linux-kernel - [PATCH 2/2] drm/msm: Handle in-place remaps

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Message-ID: <20250723221213.36325-3-robin.clark@oss.qualcomm.com>
Date: Wed, 23 Jul 2025 15:12:12 -0700
From: Rob Clark <robin.clark@....qualcomm.com>
To: dri-devel@...ts.freedesktop.org
Cc: linux-arm-msm@...r.kernel.org, freedreno@...ts.freedesktop.org,
        Danilo Krummrich <dakr@...hat.com>,
        Connor Abbott <cwabbott0@...il.com>,
        Rob Clark <robin.clark@....qualcomm.com>,
        Dmitry Baryshkov <lumag@...nel.org>,
        Abhinav Kumar <abhinav.kumar@...ux.dev>,
        Jessica Zhang <jessica.zhang@....qualcomm.com>,
        Sean Paul <sean@...rly.run>,
        Marijn Suijten <marijn.suijten@...ainline.org>,
        David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
        linux-kernel@...r.kernel.org (open list)
Subject: [PATCH 2/2] drm/msm: Handle in-place remaps

Handle the special case of a MAP op simply updating the va flags by
detecting the special case, and skip pgtable updates.

Signed-off-by: Rob Clark <robin.clark@....qualcomm.com>
---
 drivers/gpu/drm/msm/msm_gem_vma.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/msm/msm_gem_vma.c b/drivers/gpu/drm/msm/msm_gem_vma.c
index dc54c693b28d..d4b1cfb3aa03 100644
--- a/drivers/gpu/drm/msm/msm_gem_vma.c
+++ b/drivers/gpu/drm/msm/msm_gem_vma.c
@@ -519,9 +519,10 @@ msm_gem_vm_sm_step_map(struct drm_gpuva_op *op, void *arg)
 }
 
 static int
-msm_gem_vm_sm_step_remap(struct drm_gpuva_op *op, void *arg)
+msm_gem_vm_sm_step_remap(struct drm_gpuva_op *op, void *_arg)
 {
-	struct msm_vm_bind_job *job = ((struct op_arg *)arg)->job;
+	struct op_arg *arg = _arg;
+	struct msm_vm_bind_job *job = arg->job;
 	struct drm_gpuvm *vm = job->vm;
 	struct drm_gpuva *orig_vma = op->remap.unmap->va;
 	struct drm_gpuva *prev_vma = NULL, *next_vma = NULL;
@@ -529,6 +530,18 @@ msm_gem_vm_sm_step_remap(struct drm_gpuva_op *op, void *arg)
 	bool mapped = to_msm_vma(orig_vma)->mapped;
 	unsigned flags;
 
+	/* Special case for in-place updates: */
+	if (op->remap.unmap->keep && arg->flags &&
+	    op->remap.next && !op->remap.prev &&
+	    (orig_vma->gem.obj == op->remap.next->gem.obj) &&
+	    (orig_vma->gem.offset == op->remap.next->gem.offset) &&
+	    (orig_vma->va.addr == op->remap.next->va.addr) &&
+	    (orig_vma->va.range == op->remap.next->va.range)) {
+		/* Only flags are changing, so update that in-place: */
+		unsigned orig_flags = orig_vma->flags & (DRM_GPUVA_USERBITS - 1);
+		orig_vma->flags |= orig_flags | arg->flags;
+	}
+
 	vm_dbg("orig_vma: %p:%p:%p: %016llx %016llx", vm, orig_vma,
 	       orig_vma->gem.obj, orig_vma->va.addr, orig_vma->va.range);
 
-- 
2.50.1