linux-kernel - [PATCH 2/3] drm/msm: Allocate memory for disp snapshot with kvzalloc()

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Message-ID: <20241014093605.2.I72441365ffe91f3dceb17db0a8ec976af8139590@changeid>
Date: Mon, 14 Oct 2024 09:36:09 -0700
From: Douglas Anderson <dianders@...omium.org>
To: Rob Clark <robdclark@...il.com>,
	Abhinav Kumar <quic_abhinavk@...cinc.com>,
	Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
Cc: Stephen Boyd <swboyd@...omium.org>,
	Douglas Anderson <dianders@...omium.org>,
	David Airlie <airlied@...il.com>,
	Marijn Suijten <marijn.suijten@...ainline.org>,
	Sean Paul <sean@...rly.run>,
	Simona Vetter <simona@...ll.ch>,
	dri-devel@...ts.freedesktop.org,
	freedreno@...ts.freedesktop.org,
	linux-arm-msm@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH 2/3] drm/msm: Allocate memory for disp snapshot with kvzalloc()

With the "drm/msm: add a display mmu fault handler" series [1] we saw
issues in the field where memory allocation was failing when
allocating space for registers in msm_disp_state_dump_regs().
Specifically we were seeing an order 5 allocation fail. It's not
surprising that order 5 allocations will sometimes fail after the
system has been up and running for a while.

There's no need here for contiguous memory. Change the allocation to
kvzalloc() which should make it much less likely to fail.

[1] https://lore.kernel.org/r/20240628214848.4075651-1-quic_abhinavk@quicinc.com/

Fixes: 98659487b845 ("drm/msm: add support to take dpu snapshot")
Signed-off-by: Douglas Anderson <dianders@...omium.org>
---

 drivers/gpu/drm/msm/disp/msm_disp_snapshot_util.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/msm/disp/msm_disp_snapshot_util.c b/drivers/gpu/drm/msm/disp/msm_disp_snapshot_util.c
index bb149281d31f..4d55e3cf570f 100644
--- a/drivers/gpu/drm/msm/disp/msm_disp_snapshot_util.c
+++ b/drivers/gpu/drm/msm/disp/msm_disp_snapshot_util.c
@@ -26,7 +26,7 @@ static void msm_disp_state_dump_regs(u32 **reg, u32 aligned_len, void __iomem *b
 	end_addr = base_addr + aligned_len;
 
 	if (!(*reg))
-		*reg = kzalloc(len_padded, GFP_KERNEL);
+		*reg = kvzalloc(len_padded, GFP_KERNEL);
 
 	if (*reg)
 		dump_addr = *reg;
@@ -162,7 +162,7 @@ void msm_disp_state_free(void *data)
 
 	list_for_each_entry_safe(block, tmp, &disp_state->blocks, node) {
 		list_del(&block->node);
-		kfree(block->state);
+		kvfree(block->state);
 		kfree(block);
 	}
 
-- 
2.47.0.rc1.288.g06298d1525-goog