[PATCH v4 1/3] ata: libata-eh: Remove ata_do_eh()

[Damien Le Moal <dlemoal@kernel.org>]

The only reason for ata_do_eh() to exist is that the two caller sites,
ata_std_error_handler() and ata_sff_error_handler() may pass it a
NULL hardreset operation so that the built-in (generic) hardreset
operation for a driver is ignored if the adapter SCR access is not
available.

However, ata_std_error_handler() and ata_sff_error_handler()
modifications of the hardreset port operation can easily be combined as
they are mutually exclusive. That is, a driver using sata_std_hardreset()
as its hardreset operation cannot use sata_sff_hardreset() and
vice-versa.

With this observation, ata_do_eh() can be removed and its code moved to
ata_std_error_handler(). The condition used to ignore the built-in
hardreset port operation is modified to be the one that was used in
ata_sff_error_handler(). This requires defining a stub for the function
sata_sff_hardreset() to avoid compilation errors when CONFIG_ATA_SFF is
not enabled. Furthermore, instead of modifying the local hardreset
operation definition, set the ATA_LFLAG_NO_HRST link flag to prevent
the use of built-in hardreset methods for ports without a valid scr_read
function. This flag is checked in ata_eh_reset() and if set, the
hardreset method is ignored.

This change simplifies ata_sff_error_handler() as this function now only
needs to call ata_std_error_handler().

No functional changes.

Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
---
 drivers/ata/libata-eh.c  | 48 ++++++++++++----------------------------
 drivers/ata/libata-sff.c | 10 +--------
 include/linux/libata.h   |  9 +++++---
 3 files changed, 21 insertions(+), 46 deletions(-)

diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index 436536112043..30c831e56a7f 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -4067,59 +4067,39 @@ void ata_eh_finish(struct ata_port *ap)
 }
 
 /**
- *	ata_do_eh - do standard error handling
+ *	ata_std_error_handler - standard error handler
  *	@ap: host port to handle error for
  *
- *	@prereset: prereset method (can be NULL)
- *	@softreset: softreset method (can be NULL)
- *	@hardreset: hardreset method (can be NULL)
- *	@postreset: postreset method (can be NULL)
- *
  *	Perform standard error handling sequence.
  *
  *	LOCKING:
  *	Kernel thread context (may sleep).
  */
-void ata_do_eh(struct ata_port *ap, ata_prereset_fn_t prereset,
-	       ata_reset_fn_t softreset, ata_reset_fn_t hardreset,
-	       ata_postreset_fn_t postreset)
+void ata_std_error_handler(struct ata_port *ap)
 {
-	struct ata_device *dev;
+	struct ata_port_operations *ops = ap->ops;
+	struct ata_link *link = &ap->link;
 	int rc;
 
+	/* Ignore built-in hardresets if SCR access is not available */
+	if ((ops->hardreset == sata_std_hardreset ||
+	     ops->hardreset == sata_sff_hardreset) && !sata_scr_valid(link))
+		link->flags |= ATA_LFLAG_NO_HRST;
+
 	ata_eh_autopsy(ap);
 	ata_eh_report(ap);
 
-	rc = ata_eh_recover(ap, prereset, softreset, hardreset, postreset,
-			    NULL);
+	rc = ata_eh_recover(ap, ops->prereset, ops->softreset,
+			    ops->hardreset, ops->postreset, NULL);
 	if (rc) {
-		ata_for_each_dev(dev, &ap->link, ALL)
+		struct ata_device *dev;
+
+		ata_for_each_dev(dev, link, ALL)
 			ata_dev_disable(dev);
 	}
 
 	ata_eh_finish(ap);
 }
-
-/**
- *	ata_std_error_handler - standard error handler
- *	@ap: host port to handle error for
- *
- *	Standard error handler
- *
- *	LOCKING:
- *	Kernel thread context (may sleep).
- */
-void ata_std_error_handler(struct ata_port *ap)
-{
-	struct ata_port_operations *ops = ap->ops;
-	ata_reset_fn_t hardreset = ops->hardreset;
-
-	/* ignore built-in hardreset if SCR access is not available */
-	if (hardreset == sata_std_hardreset && !sata_scr_valid(&ap->link))
-		hardreset = NULL;
-
-	ata_do_eh(ap, ops->prereset, ops->softreset, hardreset, ops->postreset);
-}
 EXPORT_SYMBOL_GPL(ata_std_error_handler);
 
 #ifdef CONFIG_PM
diff --git a/drivers/ata/libata-sff.c b/drivers/ata/libata-sff.c
index 5a46c066abc3..e61f00779e40 100644
--- a/drivers/ata/libata-sff.c
+++ b/drivers/ata/libata-sff.c
@@ -2054,8 +2054,6 @@ EXPORT_SYMBOL_GPL(ata_sff_drain_fifo);
  */
 void ata_sff_error_handler(struct ata_port *ap)
 {
-	ata_reset_fn_t softreset = ap->ops->softreset;
-	ata_reset_fn_t hardreset = ap->ops->hardreset;
 	struct ata_queued_cmd *qc;
 	unsigned long flags;
 
@@ -2077,13 +2075,7 @@ void ata_sff_error_handler(struct ata_port *ap)
 
 	spin_unlock_irqrestore(ap->lock, flags);
 
-	/* ignore built-in hardresets if SCR access is not available */
-	if ((hardreset == sata_std_hardreset ||
-	     hardreset == sata_sff_hardreset) && !sata_scr_valid(&ap->link))
-		hardreset = NULL;
-
-	ata_do_eh(ap, ap->ops->prereset, softreset, hardreset,
-		  ap->ops->postreset);
+	ata_std_error_handler(ap);
 }
 EXPORT_SYMBOL_GPL(ata_sff_error_handler);
 
diff --git a/include/linux/libata.h b/include/linux/libata.h
index d092747be588..cf0b3fff3198 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -1412,9 +1412,6 @@ extern void ata_eh_thaw_port(struct ata_port *ap);
 extern void ata_eh_qc_complete(struct ata_queued_cmd *qc);
 extern void ata_eh_qc_retry(struct ata_queued_cmd *qc);
 
-extern void ata_do_eh(struct ata_port *ap, ata_prereset_fn_t prereset,
-		      ata_reset_fn_t softreset, ata_reset_fn_t hardreset,
-		      ata_postreset_fn_t postreset);
 extern void ata_std_error_handler(struct ata_port *ap);
 extern void ata_std_sched_eh(struct ata_port *ap);
 extern void ata_std_end_eh(struct ata_port *ap);
@@ -2152,6 +2149,12 @@ static inline u8 ata_wait_idle(struct ata_port *ap)
 
 	return status;
 }
+#else /* CONFIG_ATA_SFF */
+static inline int sata_sff_hardreset(struct ata_link *link, unsigned int *class,
+				     unsigned long deadline)
+{
+	return -EOPNOTSUPP;
+}
 #endif /* CONFIG_ATA_SFF */
 
 #endif /* __LINUX_LIBATA_H__ */
-- 
2.50.1