The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From bf8975837dac156c33a4d15d46602700998cb6dd Mon Sep 17 00:00:00 2001
From: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
Date: Tue, 24 Nov 2020 12:57:07 +0100
Subject: [PATCH] dma-buf/dma-resv: Respect num_fences when initializing the
shared fence list.
MIME-Version: 1.0
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We hardcode the maximum number of shared fences to 4, instead of
respecting num_fences. Use a minimum of 4, but more if num_fences
is higher.
This seems to have been an oversight when first implementing the
api.
Fixes: 04a5faa8cbe5 ("reservation: update api and add some helpers")
Cc: <stable@xxxxxxxxxxxxxxx> # v3.17+
Reported-by: Niranjana Vishwanathapura <niranjana.vishwanathapura@xxxxxxxxx>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
Reviewed-by: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20201124115707.406917-1-maarten.lankhorst@xxxxxxxxxxxxxxx
diff --git a/drivers/dma-buf/dma-resv.c b/drivers/dma-buf/dma-resv.c
index bb5a42b10c29..6ddbeb5dfbf6 100644
--- a/drivers/dma-buf/dma-resv.c
+++ b/drivers/dma-buf/dma-resv.c
@@ -200,7 +200,7 @@ int dma_resv_reserve_shared(struct dma_resv *obj, unsigned int num_fences)
max = max(old->shared_count + num_fences,
old->shared_max * 2);
} else {
- max = 4;
+ max = max(4ul, roundup_pow_of_two(num_fences));
}
new = dma_resv_list_alloc(max);
