From 7d5553147613b50149238ac1385c60e5c7cacb34 Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Wed, 16 Sep 2020 10:00:58 +0100
Subject: [PATCH] drm/i915: Break up error capture compression loops with cond_resched()
Git-commit: 7d5553147613b50149238ac1385c60e5c7cacb34
Patch-mainline: v5.10-rc1
No-fix: 293f43c80c0027ff9299036c24218ac705ce584e
References: git-fixes

As the error capture will compress user buffers as directed to by the
user, it can take an arbitrary amount of time and space. Break up the
compression loops with a call to cond_resched(), that will allow other
processes to schedule (avoiding the soft lockups) and also serve as a
warning should we try to make this loop atomic in the future.

Testcase: igt/gem_exec_capture/many-*
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: stable@vger.kernel.org
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200916090059.3189-2-chris@chris-wilson.co.uk
(cherry picked from commit 293f43c80c0027ff9299036c24218ac705ce584e)

Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/gpu/drm/i915/i915_gpu_error.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/gpu/drm/i915/i915_gpu_error.c
+++ b/drivers/gpu/drm/i915/i915_gpu_error.c
@@ -268,6 +268,8 @@ static int compress_page(struct compress
 
 		if (zlib_deflate(zstream, Z_NO_FLUSH) != Z_OK)
 			return -EIO;
+
+		cond_resched();
 	} while (zstream->avail_in);
 
 	/* Fallback to uncompressed if we increase size? */
@@ -347,6 +349,7 @@ static int compress_page(struct compress
 	if (!i915_memcpy_from_wc(ptr, src, PAGE_SIZE))
 		memcpy(ptr, src, PAGE_SIZE);
 	dst->pages[dst->page_count++] = ptr;
+	cond_resched();
 
 	return 0;
 }