drm/i915: Replace kmap() with kmap_local_page()

kmap() has been deprecated in favor of the kmap_local_page()
due to high cost, restricted mapping space, the overhead of a
global lock for synchronization, and making the process sleep
in the absence of free slots.

kmap_local_page() is faster than kmap() and offers thread-local
and CPU-local mappings, can take pagefaults in a local kmap region
and preserves preemption by saving the mappings of outgoing tasks
and restoring those of the incoming one during a context switch.

The mapping is kept thread local in the function
“i915_vma_coredump_create” in i915_gpu_error.c

Therefore, replace kmap() with kmap_local_page().

Suggested-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Sumitra Sharma <sumitraartsy@gmail.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230617180420.GA410966@sumitra.com
[tursulin: Removed blank line within tags. Fixup commit text.]

diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c
index ec368e7..4749f99 100644 (file)
--- a/drivers/gpu/drm/i915/i915_gpu_error.c
+++ b/drivers/gpu/drm/i915/i915_gpu_error.c
@@ -1173,9 +1173,9 @@ i915_vma_coredump_create(const struct intel_gt *gt,
 
                        drm_clflush_pages(&page, 1);
 
-                       s = kmap(page);
+                       s = kmap_local_page(page);
                        ret = compress_page(compress, s, dst, false);
-                       kunmap(page);
+                       kunmap_local(s);
 
                        drm_clflush_pages(&page, 1);