libata: always do follow-up SRST if hardreset returned -EAGAIN

As an optimization, follow-up SRST used to be skipped if
classification wasn't requested even when hardreset requested it via
-EAGAIN.  However, some hardresets can't wait for device readiness and
skipping SRST can cause timeout or other failures during revalidation.
Always perform follow-up SRST if hardreset returns -EAGAIN.  This
makes reset paths more predictable and thus less error-prone.

While at it, move hardreset error checking such that it's done right
after hardreset is finished.  This simplifies followup SRST condition
check a bit and makes the reset path easier to modify.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 6 insertions, 14 deletions

diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index c98909ba0b1c..d4dad47b8f17 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -2171,18 +2171,12 @@ static int ata_do_reset(struct ata_link *link, ata_reset_fn_t reset,
 }
 
 static int ata_eh_followup_srst_needed(struct ata_link *link,
-                                       int rc, int classify,
-                                       const unsigned int *classes)
+                                       int rc, const unsigned int *classes)
 {
         if ((link->flags & ATA_LFLAG_NO_SRST) || ata_link_offline(link))
                 return 0;
-        if (rc == -EAGAIN) {
-                if (classify)
-                        return 1;
-                rc = 0;
-        }
-        if (rc != 0)
-                return 0;
+        if (rc == -EAGAIN)
+                return 1;
         if (sata_pmp_supported(link->ap) && ata_is_host_link(link))
                 return 1;
         return 0;
@@ -2309,9 +2303,11 @@ int ata_eh_reset(struct ata_link *link, int classify,
                         ehc->i.flags |= ATA_EHI_DID_SOFTRESET;
 
                 rc = ata_do_reset(link, reset, classes, deadline);
+                if (rc && rc != -EAGAIN)
+                        goto fail;
 
                 if (reset == hardreset &&
-                    ata_eh_followup_srst_needed(link, rc, classify, classes)) {
+                    ata_eh_followup_srst_needed(link, rc, classes)) {
                         /* okay, let's do follow-up softreset */
                         reset = softreset;
 
@@ -2326,10 +2322,6 @@ int ata_eh_reset(struct ata_link *link, int classify,
                         ata_eh_about_to_do(link, NULL, ATA_EH_RESET);
                         rc = ata_do_reset(link, reset, classes, deadline);
                 }
-
-                /* -EAGAIN can happen if we skipped followup SRST */
-                if (rc && rc != -EAGAIN)
-                        goto fail;
         } else {
                 if (verbose)
                         ata_link_printk(link, KERN_INFO, "no reset method "