY xxx DEVICE data */
u8 pio_mode;
u8 dma_mode;
@@ -439,6 +441,11 @@
struct ata_ering ering;
};
+/* Offset into struct ata_device. Fields above it are maintained
+ * acress device init. Fields below are zeroed.
+ */
+#define ATA_DEVICE_CLEAR_OFFSET offsetof(struct ata_device, n_sectors)
+
struct ata_eh_info {
struct ata_device *dev; /* offending device */
u32 serror; /* SError from LLDD */