This is a note to let you know that I've just added the patch titled
drm/panfrost: Don't try to map pages that are already mapped
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-panfrost-don-t-try-to-map-pages-that-are-already-mapped.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From f45da8204ff1707c529a8769f5467ff16f504b26 Mon Sep 17 00:00:00 2001
From: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>
Date: Fri, 5 Feb 2021 12:17:56 +0100
Subject: drm/panfrost: Don't try to map pages that are already mapped
From: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>
commit f45da8204ff1707c529a8769f5467ff16f504b26 upstream.
We allocate 2MB chunks at a time, so it might appear that a page fault
has already been handled by a previous page fault when we reach
panfrost_mmu_map_fault_addr(). Bail out in that case to avoid mapping the
same area twice.
Cc: <stable@xxxxxxxxxxxxxxx>
Fixes: 187d2929206e ("drm/panfrost: Add support for GPU heap allocations")
Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>
Reviewed-by: Steven Price <steven.price@xxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20210205111757.585248-3-boris.brezillon@xxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/panfrost/panfrost_mmu.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
--- a/drivers/gpu/drm/panfrost/panfrost_mmu.c
+++ b/drivers/gpu/drm/panfrost/panfrost_mmu.c
@@ -494,8 +494,14 @@ static int panfrost_mmu_map_fault_addr(s
}
bo->base.pages = pages;
bo->base.pages_use_count = 1;
- } else
+ } else {
pages = bo->base.pages;
+ if (pages[page_offset]) {
+ /* Pages are already mapped, bail out. */
+ mutex_unlock(&bo->base.pages_lock);
+ goto out;
+ }
+ }
mapping = bo->base.base.filp->f_mapping;
mapping_set_unevictable(mapping);
@@ -529,6 +535,7 @@ static int panfrost_mmu_map_fault_addr(s
dev_dbg(pfdev->dev, "mapped page fault @ AS%d %llx", as, addr);
+out:
panfrost_gem_mapping_put(bomapping);
return 0;
Patches currently in stable-queue which might be from boris.brezillon@xxxxxxxxxxxxx are
queue-5.4/drm-panfrost-don-t-try-to-map-pages-that-are-already-mapped.patch
queue-5.4/drm-panfrost-clear-mmu-irqs-before-handling-the-fault.patch
