drm/nouveau: greatly simplify mm, killing some bugs in the process

Reviewed-by: Francisco Jerez <currojerez@riseup.net>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

3 files changed, 52 insertions, 160 deletions

diff --git a/drivers/gpu/drm/nouveau/nouveau_mem.c b/drivers/gpu/drm/nouveau/nouveau_mem.c
index 69044eb104b..26347b7cd87 100644
--- a/drivers/gpu/drm/nouveau/nouveau_mem.c
+++ b/drivers/gpu/drm/nouveau/nouveau_mem.c
@@ -742,30 +742,24 @@ nouveau_vram_manager_debug(struct ttm_mem_type_manager *man, const char *prefix)
 {
         struct nouveau_mm *mm = man->priv;
         struct nouveau_mm_node *r;
-        u64 total = 0, ttotal[3] = {}, tused[3] = {}, tfree[3] = {};
-        int i;
+        u32 total = 0, free = 0;
 
         mutex_lock(&mm->mutex);
         list_for_each_entry(r, &mm->nodes, nl_entry) {
-                printk(KERN_DEBUG "%s %s-%d: 0x%010llx 0x%010llx\n",
-                       prefix, r->free ? "free" : "used", r->type,
-                       ((u64)r->offset << 12),
+                printk(KERN_DEBUG "%s %d: 0x%010llx 0x%010llx\n",
+                       prefix, r->type, ((u64)r->offset << 12),
                        (((u64)r->offset + r->length) << 12));
+
                 total += r->length;
-                ttotal[r->type] += r->length;
-                if (r->free)
-                        tfree[r->type] += r->length;
-                else
-                        tused[r->type] += r->length;
+                if (!r->type)
+                        free += r->length;
         }
         mutex_unlock(&mm->mutex);
 
-        printk(KERN_DEBUG "%s  total: 0x%010llx\n", prefix, total << 12);
-        for (i = 0; i < 3; i++) {
-                printk(KERN_DEBUG "%s type %d: 0x%010llx, "
-                                  "used 0x%010llx, free 0x%010llx\n", prefix,
-                       i, ttotal[i] << 12, tused[i] << 12, tfree[i] << 12);
-        }
+        printk(KERN_DEBUG "%s  total: 0x%010llx free: 0x%010llx\n",
+               prefix, (u64)total << 12, (u64)free << 12);
+        printk(KERN_DEBUG "%s  block: 0x%08x\n",
+               prefix, mm->block_size << 12);
 }
 
 const struct ttm_mem_type_manager_func nouveau_vram_manager = {
diff --git a/drivers/gpu/drm/nouveau/nouveau_mm.c b/drivers/gpu/drm/nouveau/nouveau_mm.c
index cdbb11eb701..8844b50c3e5 100644
--- a/drivers/gpu/drm/nouveau/nouveau_mm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_mm.c
@@ -48,175 +48,76 @@ region_split(struct nouveau_mm *rmm, struct nouveau_mm_node *a, u32 size)
 
         b->offset = a->offset;
         b->length = size;
-        b->free   = a->free;
         b->type   = a->type;
         a->offset += size;
         a->length -= size;
         list_add_tail(&b->nl_entry, &a->nl_entry);
-        if (b->free)
+        if (b->type == 0)
                 list_add_tail(&b->fl_entry, &a->fl_entry);
         return b;
 }
 
-static struct nouveau_mm_node *
-nouveau_mm_merge(struct nouveau_mm *rmm, struct nouveau_mm_node *this)
-{
-        struct nouveau_mm_node *prev, *next;
-
-        /* try to merge with free adjacent entries of same type */
-        prev = list_entry(this->nl_entry.prev, struct nouveau_mm_node, nl_entry);
-        if (this->nl_entry.prev != &rmm->nodes) {
-                if (prev->free && prev->type == this->type) {
-                        prev->length += this->length;
-                        region_put(rmm, this);
-                        this = prev;
-                }
-        }
-
-        next = list_entry(this->nl_entry.next, struct nouveau_mm_node, nl_entry);
-        if (this->nl_entry.next != &rmm->nodes) {
-                if (next->free && next->type == this->type) {
-                        next->offset  = this->offset;
-                        next->length += this->length;
-                        region_put(rmm, this);
-                        this = next;
-                }
-        }
-
-        return this;
-}
+#define node(root, dir) ((root)->nl_entry.dir == &rmm->nodes) ? NULL : \
+        list_entry((root)->nl_entry.dir, struct nouveau_mm_node, nl_entry)
 
 void
 nouveau_mm_put(struct nouveau_mm *rmm, struct nouveau_mm_node *this)
 {
-        u32 block_s, block_l;
+        struct nouveau_mm_node *prev = node(this, prev);
+        struct nouveau_mm_node *next = node(this, next);
 
-        this->free = true;
         list_add(&this->fl_entry, &rmm->free);
-        this = nouveau_mm_merge(rmm, this);
-
-        /* any entirely free blocks now?  we'll want to remove typing
-         * on them now so they can be use for any memory allocation
-         */
-        block_s = roundup(this->offset, rmm->block_size);
-        if (block_s + rmm->block_size > this->offset + this->length)
-                return;
+        this->type = 0;
 
-        /* split off any still-typed region at the start */
-        if (block_s != this->offset) {
-                if (!region_split(rmm, this, block_s - this->offset))
-                        return;
+        if (prev && prev->type == 0) {
+                prev->length += this->length;
+                region_put(rmm, this);
+                this = prev;
         }
 
-        /* split off the soon-to-be-untyped block(s) */
-        block_l = rounddown(this->length, rmm->block_size);
-        if (block_l != this->length) {
-                this = region_split(rmm, this, block_l);
-                if (!this)
-                        return;
+        if (next && next->type == 0) {
+                next->offset  = this->offset;
+                next->length += this->length;
+                region_put(rmm, this);
         }
-
-        /* mark as having no type, and retry merge with any adjacent
-         * untyped blocks
-         */
-        this->type = 0;
-        nouveau_mm_merge(rmm, this);
 }
 
 int
 nouveau_mm_get(struct nouveau_mm *rmm, int type, u32 size, u32 size_nc,
                u32 align, struct nouveau_mm_node **pnode)
 {
-        struct nouveau_mm_node *this, *tmp, *next;
-        u32 splitoff, avail, alloc;
-
-        list_for_each_entry_safe(this, tmp, &rmm->free, fl_entry) {
-                next = list_entry(this->nl_entry.next, struct nouveau_mm_node, nl_entry);
-                if (this->nl_entry.next == &rmm->nodes)
-                        next = NULL;
-
-                /* skip wrongly typed blocks */
-                if (this->type && this->type != type)
+        struct nouveau_mm_node *prev, *this, *next;
+        u32 min = size_nc ? size_nc : size;
+        u32 align_mask = align - 1;
+        u32 splitoff;
+        u32 s, e;
+
+        list_for_each_entry(this, &rmm->free, fl_entry) {
+                e = this->offset + this->length;
+                s = this->offset;
+
+                prev = node(this, prev);
+                if (prev && prev->type != type)
+                        s = roundup(s, rmm->block_size);
+
+                next = node(this, next);
+                if (next && next->type != type)
+                        e = rounddown(e, rmm->block_size);
+
+                s  = (s + align_mask) & ~align_mask;
+                e &= ~align_mask;
+                if (s > e || e - s < min)
                         continue;
 
-                /* account for alignment */
-                splitoff = this->offset & (align - 1);
-                if (splitoff)
-                        splitoff = align - splitoff;
-
-                if (this->length <= splitoff)
-                        continue;
-
-                /* determine total memory available from this, and
-                 * the next block (if appropriate)
-                 */
-                avail = this->length;
-                if (next && next->free && (!next->type || next->type == type))
-                        avail += next->length;
-
-                avail -= splitoff;
-
-                /* determine allocation size */
-                if (size_nc) {
-                        alloc = min(avail, size);
-                        alloc = rounddown(alloc, size_nc);
-                        if (alloc == 0)
-                                continue;
-                } else {
-                        alloc = size;
-                        if (avail < alloc)
-                                continue;
-                }
-
-                /* untyped block, split off a chunk that's a multiple
-                 * of block_size and type it
-                 */
-                if (!this->type) {
-                        u32 block = roundup(alloc + splitoff, rmm->block_size);
-                        if (this->length < block)
-                                continue;
-
-                        this = region_split(rmm, this, block);
-                        if (!this)
-                                return -ENOMEM;
-
-                        this->type = type;
-                }
-
-                /* stealing memory from adjacent block */
-                if (alloc > this->length) {
-                        u32 amount = alloc - (this->length - splitoff);
-
-                        if (!next->type) {
-                                amount = roundup(amount, rmm->block_size);
-
-                                next = region_split(rmm, next, amount);
-                                if (!next)
-                                        return -ENOMEM;
-
-                                next->type = type;
-                        }
-
-                        this->length += amount;
-                        next->offset += amount;
-                        next->length -= amount;
-                        if (!next->length) {
-                                list_del(&next->nl_entry);
-                                list_del(&next->fl_entry);
-                                kfree(next);
-                        }
-                }
-
-                if (splitoff) {
-                        if (!region_split(rmm, this, splitoff))
-                                return -ENOMEM;
-                }
+                splitoff = s - this->offset;
+                if (splitoff && !region_split(rmm, this, splitoff))
+                        return -ENOMEM;
 
-                this = region_split(rmm, this, alloc);
-                if (this == NULL)
+                this = region_split(rmm, this, min(size, e - s));
+                if (!this)
                         return -ENOMEM;
 
-                this->free = false;
+                this->type = type;
                 list_del(&this->fl_entry);
                 *pnode = this;
                 return 0;
@@ -234,7 +135,6 @@ nouveau_mm_init(struct nouveau_mm **prmm, u32 offset, u32 length, u32 block)
         heap = kzalloc(sizeof(*heap), GFP_KERNEL);
         if (!heap)
                 return -ENOMEM;
-        heap->free = true;
         heap->offset = roundup(offset, block);
         heap->length = rounddown(offset + length, block) - heap->offset;
 
diff --git a/drivers/gpu/drm/nouveau/nouveau_mm.h b/drivers/gpu/drm/nouveau/nouveau_mm.h
index af384493303..798eaf39691 100644
--- a/drivers/gpu/drm/nouveau/nouveau_mm.h
+++ b/drivers/gpu/drm/nouveau/nouveau_mm.h
@@ -30,9 +30,7 @@ struct nouveau_mm_node {
         struct list_head fl_entry;
         struct list_head rl_entry;
 
-        bool free;
-        int  type;
-
+        u8  type;
         u32 offset;
         u32 length;
 };