Commit 99cf610a authored by Tejun Heo's avatar Tejun Heo Committed by Jeff Garzik
Browse files

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: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarJeff Garzik <jgarzik@redhat.com>
parent 9913ff8a

drivers/ata/libata-core.c

+2 −2
Original line number Diff line number Diff line
@@ -5404,8 +5404,8 @@ void ata_dev_init(struct ata_device *dev) 
	dev->horkage = 0;

	spin_unlock_irqrestore(ap->lock, flags);



	memset((void *)dev + ATA_DEVICE_CLEAR_OFFSET, 0,

	       sizeof(*dev) - ATA_DEVICE_CLEAR_OFFSET);

	memset((void *)dev + ATA_DEVICE_CLEAR_BEGIN, 0,

	       ATA_DEVICE_CLEAR_END - ATA_DEVICE_CLEAR_BEGIN);

	dev->pio_mask = UINT_MAX;

	dev->mwdma_mask = UINT_MAX;

	dev->udma_mask = UINT_MAX;

drivers/ata/libata-eh.c

+7 −0
Original line number Diff line number Diff line
@@ -1194,6 +1194,11 @@ void ata_dev_disable(struct ata_device *dev) 
	ata_acpi_on_disable(dev);

	ata_down_xfermask_limit(dev, ATA_DNXFER_FORCE_PIO0 | ATA_DNXFER_QUIET);

	dev->class++;



	/* From now till the next successful probe, ering is used to

	 * track probe failures.  Clear accumulated device error info.

	 */

	ata_ering_clear(&dev->ering);

}



/**
@@ -2765,6 +2770,8 @@ static int ata_eh_revalidate_and_attach(struct ata_link *link, 
						     readid_flags, dev->id);

			switch (rc) {

			case 0:

				/* clear error info accumulated during probe */

				ata_ering_clear(&dev->ering);

				new_mask |= 1 << dev->devno;

				break;

			case -ENOENT:

include/linux/libata.h

+10 −8
Original line number Diff line number Diff line
@@ -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 */

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