ehea: Fix memory hotplug support

This patch implements the memory notifier to update the busmap
instantly instead of rebuilding the whole map. This is necessary
because walk_memory_resource provides different information than
required during memory hotplug.

Signed-off-by: Hannes Hering <hering2@de.ibm.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 101 insertions, 30 deletions

diff --git a/drivers/net/ehea/ehea_qmr.c b/drivers/net/ehea/ehea_qmr.c
index db8a9257e680..9b61dc9865d1 100644
--- a/drivers/net/ehea/ehea_qmr.c
+++ b/drivers/net/ehea/ehea_qmr.c
@@ -567,7 +567,7 @@ static inline int ehea_calc_index(unsigned long i, unsigned long s)
 static inline int ehea_init_top_bmap(struct ehea_top_bmap *ehea_top_bmap,
                                      int dir)
 {
-        if(!ehea_top_bmap->dir[dir]) {
+        if (!ehea_top_bmap->dir[dir]) {
                 ehea_top_bmap->dir[dir] =
                         kzalloc(sizeof(struct ehea_dir_bmap), GFP_KERNEL);
                 if (!ehea_top_bmap->dir[dir])
@@ -578,7 +578,7 @@ static inline int ehea_init_top_bmap(struct ehea_top_bmap *ehea_top_bmap,
 
 static inline int ehea_init_bmap(struct ehea_bmap *ehea_bmap, int top, int dir)
 {
-        if(!ehea_bmap->top[top]) {
+        if (!ehea_bmap->top[top]) {
                 ehea_bmap->top[top] =
                         kzalloc(sizeof(struct ehea_top_bmap), GFP_KERNEL);
                 if (!ehea_bmap->top[top])
@@ -587,53 +587,124 @@ static inline int ehea_init_bmap(struct ehea_bmap *ehea_bmap, int top, int dir)
         return ehea_init_top_bmap(ehea_bmap->top[top], dir);
 }
 
-static int ehea_create_busmap_callback(unsigned long pfn,
-                                       unsigned long nr_pages, void *arg)
-{
-        unsigned long i, mr_len, start_section, end_section;
-        start_section = (pfn * PAGE_SIZE) / EHEA_SECTSIZE;
-        end_section = start_section + ((nr_pages * PAGE_SIZE) / EHEA_SECTSIZE);
-        mr_len = *(unsigned long *)arg;
+static DEFINE_MUTEX(ehea_busmap_mutex);
+static unsigned long ehea_mr_len;
 
-        if (!ehea_bmap)
-                ehea_bmap = kzalloc(sizeof(struct ehea_bmap), GFP_KERNEL);
-        if (!ehea_bmap)
-                return -ENOMEM;
+#define EHEA_BUSMAP_ADD_SECT 1
+#define EHEA_BUSMAP_REM_SECT 0
 
-        for (i = start_section; i < end_section; i++) {
-                int ret;
-                int top, dir, idx;
-                u64 vaddr;
+static void ehea_rebuild_busmap(void)
+{
+        u64 vaddr = EHEA_BUSMAP_START;
+        int top, dir, idx;
+
+        for (top = 0; top < EHEA_MAP_ENTRIES; top++) {
+                struct ehea_top_bmap *ehea_top;
+                int valid_dir_entries = 0;
 
-                top = ehea_calc_index(i, EHEA_TOP_INDEX_SHIFT);
-                dir = ehea_calc_index(i, EHEA_DIR_INDEX_SHIFT);
+                if (!ehea_bmap->top[top])
+                        continue;
+                ehea_top = ehea_bmap->top[top];
+                for (dir = 0; dir < EHEA_MAP_ENTRIES; dir++) {
+                        struct ehea_dir_bmap *ehea_dir;
+                        int valid_entries = 0;
 
-                ret = ehea_init_bmap(ehea_bmap, top, dir);
-                if(ret)
-                        return ret;
+                        if (!ehea_top->dir[dir])
+                                continue;
+                        valid_dir_entries++;
+                        ehea_dir = ehea_top->dir[dir];
+                        for (idx = 0; idx < EHEA_MAP_ENTRIES; idx++) {
+                                if (!ehea_dir->ent[idx])
+                                        continue;
+                                valid_entries++;
+                                ehea_dir->ent[idx] = vaddr;
+                                vaddr += EHEA_SECTSIZE;
+                        }
+                        if (!valid_entries) {
+                                ehea_top->dir[dir] = NULL;
+                                kfree(ehea_dir);
+                        }
+                }
+                if (!valid_dir_entries) {
+                        ehea_bmap->top[top] = NULL;
+                        kfree(ehea_top);
+                }
+        }
+}
 
-                idx = i & EHEA_INDEX_MASK;
-                vaddr = EHEA_BUSMAP_START + mr_len + i * EHEA_SECTSIZE;
+static int ehea_update_busmap(unsigned long pfn, unsigned long pgnum, int add)
+{
+        unsigned long i, start_section, end_section;
 
-                ehea_bmap->top[top]->dir[dir]->ent[idx] = vaddr;
+        if (!ehea_bmap) {
+                ehea_bmap = kzalloc(sizeof(struct ehea_bmap), GFP_KERNEL);
+                if (!ehea_bmap)
+                        return -ENOMEM;
         }
 
-        mr_len += nr_pages * PAGE_SIZE;
-        *(unsigned long *)arg = mr_len;
+        start_section = (pfn * PAGE_SIZE) / EHEA_SECTSIZE;
+        end_section = start_section + ((pgnum * PAGE_SIZE) / EHEA_SECTSIZE);
+        /* Mark entries as valid or invalid only; address is assigned later */
+        for (i = start_section; i < end_section; i++) {
+                u64 flag;
+                int top = ehea_calc_index(i, EHEA_TOP_INDEX_SHIFT);
+                int dir = ehea_calc_index(i, EHEA_DIR_INDEX_SHIFT);
+                int idx = i & EHEA_INDEX_MASK;
+                
+                if (add) {
+                        int ret = ehea_init_bmap(ehea_bmap, top, dir);
+                        if (ret)
+                                return ret;
+                        flag = 1; /* valid */
+                        ehea_mr_len += EHEA_SECTSIZE;
+                } else {
+                        if (!ehea_bmap->top[top])
+                                continue;
+                        if (!ehea_bmap->top[top]->dir[dir])
+                                continue;
+                        flag = 0; /* invalid */
+                        ehea_mr_len -= EHEA_SECTSIZE;
+                }
 
+                ehea_bmap->top[top]->dir[dir]->ent[idx] = flag;
+        }
+        ehea_rebuild_busmap(); /* Assign contiguous addresses for mr */
         return 0;
 }
 
-static unsigned long ehea_mr_len;
+int ehea_add_sect_bmap(unsigned long pfn, unsigned long nr_pages)
+{
+        int ret;
 
-static DEFINE_MUTEX(ehea_busmap_mutex);
+        mutex_lock(&ehea_busmap_mutex);
+        ret = ehea_update_busmap(pfn, nr_pages, EHEA_BUSMAP_ADD_SECT);
+        mutex_unlock(&ehea_busmap_mutex);
+        return ret;
+}
+
+int ehea_rem_sect_bmap(unsigned long pfn, unsigned long nr_pages)
+{
+        int ret;
+
+        mutex_lock(&ehea_busmap_mutex);
+        ret = ehea_update_busmap(pfn, nr_pages, EHEA_BUSMAP_REM_SECT);
+        mutex_unlock(&ehea_busmap_mutex);
+        return ret;
+}
+
+static int ehea_create_busmap_callback(unsigned long pfn,
+                                       unsigned long nr_pages, void *arg)
+{
+        return ehea_update_busmap(pfn, nr_pages, EHEA_BUSMAP_ADD_SECT);
+}
 
 int ehea_create_busmap(void)
 {
         int ret;
+
         mutex_lock(&ehea_busmap_mutex);
         ehea_mr_len = 0;
-        ret = walk_memory_resource(0, 1ULL << MAX_PHYSMEM_BITS, &ehea_mr_len,
+        ret = walk_memory_resource(0, 1ULL << MAX_PHYSMEM_BITS, NULL,
                                    ehea_create_busmap_callback);
         mutex_unlock(&ehea_busmap_mutex);
         return ret;