The final call to zlib_deflate(Z_FINISH) may require more output space to be allocated and so needs to re-invoked. Failure to do so in the current code leads to incomplete zlib streams (albeit intact due to the use of Z_SYNC_FLUSH) resulting in the occasional short object capture.

Testcase: igt/i915-error-capture.js Fixes: 0a97015d45ee ("drm/i915: Compress GPU objects in error state") Signed-off-by: Chris Wilson chris@chris-wilson.co.uk Cc: Joonas Lahtinen joonas.lahtinen@linux.intel.com Cc: stable@vger.kernel.org # v4.10+ --- drivers/gpu/drm/i915/i915_gpu_error.c | 60 +++++++++++++++++++++------ 1 file changed, 47 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c index 2835cacd0d08..9789f4ff8c32 100644 --- a/drivers/gpu/drm/i915/i915_gpu_error.c +++ b/drivers/gpu/drm/i915/i915_gpu_error.c @@ -237,6 +237,7 @@ static int compress_page(struct compress *c, struct drm_i915_error_object *dst) { struct z_stream_s *zstream = &c->zstream; + int flush = Z_NO_FLUSH;

zstream->next_in = src; if (c->tmp && i915_memcpy_from_wc(c->tmp, src, PAGE_SIZE)) @@ -257,8 +258,11 @@ static int compress_page(struct compress *c, zstream->avail_out = PAGE_SIZE; }

- if (zlib_deflate(zstream, Z_SYNC_FLUSH) != Z_OK) + if (zlib_deflate(zstream, flush) != Z_OK) return -EIO; + + if (zstream->avail_out) + flush = Z_SYNC_FLUSH; } while (zstream->avail_in);

/* Fallback to uncompressed if we increase size? */ @@ -268,19 +272,43 @@ static int compress_page(struct compress *c, return 0; }

-static void compress_fini(struct compress *c, +static int compress_flush(struct compress *c, struct drm_i915_error_object *dst) { struct z_stream_s *zstream = &c->zstream; + unsigned long page;

- if (dst) { - zlib_deflate(zstream, Z_FINISH); - dst->unused = zstream->avail_out; - } + do { + switch (zlib_deflate(zstream, Z_FINISH)) { + case Z_OK: /* more space requested */ + page = __get_free_page(GFP_ATOMIC | __GFP_NOWARN); + if (!page) + return -ENOMEM; + + dst->pages[dst->page_count++] = (void *)page; + zstream->next_out = (void *)page; + zstream->avail_out = PAGE_SIZE; + break; + case Z_STREAM_END: + goto end; + default: /* any error */ + return -EIO; + } + } while (1); + +end: + memset(zstream->next_out, 0, zstream->avail_out); + dst->unused = zstream->avail_out; + return 0; +} + +static void compress_fini(struct compress *c, + struct drm_i915_error_object *dst) +{ + struct z_stream_s *zstream = &c->zstream;

zlib_deflateEnd(zstream); kfree(zstream->workspace); - if (c->tmp) free_page((unsigned long)c->tmp); } @@ -319,6 +347,12 @@ static int compress_page(struct compress *c, return 0; }

+static int compress_flush(struct compress *c, + struct drm_i915_error_object *dst) +{ + return 0; +} + static void compress_fini(struct compress *c, struct drm_i915_error_object *dst) { @@ -951,15 +985,15 @@ i915_error_object_create(struct drm_i915_private *i915, if (ret) goto unwind; } - goto out;

+ if (compress_flush(&compress, dst)) { unwind: - while (dst->page_count--) - free_page((unsigned long)dst->pages[dst->page_count]); - kfree(dst); - dst = NULL; + while (dst->page_count--) + free_page((unsigned long)dst->pages[dst->page_count]); + kfree(dst); + dst = NULL; + }

-out: compress_fini(&compress, dst); ggtt->vm.clear_range(&ggtt->vm, slot, PAGE_SIZE); return dst;