linux-kernel - [PATCH] dax: use switch statement over chained ifs

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Message-ID: <CAPOgqxF_xEgKspetRJ=wq1_qSG3h8mkyXC58TXkUvx0agzEm_A@mail.gmail.com>
Date:   Mon, 16 Jan 2023 18:11:00 -0800
From:   Amy Parker <apark0006@...dent.cerritos.edu>
To:     willy@...radead.org
Cc:     linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] dax: use switch statement over chained ifs

This patch uses a switch statement for pe_order, which improves
readability and on some platforms may minorly improve performance. It
also, to improve readability, recognizes that `PAGE_SHIFT - PAGE_SHIFT' is
a constant, and uses 0 in its place instead.

Signed-off-by: Amy Parker <apark0006@...dent.cerritos.edu>
---
 fs/dax.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/fs/dax.c b/fs/dax.c
index c48a3a93ab29..e8beed601384 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -32,13 +32,16 @@

 static inline unsigned int pe_order(enum page_entry_size pe_size)
 {
-    if (pe_size == PE_SIZE_PTE)
-        return PAGE_SHIFT - PAGE_SHIFT;
-    if (pe_size == PE_SIZE_PMD)
+    switch (pe_size) {
+    case PE_SIZE_PTE:
+        return 0;
+    case PE_SIZE_PMD:
         return PMD_SHIFT - PAGE_SHIFT;
-    if (pe_size == PE_SIZE_PUD)
+    case PE_SIZE_PUD:
         return PUD_SHIFT - PAGE_SHIFT;
-    return ~0;
+    default:
+        return ~0;
+    }
 }

 /* We choose 4096 entries - same as per-zone page wait tables */
-- 
2.39.0