[xen master] Argo: drop meaningless mfn_valid() check

[patchbot@xxxxxxx]

commit 9bb281d328cb7c6319f44897a2c29909eeb8674b
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Wed Feb 14 10:38:38 2024 +0100
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Wed Feb 14 10:38:38 2024 +0100

    Argo: drop meaningless mfn_valid() check
    
    Holding a valid struct page_info * in hands already means the referenced
    MFN is valid; there's no need to check that again. Convert the checking
    logic to a switch(), to help keeping the extra (and questionable) x86-
    only check in somewhat tidy shape.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Christopher Clark <christopher.w.clark@xxxxxxxxx>
---
 xen/common/argo.c | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/xen/common/argo.c b/xen/common/argo.c
index f29fa720fc..5dc5e45c7b 100644
--- a/xen/common/argo.c
+++ b/xen/common/argo.c
@@ -1421,15 +1421,24 @@ find_ring_mfn(struct domain *d, gfn_t gfn, mfn_t *mfn)
         return ret;
 
     *mfn = page_to_mfn(page);
-    if ( !mfn_valid(*mfn) )
-        ret = -EINVAL;
+
+    switch ( p2mt )
+    {
+    case p2m_ram_rw:
+        if ( !get_page_and_type(page, d, PGT_writable_page) )
+            ret = -EINVAL;
+        break;
+
 #ifdef CONFIG_X86
-    else if ( p2mt == p2m_ram_logdirty )
+    case p2m_ram_logdirty:
         ret = -EAGAIN;
+        break;
 #endif
-    else if ( (p2mt != p2m_ram_rw) ||
-              !get_page_and_type(page, d, PGT_writable_page) )
+
+    default:
         ret = -EINVAL;
+        break;
+    }
 
     put_page(page);
 
--
generated by git-patchbot for /home/xen/git/xen.git#master