From 72fa4b742b327bd1b07985d79a61c61dbd9fd4e6 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Wed, 31 May 2006 18:27:32 +0900 Subject: [PATCH] [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 --- drivers/scsi/libata-core.c | 14 ++++++++++++-- include/linux/libata.h | 13 ++++++++++--- 2 files changed, 22 insertions(+), 5 deletions(-) diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c index 8fda8228159c..a07ab77d32d6 100644 --- a/drivers/scsi/libata-core.c +++ b/drivers/scsi/libata-core.c @@ -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); } diff --git a/include/linux/libata.h b/include/linux/libata.h index d4a668cf143b..aa14eda0656c 100644 --- a/include/linux/libata.h +++ b/include/linux/libata.h @@ -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 */