Re: [Intel-gfx] [PATCH 2/8] drm/i915/gt: Refactor _wa_add to reuse wa_index and wa_list_grow

[Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>]

This is quite different and much cleane from my original patch :), so 
you should be the author. With that, this is

Reviewed-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>

Thanks,
Umesh

On Tue, Nov 17, 2020 at 11:01:26AM +0000, Chris Wilson wrote:
>From: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
>
>Switch the search and grow code of the _wa_add to use _wa_index and
>_wa_list_grow.
>
>Signed-off-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
>---
> drivers/gpu/drm/i915/gt/intel_workarounds.c | 124 +++++++++++---------
> 1 file changed, 71 insertions(+), 53 deletions(-)
>
>diff --git a/drivers/gpu/drm/i915/gt/intel_workarounds.c b/drivers/gpu/drm/i915/gt/intel_workarounds.c
>index c49083957074..e50c72d2b3f1 100644
>--- a/drivers/gpu/drm/i915/gt/intel_workarounds.c
>+++ b/drivers/gpu/drm/i915/gt/intel_workarounds.c
>@@ -91,20 +91,19 @@ static void wa_init_start(struct i915_wa_list *wal, const char *name, const char
>
> #define WA_LIST_CHUNK (1 << 4)
>
>-static void wa_init_finish(struct i915_wa_list *wal)
>+static void wa_trim(struct i915_wa_list *wal, gfp_t gfp)
> {
>+	struct i915_wa *list;
>+
> 	/* Trim unused entries. */
>-	if (!IS_ALIGNED(wal->count, WA_LIST_CHUNK)) {
>-		struct i915_wa *list = kmemdup(wal->list,
>-					       wal->count * sizeof(*list),
>-					       GFP_KERNEL);
>-
>-		if (list) {
>-			kfree(wal->list);
>-			wal->list = list;
>-		}
>-	}
>+	list = krealloc(wal->list, wal->count * sizeof(*list), gfp);
>+	if (list)
>+		wal->list = list;
>+}
>
>+static void wa_init_finish(struct i915_wa_list *wal)
>+{
>+	wa_trim(wal, GFP_KERNEL);
> 	if (!wal->count)
> 		return;
>
>@@ -112,57 +111,60 @@ static void wa_init_finish(struct i915_wa_list *wal)
> 			 wal->wa_count, wal->name, wal->engine_name);
> }
>
>-static void _wa_add(struct i915_wa_list *wal, const struct i915_wa *wa)
>+static int wa_index(struct i915_wa_list *wal, i915_reg_t reg)
> {
>-	unsigned int addr = i915_mmio_reg_offset(wa->reg);
>-	unsigned int start = 0, end = wal->count;
>-	const unsigned int grow = WA_LIST_CHUNK;
>-	struct i915_wa *wa_;
>+	unsigned int addr = i915_mmio_reg_offset(reg);
>+	int start = 0, end = wal->count;
>
>-	GEM_BUG_ON(!is_power_of_2(grow));
>+	/* addr and wal->list[].reg, both include the R/W flags */
>+	while (start < end) {
>+		unsigned int mid = start + (end - start) / 2;
>
>-	if (IS_ALIGNED(wal->count, grow)) { /* Either uninitialized or full. */
>-		struct i915_wa *list;
>+		if (i915_mmio_reg_offset(wal->list[mid].reg) < addr)
>+			start = mid + 1;
>+		else if (i915_mmio_reg_offset(wal->list[mid].reg) > addr)
>+			end = mid;
>+		else
>+			return mid;
>+	}
>
>-		list = kmalloc_array(ALIGN(wal->count + 1, grow), sizeof(*wa),
>-				     GFP_KERNEL);
>-		if (!list) {
>-			DRM_ERROR("No space for workaround init!\n");
>-			return;
>-		}
>+	return -ENOENT;
>+}
>
>-		if (wal->list) {
>-			memcpy(list, wal->list, sizeof(*wa) * wal->count);
>-			kfree(wal->list);
>-		}
>+static int wa_list_grow(struct i915_wa_list *wal, size_t count, gfp_t gfp)
>+{
>+	struct i915_wa *list;
>
>-		wal->list = list;
>-	}
>+	list = krealloc(wal->list, count * sizeof(*list), gfp);
>+	if (!list)
>+		return -ENOMEM;
>
>-	while (start < end) {
>-		unsigned int mid = start + (end - start) / 2;
>+	wal->list = list;
>+	return 0;
>+}
>
>-		if (i915_mmio_reg_offset(wal->list[mid].reg) < addr) {
>-			start = mid + 1;
>-		} else if (i915_mmio_reg_offset(wal->list[mid].reg) > addr) {
>-			end = mid;
>-		} else {
>-			wa_ = &wal->list[mid];
>-
>-			if ((wa->clr | wa_->clr) && !(wa->clr & ~wa_->clr)) {
>-				DRM_ERROR("Discarding overwritten w/a for reg %04x (clear: %08x, set: %08x)\n",
>-					  i915_mmio_reg_offset(wa_->reg),
>-					  wa_->clr, wa_->set);
>-
>-				wa_->set &= ~wa->clr;
>-			}
>-
>-			wal->wa_count++;
>-			wa_->set |= wa->set;
>-			wa_->clr |= wa->clr;
>-			wa_->read |= wa->read;
>-			return;
>+static void __wa_add(struct i915_wa_list *wal, const struct i915_wa *wa)
>+{
>+	struct i915_wa *wa_;
>+	int index;
>+
>+	index = wa_index(wal, wa->reg);
>+	if (index >= 0) {
>+		wa_ = &wal->list[index];
>+
>+		if ((wa->clr | wa_->clr) && !(wa->clr & ~wa_->clr)) {
>+			DRM_ERROR("Discarding overwritten w/a for reg %04x (clear: %08x, set: %08x)\n",
>+				  i915_mmio_reg_offset(wa_->reg),
>+				  wa_->clr, wa_->set);
>+
>+			wa_->set &= ~wa->clr;
> 		}
>+
>+		wal->wa_count++;
>+		wa_->set |= wa->set;
>+		wa_->clr |= wa->clr;
>+		wa_->read |= wa->read;
>+		return;
> 	}
>
> 	wal->wa_count++;
>@@ -180,6 +182,22 @@ static void _wa_add(struct i915_wa_list *wal, const struct i915_wa *wa)
> 	}
> }
>
>+static void _wa_add(struct i915_wa_list *wal, const struct i915_wa *wa)
>+{
>+	const unsigned int grow = WA_LIST_CHUNK;
>+
>+	GEM_BUG_ON(!is_power_of_2(grow));
>+
>+	if (IS_ALIGNED(wal->count, grow) && /* Either uninitialized or full. */
>+	    wa_list_grow(wal, ALIGN(wal->count + 1, grow), GFP_KERNEL)) {
>+		DRM_ERROR("Unable to store w/a for reg %04x\n",
>+			  i915_mmio_reg_offset(wa->reg));
>+		return;
>+	}
>+
>+	__wa_add(wal, wa);
>+}
>+
> static void wa_add(struct i915_wa_list *wal, i915_reg_t reg,
> 		   u32 clear, u32 set, u32 read_mask)
> {
>-- 
>2.20.1
>
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