Implement EH helper function ata_eh_autopsy(). This function analyzes
how the port and qc failed and determine what to do to recover from
the condition.
* Analyzes TF/SError
* Record the error and determine whether speeding down is necessary.
If so, adjust relevant limits.
* Determine which action is required to recover - REVALIDATE,
PORT_SOFTRESET or PORT_HARDRESET.
Signed-off-by: Tejun Heo <htejun@xxxxxxxxx>
---
drivers/scsi/libata-core.c | 1
drivers/scsi/libata-eh.c | 280 ++++++++++++++++++++++++++++++++++++++++++++
include/linux/libata.h | 3
3 files changed, 284 insertions(+), 0 deletions(-)
166600385563ff9043f86179422b041fb6a1c7fb
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 06bf7f4..ea5335b 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -5280,3 +5280,4 @@ EXPORT_SYMBOL_GPL(ata_eh_schedule_port);
EXPORT_SYMBOL_GPL(ata_eh_qc_complete);
EXPORT_SYMBOL_GPL(ata_eh_qc_retry);
EXPORT_SYMBOL_GPL(ata_eh_determine_qc);
+EXPORT_SYMBOL_GPL(ata_eh_autopsy);
diff --git a/drivers/scsi/libata-eh.c b/drivers/scsi/libata-eh.c
index 7781f67..5224fe4 100644
--- a/drivers/scsi/libata-eh.c
+++ b/drivers/scsi/libata-eh.c
@@ -550,3 +550,283 @@ struct ata_queued_cmd * ata_eh_determine
return __ata_qc_from_tag(ap, ap->active_tag);
}
+/**
+ * ata_eh_analyze_tf - analyze taskfile of a failed qc
+ * @qc: qc to analyze
+ * @tf: Taskfile registers to analyze
+ *
+ * Analyze taskfile of @qc and further determine cause of
+ * failure. This function also requests ATAPI sense data if
+ * avaliable.
+ *
+ * LOCKING:
+ * Kernel thread context (may sleep)
+ *
+ * RETURNS:
+ * Determined recovery action
+ */
+static unsigned int ata_eh_analyze_tf(struct ata_queued_cmd *qc,
+ const struct ata_taskfile *tf)
+{
+ unsigned int tmp, action = 0;
+ u8 stat = tf->command, err = tf->feature;
+
+ if ((stat & (ATA_BUSY | ATA_DRQ | ATA_DRDY)) != ATA_DRDY) {
+ qc->err_mask |= AC_ERR_HSM;
+ return ATA_PORT_SOFTRESET;
+ }
+
+ if (!(qc->err_mask & AC_ERR_DEV))
+ return 0;
+
+ switch (qc->dev->class) {
+ case ATA_DEV_ATA:
+ if (err & ATA_ICRC)
+ qc->err_mask |= AC_ERR_ATA_BUS;
+ if (err & ATA_UNC)
+ qc->err_mask |= AC_ERR_MEDIA;
+ if (err & ATA_IDNF)
+ qc->err_mask |= AC_ERR_INVALID;
+ break;
+
+ case ATA_DEV_ATAPI:
+ tmp = atapi_eh_request_sense(qc->ap, qc->dev,
+ qc->scsicmd->sense_buffer);
+ if (!tmp) {
+ /*
+ * ATA_QCFLAG_SENSE_VALID is used to tell
+ * atapi_qc_complete() that sense data is
+ * already valid.
+ *
+ * TODO: interpret sense data and set
+ * appropriate err_mask.
+ */
+ qc->err_mask &= ~AC_ERR_DEV;
+ qc->flags |= ATA_QCFLAG_SENSE_VALID;
+ } else
+ qc->err_mask |= tmp;
+ }
+
+ if (qc->err_mask) {
+ action |= ATA_PORT_REVALIDATE;
+ if (qc->err_mask &
+ (AC_ERR_HSM | AC_ERR_TIMEOUT | AC_ERR_ATA_BUS))
+ action |= ATA_PORT_SOFTRESET;
+ }
+
+ return action;
+}
+
+/**
+ * ata_eh_analyze_serror - analyze SError of a failed qc
+ * @serror: SError to analyze
+ * @p_err_mask: Resulting err_mask
+ *
+ * Analyze SError if available and further determine cause of
+ * failure.
+ *
+ * LOCKING:
+ * None.
+ *
+ * RETURNS:
+ * Determined recovery action
+ */
+static unsigned int ata_eh_analyze_serror(u32 serror, unsigned int *p_err_mask)
+{
+ unsigned int action = 0;
+
+ /* read SError and clear it */
+ if (serror & SERR_PERSISTENT) {
+ *p_err_mask |= AC_ERR_ATA_BUS;
+ action |= ATA_PORT_HARDRESET;
+ }
+ if (serror &
+ (SERR_DATA_RECOVERED | SERR_COMM_RECOVERED | SERR_DATA)) {
+ *p_err_mask |= AC_ERR_ATA_BUS;
+ action |= ATA_PORT_SOFTRESET;
+ }
+ if (serror & SERR_PROTOCOL) {
+ *p_err_mask |= AC_ERR_HSM;
+ action |= ATA_PORT_SOFTRESET;
+ }
+ if (serror & SERR_INTERNAL) {
+ *p_err_mask |= AC_ERR_SYSTEM;
+ action |= ATA_PORT_SOFTRESET;
+ }
+
+ return action;
+}
+
+static int ata_eh_categorize_ering_entry(struct ata_ering_entry *ent)
+{
+ if (ent->err_mask & (AC_ERR_ATA_BUS | AC_ERR_TIMEOUT))
+ return 1;
+
+ if (ent->is_io) {
+ if (ent->err_mask & AC_ERR_HSM)
+ return 1;
+ if ((ent->err_mask &
+ (AC_ERR_DEV|AC_ERR_MEDIA|AC_ERR_INVALID)) == AC_ERR_DEV)
+ return 2;
+ }
+
+ return 0;
+}
+
+struct speed_down_needed_arg {
+ u64 since;
+ int nr_errors[3];
+};
+
+static int speed_down_needed_cb(struct ata_ering_entry *ent, void *void_arg)
+{
+ struct speed_down_needed_arg *arg = void_arg;
+
+ if (ent->timestamp < arg->since)
+ return -1;
+
+ arg->nr_errors[ata_eh_categorize_ering_entry(ent)]++;
+ return 0;
+}
+
+/**
+ * ata_eh_speed_down_needed - Determine wheter speed down is necessary
+ * @dev: Device of interest
+ *
+ * This function examines error ring of @dev and determines
+ * whether speed down is necessary. Speed down is necessary if
+ * there have been more than 3 of CAT-1 errors or 10 of Cat-2
+ * errors during last 15 minutes.
+ *
+ * Cat-1 errors are ATA_BUS, TIMEOUT for any command and HSM
+ * violation for known supported commands.
+ *
+ * Cat-2 errors are unclassified DEV error for known supported
+ * command.
+ *
+ * LOCKING:
+ * Inherited from caller.
+ *
+ * RETURNS:
+ * 1 if speed down is necessary, 0 otherwise
+ */
+static int ata_eh_speed_down_needed(struct ata_device *dev)
+{
+ const u64 interval = 15LLU * 60 * HZ;
+ static const int err_limits[3] = { -1, 3, 10 };
+ struct speed_down_needed_arg arg;
+ struct ata_ering_entry *ent;
+ int err_cat;
+ u64 j64;
+
+ ent = ata_ering_top(&dev->ering);
+ if (!ent)
+ return 0;
+
+ err_cat = ata_eh_categorize_ering_entry(ent);
+ if (err_cat == 0)
+ return 0;
+
+ memset(&arg, 0, sizeof(arg));
+
+ j64 = get_jiffies_64();
+ if (j64 >= interval)
+ arg.since = j64 - interval;
+ else
+ arg.since = 0;
+
+ ata_ering_map(&dev->ering, speed_down_needed_cb, &arg);
+
+ return arg.nr_errors[err_cat] > err_limits[err_cat];
+}
+
+/**
+ * ata_eh_speed_down - record error and speed down if necessary
+ * @ap: Host port failed device lives on
+ * @dev: Failed device
+ * @is_io: Did the device fail during normal IO?
+ * @err_mask: err_mask of the error
+ *
+ * Record error and examine error history to determine whether
+ * adjusting transmission speed is necessary. It also sets
+ * transmission limits appropriately if such adjustment is
+ * necessary.
+ *
+ * LOCKING:
+ * Kernel thread context (may sleep)
+ *
+ * RETURNS:
+ * 0 on success, -errno otherwise
+ */
+static int ata_eh_speed_down(struct ata_port *ap, struct ata_device *dev,
+ int is_io, unsigned int err_mask)
+{
+ if (!err_mask)
+ return 0;
+
+ /* record error and determine whether speed down is necessary */
+ ata_ering_record(&dev->ering, is_io, err_mask);
+
+ if (!ata_eh_speed_down_needed(dev))
+ return 0;
+
+ /* speed down SATA link speed if possible */
+ if (ata_down_sata_spd_limit(ap) == 0)
+ return ATA_PORT_HARDRESET;
+
+ /* lower transfer mode */
+ if (ata_down_xfermask_limit(ap, dev, 0) == 0)
+ return ATA_PORT_SOFTRESET;
+
+ printk(KERN_ERR "ata%u: dev %u speed down requested but no "
+ "transfer mode left\n", ap->id, dev->devno);
+ return 0;
+}
+
+/**
+ * ata_eh_autopsy - analyze error and determine recovery action
+ * @ap: host port to perform autopsy on
+ * @qc: failed command
+ * @tf: taskfile registers to analyze
+ * @serror: SError value to analyze
+ *
+ * Analyze why @qc failed and determine which recovery action is
+ * needed. This function also sets more detailed AC_ERR_* values
+ * and fills sense data for ATAPI CHECK SENSE.
+ *
+ * LOCKING:
+ * Kernel thread context (may sleep)
+ *
+ * RETURNS:
+ * Determined recovery action
+ */
+unsigned int ata_eh_autopsy(struct ata_port *ap, struct ata_queued_cmd *qc,
+ const struct ata_taskfile *tf, u32 serror)
+{
+ unsigned int action = 0;
+
+ if (ap->flags & ATA_FLAG_FROZEN)
+ action |= ATA_PORT_SOFTRESET;
+
+ if (!qc)
+ return action;
+
+ if (qc->err_mask & AC_ERR_TIMEOUT)
+ action |= ATA_PORT_SOFTRESET;
+
+ /* determine cause of failure. */
+ action |= ata_eh_analyze_tf(qc, tf);
+ action |= ata_eh_analyze_serror(serror, &qc->err_mask);
+ action |= ata_eh_speed_down(ap, qc->dev, qc->flags & ATA_QCFLAG_IO,
+ qc->err_mask);
+
+ /* DEV errors are probably spurious in case of ATA_BUS error */
+ if (qc->err_mask & AC_ERR_ATA_BUS)
+ qc->err_mask &= ~(AC_ERR_DEV | AC_ERR_MEDIA | AC_ERR_INVALID);
+
+ if (qc->err_mask)
+ action |= ATA_PORT_REVALIDATE;
+
+ return action;
+}
+
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 789dd75..f65bde5 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -686,6 +686,9 @@ extern void ata_eh_qc_complete(struct at
extern void ata_eh_qc_retry(struct ata_queued_cmd *qc);
extern struct ata_queued_cmd * ata_eh_determine_qc(struct ata_port *ap,
struct ata_taskfile *tf);
+extern unsigned int ata_eh_autopsy(struct ata_port *ap,
+ struct ata_queued_cmd *qc,
+ const struct ata_taskfile *tf, u32 serror);
static inline int
--
1.2.4
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