libata: improve EH retry delay handling

EH retries were delayed by 5 seconds to ensure that resets don't occur
back-to-back.  However, this 5 second delay is superflous or excessive
in many cases.  For example, after IDENTIFY times out, there's no
reason to wait five more seconds before retrying.

This patch adds ehc->last_reset timestamp and record the timestamp for
the last reset trial or success and uses it to space resets by
ATA_EH_RESET_COOL_DOWN which is 5 secs and removes unconditional 5 sec
sleeps.

As this change makes inter-try waits often shorter and they're
redundant in nature, this patch also removes the "retrying..."
messages.

While at it, convert explicit rounding up division to DIV_ROUND_UP().

This change speeds up EH in many cases w/o sacrificing robustness.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 0 insertions, 10 deletions

diff --git a/drivers/ata/libata-pmp.c b/drivers/ata/libata-pmp.c
index 63691d77ac43..b65db309c181 100644
--- a/drivers/ata/libata-pmp.c
+++ b/drivers/ata/libata-pmp.c
@@ -727,19 +727,12 @@ static int sata_pmp_eh_recover_pmp(struct ata_port *ap,
                 }
 
                 if (tries) {
-                        int sleep = ehc->i.flags & ATA_EHI_DID_RESET;
-
                         /* consecutive revalidation failures? speed down */
                         if (reval_failed)
                                 sata_down_spd_limit(link);
                         else
                                 reval_failed = 1;
 
-                        ata_dev_printk(dev, KERN_WARNING,
-                                       "retrying reset%s\n",
-                                       sleep ? " in 5 secs" : "");
-                        if (sleep)
-                                ssleep(5);
                         ehc->i.action |= ATA_EH_RESET;
                         goto retry;
                 } else {
@@ -991,10 +984,7 @@ static int sata_pmp_eh_recover(struct ata_port *ap)
                 goto retry;
 
         if (--pmp_tries) {
-                ata_port_printk(ap, KERN_WARNING,
-                                "failed to recover PMP, retrying in 5 secs\n");
                 pmp_ehc->i.action |= ATA_EH_RESET;
-                ssleep(5);
                 goto retry;
         }