powerpc/pseries/svm: Drop unused align argument in alloc_shared_lppaca() function

Argument "align" in alloc_shared_lppaca() was unused inside the
function. Let's drop it and update code comment for page alignment.

Signed-off-by: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com>
[mpe: Massage comment wording/formatting]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200612142953.135408-1-sathnaga@linux.vnet.ibm.com

diff --git a/arch/powerpc/kernel/paca.c b/arch/powerpc/kernel/paca.c
index 2168372..5239a42 100644 (file)
--- a/arch/powerpc/kernel/paca.c
+++ b/arch/powerpc/kernel/paca.c
@@ -57,8 +57,8 @@ static void *__init alloc_paca_data(unsigned long size, unsigned long align,
 
 #define LPPACA_SIZE 0x400
 
-static void *__init alloc_shared_lppaca(unsigned long size, unsigned long align,
-                                       unsigned long limit, int cpu)
+static void *__init alloc_shared_lppaca(unsigned long size, unsigned long limit,
+                                       int cpu)
 {
        size_t shared_lppaca_total_size = PAGE_ALIGN(nr_cpu_ids * LPPACA_SIZE);
        static unsigned long shared_lppaca_size;
@@ -68,6 +68,13 @@ static void *__init alloc_shared_lppaca(unsigned long size, unsigned long align,
        if (!shared_lppaca) {
                memblock_set_bottom_up(true);
 
+               /*
+                * See Documentation/powerpc/ultravisor.rst for more details.
+                *
+                * UV/HV data sharing is in PAGE_SIZE granularity. In order to
+                * minimize the number of pages shared, align the allocation to
+                * PAGE_SIZE.
+                */
                shared_lppaca =
                        memblock_alloc_try_nid(shared_lppaca_total_size,
                                               PAGE_SIZE, MEMBLOCK_LOW_LIMIT,
@@ -122,7 +129,7 @@ static struct lppaca * __init new_lppaca(int cpu, unsigned long limit)
                return NULL;
 
        if (is_secure_guest())
-               lp = alloc_shared_lppaca(LPPACA_SIZE, 0x400, limit, cpu);
+               lp = alloc_shared_lppaca(LPPACA_SIZE, limit, cpu);
        else
                lp = alloc_paca_data(LPPACA_SIZE, 0x400, limit, cpu);