[PATCH] xen/x86: Use macro DIV_ROUND_UP

[PATCH] xen/x86: Use macro DIV_ROUND_UP

[Simran Singhal]

Use the DIV_ROUND_UP macro to replace open-coded divisor calculation
(((n) + (d) - 1) /(d)) to improve readability.

Signed-off-by: Simran Singhal <singhalsimran0@gmail.com>
---
 xen/arch/x86/mm.c        | 2 +-
 xen/arch/x86/tboot.c     | 2 +-
 xen/arch/x86/x86_64/mm.c | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/xen/arch/x86/mm.c b/xen/arch/x86/mm.c
index c7617f80e8..a381eac81c 100644
--- a/xen/arch/x86/mm.c
+++ b/xen/arch/x86/mm.c
@@ -240,7 +240,7 @@ static void __init init_frametable_chunk(void *start, void *end)
 void __init init_frametable(void)
 {
     unsigned int sidx, eidx, nidx;
-    unsigned int max_idx = (max_pdx + PDX_GROUP_COUNT - 1) / PDX_GROUP_COUNT;
+    unsigned int max_idx = DIV_ROUND_UP(max_pdx, PDX_GROUP_COUNT);
     struct page_info *end_pg, *top_pg;
 
     BUILD_BUG_ON(XEN_VIRT_END > FRAMETABLE_VIRT_START);
diff --git a/xen/arch/x86/tboot.c b/xen/arch/x86/tboot.c
index 102c3cd203..320e06f129 100644
--- a/xen/arch/x86/tboot.c
+++ b/xen/arch/x86/tboot.c
@@ -310,7 +310,7 @@ static void tboot_gen_frametable_integrity(const uint8_t key[TB_KEY_SIZE],
                                            vmac_t *mac)
 {
     unsigned int sidx, eidx, nidx;
-    unsigned int max_idx = (max_pdx + PDX_GROUP_COUNT - 1)/PDX_GROUP_COUNT;
+    unsigned int max_idx = DIV_ROUND_UP(max_pdx, PDX_GROUP_COUNT);
     uint8_t nonce[16] = {};
     vmac_ctx_t ctx;
 
diff --git a/xen/arch/x86/x86_64/mm.c b/xen/arch/x86/x86_64/mm.c
index b7ce833ffc..cee836ec37 100644
--- a/xen/arch/x86/x86_64/mm.c
+++ b/xen/arch/x86/x86_64/mm.c
@@ -801,7 +801,7 @@ static int extend_frame_table(struct mem_hotadd_info *info)
     spfn = _mfn(info->spfn);
     epfn = _mfn(info->epfn);
 
-    eidx = (mfn_to_pdx(epfn) + PDX_GROUP_COUNT - 1) / PDX_GROUP_COUNT;
+    eidx = DIV_ROUND_UP(mfn_to_pdx(epfn), PDX_GROUP_COUNT);
     nidx = cidx = mfn_to_pdx(spfn)/PDX_GROUP_COUNT;
 
     ASSERT( mfn_to_pdx(epfn) <= (DIRECTMAP_SIZE >> PAGE_SHIFT) &&
-- 
2.17.1

Re: [PATCH] xen/x86: Use macro DIV_ROUND_UP

[Andrew Cooper]

On 02/04/2020 16:53, Simran Singhal wrote:
> Use the DIV_ROUND_UP macro to replace open-coded divisor calculation
> (((n) + (d) - 1) /(d)) to improve readability.
>
> Signed-off-by: Simran Singhal <singhalsimran0@gmail.com>

Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>