3 files changed, 13 insertions, 0 deletions

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 7f701cbe14ab..96039671e3b9 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -2660,6 +2660,9 @@ static int ahci_init_one(struct pci_dev *pdev, const struct pci_device_id *ent)
         host->iomap = pcim_iomap_table(pdev);
         host->private_data = hpriv;
 
+        if (!(hpriv->cap & HOST_CAP_SSS))
+                host->flags |= ATA_HOST_PARALLEL_SCAN;
+
         if (pi.flags & ATA_FLAG_EM)
                 ahci_reset_em(host);
 
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index c507a9ac78f4..f810078fafcc 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -5920,6 +5920,15 @@ static void async_port_probe(void *data, async_cookie_t cookie)
 {
         int rc;
         struct ata_port *ap = data;
+
+        /*
+         * If we're not allowed to scan this host in parallel,
+         * we need to wait until all previous scans have completed
+         * before going further.
+         */
+        if (!(ap->host->flags & ATA_HOST_PARALLEL_SCAN))
+                async_synchronize_cookie(cookie);
+
         /* probe */
         if (ap->ops->error_handler) {
                 struct ata_eh_info *ehi = &ap->link.eh_info;
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 4f7c8fb4d3fe..b6b8a7f3ec66 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -239,6 +239,7 @@ enum {
         /* host set flags */
         ATA_HOST_SIMPLEX        = (1 << 0),     /* Host is simplex, one DMA channel per host only */
         ATA_HOST_STARTED        = (1 << 1),     /* Host started */
+        ATA_HOST_PARALLEL_SCAN  = (1 << 2),     /* Ports on this host can be scanned in parallel */
 
         /* bits 24:31 of host->flags are reserved for LLD specific flags */