[PATCH v1 1/5] vpci: const-ify some pdev instances

[Stewart Hildebrand <stewart.hildebrand@xxxxxxx>]

Since 622bdd962822 ("vpci/header: handle p2m range sets per BAR"), a
non-const pdev is no longer needed for error handling in
vpci_process_pending(). Const-ify pdev in vpci_process_pending(),
defer_map(), and struct vpci_vcpu.

Get rid of const-removal workaround in modify_bars().

Take the opportunity to remove an unused parameter in defer_map().

Signed-off-by: Stewart Hildebrand <stewart.hildebrand@xxxxxxx>
---
This is prerequisite for ("vpci: use separate rangeset for BAR
unmapping") in order to call defer_map() with a const pdev.
---
 xen/drivers/vpci/header.c | 16 ++++------------
 xen/include/xen/vpci.h    |  2 +-
 2 files changed, 5 insertions(+), 13 deletions(-)

diff --git a/xen/drivers/vpci/header.c b/xen/drivers/vpci/header.c
index 1f48f2aac64e..e42c8efa2302 100644
--- a/xen/drivers/vpci/header.c
+++ b/xen/drivers/vpci/header.c
@@ -175,7 +175,7 @@ static void modify_decoding(const struct pci_dev *pdev, 
uint16_t cmd,
 
 bool vpci_process_pending(struct vcpu *v)
 {
-    struct pci_dev *pdev = v->vpci.pdev;
+    const struct pci_dev *pdev = v->vpci.pdev;
     struct vpci_header *header = NULL;
     unsigned int i;
 
@@ -283,8 +283,7 @@ static int __init apply_map(struct domain *d, const struct 
pci_dev *pdev,
     return rc;
 }
 
-static void defer_map(struct domain *d, struct pci_dev *pdev,
-                      uint16_t cmd, bool rom_only)
+static void defer_map(const struct pci_dev *pdev, uint16_t cmd, bool rom_only)
 {
     struct vcpu *curr = current;
 
@@ -308,7 +307,7 @@ static void defer_map(struct domain *d, struct pci_dev 
*pdev,
 static int modify_bars(const struct pci_dev *pdev, uint16_t cmd, bool rom_only)
 {
     struct vpci_header *header = &pdev->vpci->header;
-    struct pci_dev *tmp, *dev = NULL;
+    struct pci_dev *tmp;
     const struct domain *d;
     const struct vpci_msix *msix = pdev->vpci->msix;
     unsigned int i, j;
@@ -450,11 +449,6 @@ static int modify_bars(const struct pci_dev *pdev, 
uint16_t cmd, bool rom_only)
 
             if ( tmp == pdev )
             {
-                /*
-                 * Need to store the device so it's not constified and 
defer_map
-                 * can modify it in case of error.
-                 */
-                dev = tmp;
                 if ( !rom_only )
                     /*
                      * If memory decoding is toggled avoid checking against the
@@ -507,8 +501,6 @@ static int modify_bars(const struct pci_dev *pdev, uint16_t 
cmd, bool rom_only)
         d = dom_xen;
     }
 
-    ASSERT(dev);
-
     if ( system_state < SYS_STATE_active )
     {
         /*
@@ -523,7 +515,7 @@ static int modify_bars(const struct pci_dev *pdev, uint16_t 
cmd, bool rom_only)
         return apply_map(pdev->domain, pdev, cmd);
     }
 
-    defer_map(dev->domain, dev, cmd, rom_only);
+    defer_map(pdev, cmd, rom_only);
 
     return 0;
 }
diff --git a/xen/include/xen/vpci.h b/xen/include/xen/vpci.h
index 475981cb8155..27eebdcef170 100644
--- a/xen/include/xen/vpci.h
+++ b/xen/include/xen/vpci.h
@@ -194,7 +194,7 @@ struct vpci {
 
 struct vpci_vcpu {
     /* Per-vcpu structure to store state while {un}mapping of PCI BARs. */
-    struct pci_dev *pdev;
+    const struct pci_dev *pdev;
     uint16_t cmd;
     bool rom_only : 1;
 };
-- 
2.49.0