Commit 3884f7b0 authored by Tejun Heo's avatar Tejun Heo Committed by Jeff Garzik
Browse files

libata: clean up EH speed down implementation 



Clean up EH speed down implementation.

* is_io boolean variable is replaced eflags.  is_io is ATA_EFLAG_IS_IO.

* Error categories now have names.

* Better comments.

* Reorder 5min and 10min rules in ata_eh_speed_down_verdict()

* Use local variable @link to cache @dev->link in ata_eh_speed_down()

These changes are to improve readability and ease further changes.
This patch doesn't introduce any behavior change.

Signed-off-by: default avatarTejun Heo <htejun@gmail.com>
Signed-off-by: default avatarJeff Garzik <jeff@garzik.org>
parent 6f1d1e3a

drivers/ata/libata-eh.c

+73 −44
Original line number Diff line number Diff line
@@ -46,9 +46,20 @@ 
#include "libata.h"



enum {

	/* speed down verdicts */

	ATA_EH_SPDN_NCQ_OFF		= (1 << 0),

	ATA_EH_SPDN_SPEED_DOWN		= (1 << 1),

	ATA_EH_SPDN_FALLBACK_TO_PIO	= (1 << 2),



	/* error flags */

	ATA_EFLAG_IS_IO			= (1 << 0),



	/* error categories */

	ATA_ECAT_NONE			= 0,

	ATA_ECAT_ATA_BUS		= 1,

	ATA_ECAT_TOUT_HSM		= 2,

	ATA_ECAT_UNK_DEV		= 3,

	ATA_ECAT_NR			= 4,

};



/* Waiting in ->prereset can never be reliable.  It's sometimes nice
@@ -218,7 +229,7 @@ void ata_port_pbar_desc(struct ata_port *ap, int bar, ssize_t offset, 


#endif /* CONFIG_PCI */



static void ata_ering_record(struct ata_ering *ering, int is_io,

static void ata_ering_record(struct ata_ering *ering, unsigned int eflags,

			     unsigned int err_mask)

{

	struct ata_ering_entry *ent;
@@ -229,7 +240,7 @@ static void ata_ering_record(struct ata_ering *ering, int is_io, 
	ering->cursor %= ATA_ERING_SIZE;



	ent = &ering->ring[ering->cursor];

	ent->is_io = is_io;

	ent->eflags = eflags;

	ent->err_mask = err_mask;

	ent->timestamp = get_jiffies_64();

}
@@ -1451,20 +1462,20 @@ static unsigned int ata_eh_analyze_tf(struct ata_queued_cmd *qc, 
	return action;

}



static int ata_eh_categorize_error(int is_io, unsigned int err_mask)

static int ata_eh_categorize_error(unsigned int eflags, unsigned int err_mask)

{

	if (err_mask & AC_ERR_ATA_BUS)

		return 1;

		return ATA_ECAT_ATA_BUS;



	if (err_mask & AC_ERR_TIMEOUT)

		return 2;

		return ATA_ECAT_TOUT_HSM;



	if (is_io) {

	if (eflags & ATA_EFLAG_IS_IO) {

		if (err_mask & AC_ERR_HSM)

			return 2;

			return ATA_ECAT_TOUT_HSM;

		if ((err_mask &

		     (AC_ERR_DEV|AC_ERR_MEDIA|AC_ERR_INVALID)) == AC_ERR_DEV)

			return 3;

			return ATA_ECAT_UNK_DEV;

	}



	return 0;
@@ -1472,13 +1483,13 @@ static int ata_eh_categorize_error(int is_io, unsigned int err_mask) 


struct speed_down_verdict_arg {

	u64 since;

	int nr_errors[4];

	int nr_errors[ATA_ECAT_NR];

};



static int speed_down_verdict_cb(struct ata_ering_entry *ent, void *void_arg)

{

	struct speed_down_verdict_arg *arg = void_arg;

	int cat = ata_eh_categorize_error(ent->is_io, ent->err_mask);

	int cat = ata_eh_categorize_error(ent->eflags, ent->err_mask);



	if (ent->timestamp < arg->since)

		return -1;
@@ -1495,22 +1506,33 @@ static int speed_down_verdict_cb(struct ata_ering_entry *ent, void *void_arg) 
 *	whether NCQ needs to be turned off, transfer speed should be

 *	stepped down, or falling back to PIO is necessary.

 *

 *	Cat-1 is ATA_BUS error for any command.

 *	ECAT_ATA_BUS	: ATA_BUS error for any command

 *

 *	ECAT_TOUT_HSM	: TIMEOUT for any command or HSM violation for

 *			  IO commands

 *

 *	ECAT_UNK_DEV	: Unknown DEV error for IO commands

 *

 *	Verdicts are

 *

 *	Cat-2 is TIMEOUT for any command or HSM violation for known

 *	supported commands.

 *	NCQ_OFF		: Turn off NCQ.

 *

 *	Cat-3 is is unclassified DEV error for known supported

 *	command.

 *	SPEED_DOWN	: Speed down transfer speed but don't fall back

 *			  to PIO.

 *

 *	NCQ needs to be turned off if there have been more than 3

 *	Cat-2 + Cat-3 errors during last 10 minutes.

 *	FALLBACK_TO_PIO	: Fall back to PIO.

 *

 *	Speed down is necessary if there have been more than 3 Cat-1 +

 *	Cat-2 errors or 10 Cat-3 errors during last 10 minutes.

 *	Even if multiple verdicts are returned, only one action is

 *	taken per error.  ering is cleared after an action is taken.

 *

 *	Falling back to PIO mode is necessary if there have been more

 *	than 10 Cat-1 + Cat-2 + Cat-3 errors during last 5 minutes.

 *	1. If more than 10 ATA_BUS, TOUT_HSM or UNK_DEV errors

 *	   ocurred during last 5 mins, FALLBACK_TO_PIO

 *

 *	2. If more than 3 TOUT_HSM or UNK_DEV errors occurred

 *	   during last 10 mins, NCQ_OFF.

 *

 *	3. If more than 3 ATA_BUS or TOUT_HSM errors, or more than 10

 *	   UNK_DEV errors occurred during last 10 mins, SPEED_DOWN.

 *

 *	LOCKING:

 *	Inherited from caller.
@@ -1525,23 +1547,29 @@ static unsigned int ata_eh_speed_down_verdict(struct ata_device *dev) 
	struct speed_down_verdict_arg arg;

	unsigned int verdict = 0;



	/* scan past 10 mins of error history */

	/* scan past 5 mins of error history */

	memset(&arg, 0, sizeof(arg));

	arg.since = j64 - min(j64, j10mins);

	arg.since = j64 - min(j64, j5mins);

	ata_ering_map(&dev->ering, speed_down_verdict_cb, &arg);



	if (arg.nr_errors[2] + arg.nr_errors[3] > 3)

		verdict |= ATA_EH_SPDN_NCQ_OFF;

	if (arg.nr_errors[1] + arg.nr_errors[2] > 3 || arg.nr_errors[3] > 10)

		verdict |= ATA_EH_SPDN_SPEED_DOWN;

	if (arg.nr_errors[ATA_ECAT_ATA_BUS] +

	    arg.nr_errors[ATA_ECAT_TOUT_HSM] +

	    arg.nr_errors[ATA_ECAT_UNK_DEV] > 10)

		verdict |= ATA_EH_SPDN_FALLBACK_TO_PIO;



	/* scan past 3 mins of error history */

	/* scan past 10 mins of error history */

	memset(&arg, 0, sizeof(arg));

	arg.since = j64 - min(j64, j5mins);

	arg.since = j64 - min(j64, j10mins);

	ata_ering_map(&dev->ering, speed_down_verdict_cb, &arg);



	if (arg.nr_errors[1] + arg.nr_errors[2] + arg.nr_errors[3] > 10)

		verdict |= ATA_EH_SPDN_FALLBACK_TO_PIO;

	if (arg.nr_errors[ATA_ECAT_TOUT_HSM] +

	    arg.nr_errors[ATA_ECAT_UNK_DEV] > 3)

		verdict |= ATA_EH_SPDN_NCQ_OFF;



	if (arg.nr_errors[ATA_ECAT_ATA_BUS] +

	    arg.nr_errors[ATA_ECAT_TOUT_HSM] > 3 ||

	    arg.nr_errors[ATA_ECAT_UNK_DEV] > 10)

		verdict |= ATA_EH_SPDN_SPEED_DOWN;



	return verdict;

}
@@ -1549,7 +1577,7 @@ static unsigned int ata_eh_speed_down_verdict(struct ata_device *dev) 
/**

 *	ata_eh_speed_down - record error and speed down if necessary

 *	@dev: Failed device

 *	@is_io: Did the device fail during normal IO?

 *	@eflags: mask of ATA_EFLAG_* flags

 *	@err_mask: err_mask of the error

 *

 *	Record error and examine error history to determine whether
@@ -1563,18 +1591,19 @@ static unsigned int ata_eh_speed_down_verdict(struct ata_device *dev) 
 *	RETURNS:

 *	Determined recovery action.

 */

static unsigned int ata_eh_speed_down(struct ata_device *dev, int is_io,

				      unsigned int err_mask)

static unsigned int ata_eh_speed_down(struct ata_device *dev,

				unsigned int eflags, unsigned int err_mask)

{

	struct ata_link *link = dev->link;

	unsigned int verdict;

	unsigned int action = 0;



	/* don't bother if Cat-0 error */

	if (ata_eh_categorize_error(is_io, err_mask) == 0)

	if (ata_eh_categorize_error(eflags, err_mask) == 0)

		return 0;



	/* record error and determine whether speed down is necessary */

	ata_ering_record(&dev->ering, is_io, err_mask);

	ata_ering_record(&dev->ering, eflags, err_mask);

	verdict = ata_eh_speed_down_verdict(dev);



	/* turn off NCQ? */
@@ -1590,7 +1619,7 @@ static unsigned int ata_eh_speed_down(struct ata_device *dev, int is_io, 
	/* speed down? */

	if (verdict & ATA_EH_SPDN_SPEED_DOWN) {

		/* speed down SATA link speed if possible */

		if (sata_down_spd_limit(dev->link) == 0) {

		if (sata_down_spd_limit(link) == 0) {

			action |= ATA_EH_HARDRESET;

			goto done;

		}
@@ -1621,7 +1650,7 @@ static unsigned int ata_eh_speed_down(struct ata_device *dev, int is_io, 
	 * SATA.  Consider it only for PATA.

	 */

	if ((verdict & ATA_EH_SPDN_FALLBACK_TO_PIO) && (dev->spdn_cnt >= 2) &&

	    (dev->link->ap->cbl != ATA_CBL_SATA) &&

	    (link->ap->cbl != ATA_CBL_SATA) &&

	    (dev->xfer_shift != ATA_SHIFT_PIO)) {

		if (ata_down_xfermask_limit(dev, ATA_DNXFER_FORCE_PIO) == 0) {

			dev->spdn_cnt = 0;
@@ -1653,8 +1682,8 @@ static void ata_eh_link_autopsy(struct ata_link *link) 
	struct ata_port *ap = link->ap;

	struct ata_eh_context *ehc = &link->eh_context;

	struct ata_device *dev;

	unsigned int all_err_mask = 0;

	int tag, is_io = 0;

	unsigned int all_err_mask = 0, eflags = 0;

	int tag;

	u32 serror;

	int rc;
@@ -1713,15 +1742,15 @@ static void ata_eh_link_autopsy(struct ata_link *link) 
		ehc->i.dev = qc->dev;

		all_err_mask |= qc->err_mask;

		if (qc->flags & ATA_QCFLAG_IO)

			is_io = 1;

			eflags |= ATA_EFLAG_IS_IO;

	}



	/* enforce default EH actions */

	if (ap->pflags & ATA_PFLAG_FROZEN ||

	    all_err_mask & (AC_ERR_HSM | AC_ERR_TIMEOUT))

		ehc->i.action |= ATA_EH_SOFTRESET;

	else if ((is_io && all_err_mask) ||

		 (!is_io && (all_err_mask & ~AC_ERR_DEV)))

	else if (((eflags & ATA_EFLAG_IS_IO) && all_err_mask) ||

		 (!(eflags & ATA_EFLAG_IS_IO) && (all_err_mask & ~AC_ERR_DEV)))

		ehc->i.action |= ATA_EH_REVALIDATE;



	/* If we have offending qcs and the associated failed device,
@@ -1744,7 +1773,7 @@ static void ata_eh_link_autopsy(struct ata_link *link) 
	    dev = link->device;



	if (dev)

		ehc->i.action |= ata_eh_speed_down(dev, is_io, all_err_mask);

		ehc->i.action |= ata_eh_speed_down(dev, eflags, all_err_mask);



	DPRINTK("EXIT\n");

}

include/linux/libata.h

+1 −1
Original line number Diff line number Diff line
@@ -482,7 +482,7 @@ struct ata_port_stats { 
};



struct ata_ering_entry {

	int			is_io;

	unsigned int		eflags;

	unsigned int		err_mask;

	u64			timestamp;

};

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