drm/nouveau/imem/nv50: move slow-path locking into rd/wr functions

This is to simplify upcoming changes.  The slow-path is something that
currently occurs during bootstrap of the BAR2 VMM, while backing up an
object during suspend/resume, or when BAR2 address space runs out.

The latter is a real problem that can happen at runtime, and occurs in
Fedora 26 already (due to some change that causes a lot of channels to
be created at login), so ideally we'd prefer not to make it any slower.

We'd also like suspend/resume speed to not suffer.

Upcoming commits will solve those problems in a better way, making the
extra overhead of moving the locking here a non-issue.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/instmem/nv50.c b/drivers/gpu/drm/nouveau/nvkm/subdev/instmem/nv50.c
index 95b2c56..d0159d5 100644 (file)
--- a/drivers/gpu/drm/nouveau/nvkm/subdev/instmem/nv50.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/instmem/nv50.c
@@ -31,8 +31,6 @@
 
 struct nv50_instmem {
        struct nvkm_instmem base;
-       unsigned long lock_flags;
-       spinlock_t lock;
        u64 addr;
 };
 
@@ -57,12 +55,15 @@ nv50_instobj_wr32_slow(struct nvkm_memory *memory, u64 offset, u32 data)
        struct nvkm_device *device = imem->base.subdev.device;
        u64 base = (iobj->mem->offset + offset) & 0xffffff00000ULL;
        u64 addr = (iobj->mem->offset + offset) & 0x000000fffffULL;
+       unsigned long flags;
 
+       spin_lock_irqsave(&imem->base.lock, flags);
        if (unlikely(imem->addr != base)) {
                nvkm_wr32(device, 0x001700, base >> 16);
                imem->addr = base;
        }
        nvkm_wr32(device, 0x700000 + addr, data);
+       spin_unlock_irqrestore(&imem->base.lock, flags);
 }
 
 static u32
@@ -74,12 +75,15 @@ nv50_instobj_rd32_slow(struct nvkm_memory *memory, u64 offset)
        u64 base = (iobj->mem->offset + offset) & 0xffffff00000ULL;
        u64 addr = (iobj->mem->offset + offset) & 0x000000fffffULL;
        u32 data;
+       unsigned long flags;
 
+       spin_lock_irqsave(&imem->base.lock, flags);
        if (unlikely(imem->addr != base)) {
                nvkm_wr32(device, 0x001700, base >> 16);
                imem->addr = base;
        }
        data = nvkm_rd32(device, 0x700000 + addr);
+       spin_unlock_irqrestore(&imem->base.lock, flags);
        return data;
 }
 
@@ -127,8 +131,6 @@ nv50_instobj_map(struct nvkm_memory *memory, struct nvkm_vma *vma, u64 offset)
 static void
 nv50_instobj_release(struct nvkm_memory *memory)
 {
-       struct nv50_instmem *imem = nv50_instobj(memory)->imem;
-       spin_unlock_irqrestore(&imem->lock, imem->lock_flags);
 }
 
 static void __iomem *
@@ -137,15 +139,12 @@ nv50_instobj_acquire(struct nvkm_memory *memory)
        struct nv50_instobj *iobj = nv50_instobj(memory);
        struct nv50_instmem *imem = iobj->imem;
        struct nvkm_vm *vm;
-       unsigned long flags;
 
        if (!iobj->map && (vm = nvkm_bar_bar2_vmm(imem->base.subdev.device)))
                nv50_instobj_kmap(iobj, vm);
        if (!IS_ERR_OR_NULL(iobj->map))
                return iobj->map;
 
-       spin_lock_irqsave(&imem->lock, flags);
-       imem->lock_flags = flags;
        return NULL;
 }
 
@@ -254,7 +253,6 @@ nv50_instmem_new(struct nvkm_device *device, int index,
        if (!(imem = kzalloc(sizeof(*imem), GFP_KERNEL)))
                return -ENOMEM;
        nvkm_instmem_ctor(&nv50_instmem, device, index, &imem->base);
-       spin_lock_init(&imem->lock);
        *pimem = &imem->base;
        return 0;
 }