[PATCH v3 4/7] xen: move max_pfn in xen_memory_setup() out of function scope

[Juergen Gross <jgross@xxxxxxxx>]

Instead of having max_pfn as a local variable of xen_memory_setup(),
make it a static variable in setup.c instead. This avoids having to
pass it to subfunctions, which will be needed in more cases in future.

Rename it to ini_nr_pages, as the value denotes the currently usable
number of memory pages as passed from the hypervisor at boot time.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Tested-by: Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>
Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 arch/x86/xen/setup.c | 52 ++++++++++++++++++++++----------------------
 1 file changed, 26 insertions(+), 26 deletions(-)

diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index dba68951ed6b..2c79bb5a9cd0 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -46,6 +46,9 @@ bool xen_pv_pci_possible;
 /* E820 map used during setting up memory. */
 static struct e820_table xen_e820_table __initdata;
 
+/* Number of initially usable memory pages. */
+static unsigned long ini_nr_pages __initdata;
+
 /*
  * Buffer used to remap identity mapped pages. We only need the virtual space.
  * The physical page behind this address is remapped as needed to different
@@ -212,7 +215,7 @@ static int __init xen_free_mfn(unsigned long mfn)
  * as a fallback if the remapping fails.
  */
 static void __init xen_set_identity_and_release_chunk(unsigned long start_pfn,
-                       unsigned long end_pfn, unsigned long nr_pages)
+                                                     unsigned long end_pfn)
 {
        unsigned long pfn, end;
        int ret;
@@ -220,7 +223,7 @@ static void __init 
xen_set_identity_and_release_chunk(unsigned long start_pfn,
        WARN_ON(start_pfn > end_pfn);
 
        /* Release pages first. */
-       end = min(end_pfn, nr_pages);
+       end = min(end_pfn, ini_nr_pages);
        for (pfn = start_pfn; pfn < end; pfn++) {
                unsigned long mfn = pfn_to_mfn(pfn);
 
@@ -341,15 +344,14 @@ static void __init xen_do_set_identity_and_remap_chunk(
  * to Xen and not remapped.
  */
 static unsigned long __init xen_set_identity_and_remap_chunk(
-       unsigned long start_pfn, unsigned long end_pfn, unsigned long nr_pages,
-       unsigned long remap_pfn)
+       unsigned long start_pfn, unsigned long end_pfn, unsigned long remap_pfn)
 {
        unsigned long pfn;
        unsigned long i = 0;
        unsigned long n = end_pfn - start_pfn;
 
        if (remap_pfn == 0)
-               remap_pfn = nr_pages;
+               remap_pfn = ini_nr_pages;
 
        while (i < n) {
                unsigned long cur_pfn = start_pfn + i;
@@ -358,19 +360,19 @@ static unsigned long __init 
xen_set_identity_and_remap_chunk(
                unsigned long remap_range_size;
 
                /* Do not remap pages beyond the current allocation */
-               if (cur_pfn >= nr_pages) {
+               if (cur_pfn >= ini_nr_pages) {
                        /* Identity map remaining pages */
                        set_phys_range_identity(cur_pfn, cur_pfn + size);
                        break;
                }
-               if (cur_pfn + size > nr_pages)
-                       size = nr_pages - cur_pfn;
+               if (cur_pfn + size > ini_nr_pages)
+                       size = ini_nr_pages - cur_pfn;
 
                remap_range_size = xen_find_pfn_range(&remap_pfn);
                if (!remap_range_size) {
                        pr_warn("Unable to find available pfn range, not 
remapping identity pages\n");
                        xen_set_identity_and_release_chunk(cur_pfn,
-                                               cur_pfn + left, nr_pages);
+                                                          cur_pfn + left);
                        break;
                }
                /* Adjust size to fit in current e820 RAM region */
@@ -397,18 +399,18 @@ static unsigned long __init 
xen_set_identity_and_remap_chunk(
 }
 
 static unsigned long __init xen_count_remap_pages(
-       unsigned long start_pfn, unsigned long end_pfn, unsigned long nr_pages,
+       unsigned long start_pfn, unsigned long end_pfn,
        unsigned long remap_pages)
 {
-       if (start_pfn >= nr_pages)
+       if (start_pfn >= ini_nr_pages)
                return remap_pages;
 
-       return remap_pages + min(end_pfn, nr_pages) - start_pfn;
+       return remap_pages + min(end_pfn, ini_nr_pages) - start_pfn;
 }
 
-static unsigned long __init xen_foreach_remap_area(unsigned long nr_pages,
+static unsigned long __init xen_foreach_remap_area(
        unsigned long (*func)(unsigned long start_pfn, unsigned long end_pfn,
-                             unsigned long nr_pages, unsigned long last_val))
+                             unsigned long last_val))
 {
        phys_addr_t start = 0;
        unsigned long ret_val = 0;
@@ -436,8 +438,7 @@ static unsigned long __init xen_foreach_remap_area(unsigned 
long nr_pages,
                                end_pfn = PFN_UP(entry->addr);
 
                        if (start_pfn < end_pfn)
-                               ret_val = func(start_pfn, end_pfn, nr_pages,
-                                              ret_val);
+                               ret_val = func(start_pfn, end_pfn, ret_val);
                        start = end;
                }
        }
@@ -700,7 +701,7 @@ static void __init xen_reserve_xen_mfnlist(void)
  **/
 char * __init xen_memory_setup(void)
 {
-       unsigned long max_pfn, pfn_s, n_pfns;
+       unsigned long pfn_s, n_pfns;
        phys_addr_t mem_end, addr, size, chunk_size;
        u32 type;
        int rc;
@@ -712,9 +713,8 @@ char * __init xen_memory_setup(void)
        int op;
 
        xen_parse_512gb();
-       max_pfn = xen_get_pages_limit();
-       max_pfn = min(max_pfn, xen_start_info->nr_pages);
-       mem_end = PFN_PHYS(max_pfn);
+       ini_nr_pages = min(xen_get_pages_limit(), xen_start_info->nr_pages);
+       mem_end = PFN_PHYS(ini_nr_pages);
 
        memmap.nr_entries = ARRAY_SIZE(xen_e820_table.entries);
        set_xen_guest_handle(memmap.buffer, xen_e820_table.entries);
@@ -789,10 +789,10 @@ char * __init xen_memory_setup(void)
        max_pages = xen_get_max_pages();
 
        /* How many extra pages do we need due to remapping? */
-       max_pages += xen_foreach_remap_area(max_pfn, xen_count_remap_pages);
+       max_pages += xen_foreach_remap_area(xen_count_remap_pages);
 
-       if (max_pages > max_pfn)
-               extra_pages += max_pages - max_pfn;
+       if (max_pages > ini_nr_pages)
+               extra_pages += max_pages - ini_nr_pages;
 
        /*
         * Clamp the amount of extra memory to a EXTRA_MEM_RATIO
@@ -801,8 +801,8 @@ char * __init xen_memory_setup(void)
         * Make sure we have no memory above max_pages, as this area
         * isn't handled by the p2m management.
         */
-       maxmem_pages = EXTRA_MEM_RATIO * min(max_pfn, PFN_DOWN(MAXMEM));
-       extra_pages = min3(maxmem_pages, extra_pages, max_pages - max_pfn);
+       maxmem_pages = EXTRA_MEM_RATIO * min(ini_nr_pages, PFN_DOWN(MAXMEM));
+       extra_pages = min3(maxmem_pages, extra_pages, max_pages - ini_nr_pages);
        i = 0;
        addr = xen_e820_table.entries[0].addr;
        size = xen_e820_table.entries[0].size;
@@ -885,7 +885,7 @@ char * __init xen_memory_setup(void)
         * Set identity map on non-RAM pages and prepare remapping the
         * underlying RAM.
         */
-       xen_foreach_remap_area(max_pfn, xen_set_identity_and_remap_chunk);
+       xen_foreach_remap_area(xen_set_identity_and_remap_chunk);
 
        pr_info("Released %ld page(s)\n", xen_released_pages);
 
-- 
2.43.0