staging: gasket: page_table: simplify gasket_components_to_dev_address

Refactor gasket_components_to_dev_address to be faster and easier to
understand. The old implementation was unnecessarily complex and masked
the page_index for simple addresses but not extended ones. It makes the
most sense for this function to perform no such masking.

Signed-off-by: Nick Ewalt <nicholasewalt@google.com>
Signed-off-by: Todd Poynor <toddpoynor@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/gasket/gasket_page_table.c b/drivers/staging/gasket/gasket_page_table.c
index ec93595..c2fbab7 100644 (file)
--- a/drivers/staging/gasket/gasket_page_table.c
+++ b/drivers/staging/gasket/gasket_page_table.c
@@ -699,26 +699,9 @@ static ulong gasket_components_to_dev_address(struct gasket_page_table *pg_tbl,
                                              int is_simple, uint page_index,
                                              uint offset)
 {
-       ulong lvl0_index, lvl1_index;
+       ulong dev_addr = (page_index << GASKET_SIMPLE_PAGE_SHIFT) | offset;
 
-       if (is_simple) {
-               /* Return simple addresses directly. */
-               lvl0_index = page_index & (pg_tbl->config.total_entries - 1);
-               return (lvl0_index << GASKET_SIMPLE_PAGE_SHIFT) | offset;
-       }
-
-       /*
-        * This could be compressed into fewer statements, but
-        * A) the compiler should optimize it
-        * B) this is not slow
-        * C) this is an uncommon operation
-        * D) this is actually readable this way.
-        */
-       lvl0_index = page_index / GASKET_PAGES_PER_SUBTABLE;
-       lvl1_index = page_index & (GASKET_PAGES_PER_SUBTABLE - 1);
-       return (pg_tbl)->extended_flag |
-              (lvl0_index << GASKET_EXTENDED_LVL0_SHIFT) |
-              (lvl1_index << GASKET_EXTENDED_LVL1_SHIFT) | offset;
+       return is_simple ? dev_addr : (pg_tbl->extended_flag | dev_addr);
 }
 
 /*