libata: Fix use-after-iounmap

Jens Axboe pointed out that the iounmap() call in libata was occurring
too early, and some drivers (ahci, probably others) were using ioremap'd
memory after it had been unmapped.

The patch should address that problem by way of improving the libata
driver API:

* move ->host_stop() call after all ->port_stop() calls have occurred.

* create default helper function ata_host_stop(), and move iounmap()
call there.

* add ->host_stop_prewalk() hook, use it in sata_qstor.c (hi Mark).
sata_qstor appears to require the host-stop-before-port-stop ordering
that existed prior to applying the attached patch.

14 files changed, 29 insertions, 4 deletions

diff --git a/drivers/scsi/ahci.c b/drivers/scsi/ahci.c
index da5bd33d982d..8b468a628700 100644
--- a/drivers/scsi/ahci.c
+++ b/drivers/scsi/ahci.c
@@ -289,6 +289,8 @@ static void ahci_host_stop(struct ata_host_set *host_set)
 {
         struct ahci_host_priv *hpriv = host_set->private_data;
         kfree(hpriv);
+
+        ata_host_stop(host_set);
 }
 
 static int ahci_port_start(struct ata_port *ap)
diff --git a/drivers/scsi/ata_piix.c b/drivers/scsi/ata_piix.c
index 3867f91ef8c7..54c52349adc5 100644
--- a/drivers/scsi/ata_piix.c
+++ b/drivers/scsi/ata_piix.c
@@ -153,6 +153,7 @@ static struct ata_port_operations piix_pata_ops = {
 
         .port_start             = ata_port_start,
         .port_stop              = ata_port_stop,
+        .host_stop              = ata_host_stop,
 };
 
 static struct ata_port_operations piix_sata_ops = {
@@ -180,6 +181,7 @@ static struct ata_port_operations piix_sata_ops = {
 
         .port_start             = ata_port_start,
         .port_stop              = ata_port_stop,
+        .host_stop              = ata_host_stop,
 };
 
 static struct ata_port_info piix_port_info[] = {
diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index ee9b96da841e..2b41cd3a8ec6 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -3321,6 +3321,13 @@ void ata_port_stop (struct ata_port *ap)
         dma_free_coherent(dev, ATA_PRD_TBL_SZ, ap->prd, ap->prd_dma);
 }
 
+void ata_host_stop (struct ata_host_set *host_set)
+{
+        if (host_set->mmio_base)
+                iounmap(host_set->mmio_base);
+}
+
+
 /**
  *      ata_host_remove - Unregister SCSI host structure with upper layers
  *      @ap: Port to unregister
@@ -3877,10 +3884,6 @@ void ata_pci_remove_one (struct pci_dev *pdev)
         }
 
         free_irq(host_set->irq, host_set);
-        if (host_set->ops->host_stop)
-                host_set->ops->host_stop(host_set);
-        if (host_set->mmio_base)
-                iounmap(host_set->mmio_base);
 
         for (i = 0; i < host_set->n_ports; i++) {
                 ap = host_set->ports[i];
@@ -3899,6 +3902,9 @@ void ata_pci_remove_one (struct pci_dev *pdev)
                 scsi_host_put(ap->host);
         }
 
+        if (host_set->ops->host_stop)
+                host_set->ops->host_stop(host_set);
+
         kfree(host_set);
 
         pci_release_regions(pdev);
@@ -3996,6 +4002,7 @@ EXPORT_SYMBOL_GPL(ata_chk_err);
 EXPORT_SYMBOL_GPL(ata_exec_command);
 EXPORT_SYMBOL_GPL(ata_port_start);
 EXPORT_SYMBOL_GPL(ata_port_stop);
+EXPORT_SYMBOL_GPL(ata_host_stop);
 EXPORT_SYMBOL_GPL(ata_interrupt);
 EXPORT_SYMBOL_GPL(ata_qc_prep);
 EXPORT_SYMBOL_GPL(ata_bmdma_setup);
diff --git a/drivers/scsi/sata_nv.c b/drivers/scsi/sata_nv.c
index 69009f853a49..b0403ccd8a25 100644
--- a/drivers/scsi/sata_nv.c
+++ b/drivers/scsi/sata_nv.c
@@ -329,6 +329,8 @@ static void nv_host_stop (struct ata_host_set *host_set)
                 host->host_desc->disable_hotplug(host_set);
 
         kfree(host);
+
+        ata_host_stop(host_set);
 }
 
 static int nv_init_one (struct pci_dev *pdev, const struct pci_device_id *ent)
diff --git a/drivers/scsi/sata_promise.c b/drivers/scsi/sata_promise.c
index c4e9e0298122..b18c90582e67 100644
--- a/drivers/scsi/sata_promise.c
+++ b/drivers/scsi/sata_promise.c
@@ -122,6 +122,7 @@ static struct ata_port_operations pdc_ata_ops = {
         .scr_write              = pdc_sata_scr_write,
         .port_start             = pdc_port_start,
         .port_stop              = pdc_port_stop,
+        .host_stop              = ata_host_stop,
 };
 
 static struct ata_port_info pdc_port_info[] = {
diff --git a/drivers/scsi/sata_qstor.c b/drivers/scsi/sata_qstor.c
index dfd362104717..1383e8a28d72 100644
--- a/drivers/scsi/sata_qstor.c
+++ b/drivers/scsi/sata_qstor.c
@@ -536,6 +536,8 @@ static void qs_host_stop(struct ata_host_set *host_set)
 
         writeb(0, mmio_base + QS_HCT_CTRL); /* disable host interrupts */
         writeb(QS_CNFG3_GSRST, mmio_base + QS_HCF_CNFG3); /* global reset */
+
+        ata_host_stop(host_set);
 }
 
 static void qs_host_init(unsigned int chip_id, struct ata_probe_ent *pe)
diff --git a/drivers/scsi/sata_sil.c b/drivers/scsi/sata_sil.c
index 2b2ff48be396..238580d244e6 100644
--- a/drivers/scsi/sata_sil.c
+++ b/drivers/scsi/sata_sil.c
@@ -161,6 +161,7 @@ static struct ata_port_operations sil_ops = {
         .scr_write              = sil_scr_write,
         .port_start             = ata_port_start,
         .port_stop              = ata_port_stop,
+        .host_stop              = ata_host_stop,
 };
 
 static struct ata_port_info sil_port_info[] = {
diff --git a/drivers/scsi/sata_sis.c b/drivers/scsi/sata_sis.c
index 5105ddd08447..e418b89c6b9d 100644
--- a/drivers/scsi/sata_sis.c
+++ b/drivers/scsi/sata_sis.c
@@ -114,6 +114,7 @@ static struct ata_port_operations sis_ops = {
         .scr_write              = sis_scr_write,
         .port_start             = ata_port_start,
         .port_stop              = ata_port_stop,
+        .host_stop              = ata_host_stop,
 };
 
 static struct ata_port_info sis_port_info = {
diff --git a/drivers/scsi/sata_svw.c b/drivers/scsi/sata_svw.c
index 05075bd3a893..edef1fa969fc 100644
--- a/drivers/scsi/sata_svw.c
+++ b/drivers/scsi/sata_svw.c
@@ -313,6 +313,7 @@ static struct ata_port_operations k2_sata_ops = {
         .scr_write              = k2_sata_scr_write,
         .port_start             = ata_port_start,
         .port_stop              = ata_port_stop,
+        .host_stop              = ata_host_stop,
 };
 
 static void k2_sata_setup_port(struct ata_ioports *port, unsigned long base)
diff --git a/drivers/scsi/sata_sx4.c b/drivers/scsi/sata_sx4.c
index 70118650c461..140cea05de3f 100644
--- a/drivers/scsi/sata_sx4.c
+++ b/drivers/scsi/sata_sx4.c
@@ -245,6 +245,8 @@ static void pdc20621_host_stop(struct ata_host_set *host_set)
 
         iounmap(dimm_mmio);
         kfree(hpriv);
+
+        ata_host_stop(host_set);
 }
 
 static int pdc_port_start(struct ata_port *ap)
diff --git a/drivers/scsi/sata_uli.c b/drivers/scsi/sata_uli.c
index 0bff4f475f26..a71fb54eebd3 100644
--- a/drivers/scsi/sata_uli.c
+++ b/drivers/scsi/sata_uli.c
@@ -113,6 +113,7 @@ static struct ata_port_operations uli_ops = {
 
         .port_start             = ata_port_start,
         .port_stop              = ata_port_stop,
+        .host_stop              = ata_host_stop,
 };
 
 static struct ata_port_info uli_port_info = {
diff --git a/drivers/scsi/sata_via.c b/drivers/scsi/sata_via.c
index 3a7830667277..f43183c19a12 100644
--- a/drivers/scsi/sata_via.c
+++ b/drivers/scsi/sata_via.c
@@ -134,6 +134,7 @@ static struct ata_port_operations svia_sata_ops = {
 
         .port_start             = ata_port_start,
         .port_stop              = ata_port_stop,
+        .host_stop              = ata_host_stop,
 };
 
 static struct ata_port_info svia_port_info = {
diff --git a/drivers/scsi/sata_vsc.c b/drivers/scsi/sata_vsc.c
index 2c28f0ad73c2..f67c34330ae9 100644
--- a/drivers/scsi/sata_vsc.c
+++ b/drivers/scsi/sata_vsc.c
@@ -230,6 +230,7 @@ static struct ata_port_operations vsc_sata_ops = {
         .scr_write              = vsc_sata_scr_write,
         .port_start             = ata_port_start,
         .port_stop              = ata_port_stop,
+        .host_stop              = ata_host_stop,
 };
 
 static void __devinit vsc_sata_setup_port(struct ata_ioports *port, unsigned long base)
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 1f7e2039a04e..e74f301e9bae 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -410,6 +410,7 @@ extern u8 ata_chk_err(struct ata_port *ap);
 extern void ata_exec_command(struct ata_port *ap, struct ata_taskfile *tf);
 extern int ata_port_start (struct ata_port *ap);
 extern void ata_port_stop (struct ata_port *ap);
+extern void ata_host_stop (struct ata_host_set *host_set);
 extern irqreturn_t ata_interrupt (int irq, void *dev_instance, struct pt_regs *regs);
 extern void ata_qc_prep(struct ata_queued_cmd *qc);
 extern int ata_qc_issue_prot(struct ata_queued_cmd *qc);