From 99cf610aa4840d822cdc67d194b23b55010ca9bd Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 29 Jan 2009 20:31:32 +0900 Subject: libata: clear dev->ering in smarter way dev->ering used to be cleared together with the rest of ata_device in ata_dev_init() which is called whenever a probing event occurs. dev->ering is about to be used to track probing failures so it needs to remain persistent over multiple porbing events. This patch achieves this by doing the following. * Instead of CLEAR_OFFSET, define CLEAR_BEGIN and CLEAR_END and only clear between BEGIN and END. ering is moved after END. The split of persistent area is to allow hotter items remain at the head. * ering is explicitly cleared on ata_dev_disable() and when device attach succeeds. So, ering is persistent throug a device's life time (unless explicitly cleared of course) and also through periods inbetween disablement of an attached device and successful detection of the next one. Signed-off-by: Tejun Heo Signed-off-by: Jeff Garzik --- include/linux/libata.h | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) (limited to 'include/linux/libata.h') diff --git a/include/linux/libata.h b/include/linux/libata.h index bca3ba25f52a..9dcefee5843c 100644 --- a/include/linux/libata.h +++ b/include/linux/libata.h @@ -580,7 +580,7 @@ struct ata_device { acpi_handle acpi_handle; union acpi_object *gtf_cache; #endif - /* n_sector is used as CLEAR_OFFSET, read comment above CLEAR_OFFSET */ + /* n_sector is CLEAR_BEGIN, read comment above CLEAR_BEGIN */ u64 n_sectors; /* size of device, if ATA */ unsigned int class; /* ATA_DEV_xxx */ unsigned long unpark_deadline; @@ -605,20 +605,22 @@ struct ata_device { u16 heads; /* Number of heads */ u16 sectors; /* Number of sectors per track */ - /* error history */ - int spdn_cnt; - struct ata_ering ering; - union { u16 id[ATA_ID_WORDS]; /* IDENTIFY xxx DEVICE data */ u32 gscr[SATA_PMP_GSCR_DWORDS]; /* PMP GSCR block */ }; + + /* error history */ + int spdn_cnt; + /* ering is CLEAR_END, read comment above CLEAR_END */ + struct ata_ering ering; }; -/* Offset into struct ata_device. Fields above it are maintained - * acress device init. Fields below are zeroed. +/* Fields between ATA_DEVICE_CLEAR_BEGIN and ATA_DEVICE_CLEAR_END are + * cleared to zero on ata_dev_init(). */ -#define ATA_DEVICE_CLEAR_OFFSET offsetof(struct ata_device, n_sectors) +#define ATA_DEVICE_CLEAR_BEGIN offsetof(struct ata_device, n_sectors) +#define ATA_DEVICE_CLEAR_END offsetof(struct ata_device, ering) struct ata_eh_info { struct ata_device *dev; /* offending device */ -- cgit v1.2.2