Revert "percpu: fix chunk range calculation"

This reverts commit 264266e6897dd81c894d1c5cbd90b133707b32f3.

The backport had dependencies on other mm/percpu.c restructurings,
like those in commit 020ec6537aa65c18e9084c568d7b94727f2026fd
("percpu: factor out pcpu_addr_in_first/reserved_chunk() and update
per_cpu_ptr_to_phys()").  Rather than drag in more changes, we simply
revert the incomplete backport.

Reported-by: George G. Davis <george_davis@mentor.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/mm/percpu.c b/mm/percpu.c
index 83523d9a351b0bb404eba4ffdce705bb77a3521d..558543b33b52e30d2da622cbc01941004e7911fc 100644 (file)
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -111,9 +111,9 @@ static int pcpu_atom_size __read_mostly;
 static int pcpu_nr_slots __read_mostly;
 static size_t pcpu_chunk_struct_size __read_mostly;
 
-/* cpus with the lowest and highest unit addresses */
-static unsigned int pcpu_low_unit_cpu __read_mostly;
-static unsigned int pcpu_high_unit_cpu __read_mostly;
+/* cpus with the lowest and highest unit numbers */
+static unsigned int pcpu_first_unit_cpu __read_mostly;
+static unsigned int pcpu_last_unit_cpu __read_mostly;
 
 /* the address of the first chunk which starts with the kernel static area */
 void *pcpu_base_addr __read_mostly;
@@ -747,8 +747,8 @@ static void pcpu_pre_unmap_flush(struct pcpu_chunk *chunk,
                                 int page_start, int page_end)
 {
        flush_cache_vunmap(
-               pcpu_chunk_addr(chunk, pcpu_low_unit_cpu, page_start),
-               pcpu_chunk_addr(chunk, pcpu_high_unit_cpu, page_end));
+               pcpu_chunk_addr(chunk, pcpu_first_unit_cpu, page_start),
+               pcpu_chunk_addr(chunk, pcpu_last_unit_cpu, page_end));
 }
 
 static void __pcpu_unmap_pages(unsigned long addr, int nr_pages)
@@ -810,8 +810,8 @@ static void pcpu_post_unmap_tlb_flush(struct pcpu_chunk *chunk,
                                      int page_start, int page_end)
 {
        flush_tlb_kernel_range(
-               pcpu_chunk_addr(chunk, pcpu_low_unit_cpu, page_start),
-               pcpu_chunk_addr(chunk, pcpu_high_unit_cpu, page_end));
+               pcpu_chunk_addr(chunk, pcpu_first_unit_cpu, page_start),
+               pcpu_chunk_addr(chunk, pcpu_last_unit_cpu, page_end));
 }
 
 static int __pcpu_map_pages(unsigned long addr, struct page **pages,
@@ -888,8 +888,8 @@ static void pcpu_post_map_flush(struct pcpu_chunk *chunk,
                                int page_start, int page_end)
 {
        flush_cache_vmap(
-               pcpu_chunk_addr(chunk, pcpu_low_unit_cpu, page_start),
-               pcpu_chunk_addr(chunk, pcpu_high_unit_cpu, page_end));
+               pcpu_chunk_addr(chunk, pcpu_first_unit_cpu, page_start),
+               pcpu_chunk_addr(chunk, pcpu_last_unit_cpu, page_end));
 }
 
 /**
@@ -1345,19 +1345,19 @@ phys_addr_t per_cpu_ptr_to_phys(void *addr)
 {
        void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr);
        bool in_first_chunk = false;
-       unsigned long first_low, first_high;
+       unsigned long first_start, first_end;
        unsigned int cpu;
 
        /*
-        * The following test on unit_low/high isn't strictly
+        * The following test on first_start/end isn't strictly
         * necessary but will speed up lookups of addresses which
         * aren't in the first chunk.
         */
-       first_low = pcpu_chunk_addr(pcpu_first_chunk, pcpu_low_unit_cpu, 0);
-       first_high = pcpu_chunk_addr(pcpu_first_chunk, pcpu_high_unit_cpu,
-                                    pcpu_unit_pages);
-       if ((unsigned long)addr >= first_low &&
-           (unsigned long)addr < first_high) {
+       first_start = pcpu_chunk_addr(pcpu_first_chunk, pcpu_first_unit_cpu, 0);
+       first_end = pcpu_chunk_addr(pcpu_first_chunk, pcpu_last_unit_cpu,
+                                   pcpu_unit_pages);
+       if ((unsigned long)addr >= first_start &&
+           (unsigned long)addr < first_end) {
                for_each_possible_cpu(cpu) {
                        void *start = per_cpu_ptr(base, cpu);
 
@@ -1754,9 +1754,7 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
 
        for (cpu = 0; cpu < nr_cpu_ids; cpu++)
                unit_map[cpu] = UINT_MAX;
-
-       pcpu_low_unit_cpu = NR_CPUS;
-       pcpu_high_unit_cpu = NR_CPUS;
+       pcpu_first_unit_cpu = NR_CPUS;
 
        for (group = 0, unit = 0; group < ai->nr_groups; group++, unit += i) {
                const struct pcpu_group_info *gi = &ai->groups[group];
@@ -1776,13 +1774,9 @@ int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
                        unit_map[cpu] = unit + i;
                        unit_off[cpu] = gi->base_offset + i * ai->unit_size;
 
-                       /* determine low/high unit_cpu */
-                       if (pcpu_low_unit_cpu == NR_CPUS ||
-                           unit_off[cpu] < unit_off[pcpu_low_unit_cpu])
-                               pcpu_low_unit_cpu = cpu;
-                       if (pcpu_high_unit_cpu == NR_CPUS ||
-                           unit_off[cpu] > unit_off[pcpu_high_unit_cpu])
-                               pcpu_high_unit_cpu = cpu;
+                       if (pcpu_first_unit_cpu == NR_CPUS)
+                               pcpu_first_unit_cpu = cpu;
+                       pcpu_last_unit_cpu = cpu;
                }
        }
        pcpu_nr_units = unit;