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[PATCH] libata-hp-prep: make some ata_device fields persistent

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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>
This commit is contained in:
Tejun Heo 2006-05-31 18:27:32 +09:00
parent 3ef3b43d56
commit 72fa4b742b
2 changed files with 22 additions and 5 deletions
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14
drivers/scsi/libata-core.c
View File

@ -5153,9 +5153,18 @@ static void ata_host_remove(struct ata_port *ap, unsigned int do_unregister)
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 @@ static void ata_host_init(struct ata_port *ap, struct Scsi_Host *host,
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);
}

13
include/linux/libata.h
View File

@ -130,6 +130,7 @@ enum {
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_ering {
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_device {
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 */