[Qemu-devel] [RFC v2 1/2] hw/pvrdma: make DSR mapping idempotent in load_dsr()

[Sukrit Bhatnagar <skrtbhtngr@gmail.com>]

Map to DSR only when there is no mapping done already i.e., when
dev->dsr_info.dsr is NULL. This allows the rest of mappings and
ring inits to be done by calling load_dsr() when DSR has already
been mapped to, somewhere else.

Move free_dsr() out of load_dsr() and call it before the latter
as and when needed. This aids the case where load_dsr() is called
having DSR mapping already done, but the rest of map and init
operations are pending, and prevents an unmap of the DSR.

Cc: Marcel Apfelbaum <marcel.apfelbaum@gmail.com>
Cc: Yuval Shaia <yuval.shaia@oracle.com>
Signed-off-by: Sukrit Bhatnagar <skrtbhtngr@gmail.com>
---
 hw/rdma/vmw/pvrdma_main.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/hw/rdma/vmw/pvrdma_main.c b/hw/rdma/vmw/pvrdma_main.c
index adcf79cd63..6c90db96f9 100644
--- a/hw/rdma/vmw/pvrdma_main.c
+++ b/hw/rdma/vmw/pvrdma_main.c
@@ -172,15 +172,15 @@ static int load_dsr(PVRDMADev *dev)
     DSRInfo *dsr_info;
     struct pvrdma_device_shared_region *dsr;
 
-    free_dsr(dev);
-
-    /* Map to DSR */
-    dev->dsr_info.dsr = rdma_pci_dma_map(pci_dev, dev->dsr_info.dma,
-                              sizeof(struct pvrdma_device_shared_region));
     if (!dev->dsr_info.dsr) {
-        rdma_error_report("Failed to map to DSR");
-        rc = -ENOMEM;
-        goto out;
+        /* Map to DSR */
+        dev->dsr_info.dsr = rdma_pci_dma_map(pci_dev, dev->dsr_info.dma,
+                                  sizeof(struct pvrdma_device_shared_region));
+        if (!dev->dsr_info.dsr) {
+            rdma_error_report("Failed to map to DSR");
+            rc = -ENOMEM;
+            goto out;
+        }
     }
 
     /* Shortcuts */
@@ -402,6 +402,7 @@ static void pvrdma_regs_write(void *opaque, hwaddr addr, uint64_t val,
     case PVRDMA_REG_DSRHIGH:
         trace_pvrdma_regs_write(addr, val, "DSRHIGH", "");
         dev->dsr_info.dma |= val << 32;
+        free_dsr(dev);
         load_dsr(dev);
         init_dsr_dev_caps(dev);
         break;
-- 
2.21.0