drm/i915: Replace kmap() with kmap_local_page()
authorSumitra Sharma <sumitraartsy@gmail.com>
Sat, 17 Jun 2023 18:04:20 +0000 (11:04 -0700)
committerTvrtko Ursulin <tvrtko.ursulin@intel.com>
Mon, 26 Jun 2023 08:12:52 +0000 (09:12 +0100)
commit36dd2a6e5003a215a1d45e41589164dabae0ec5a
tree4fb1f9327a156d65f36cda83ba9301c97b1babe2
parent6580176fd04331130d94de3022c5eab97dee577e
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.]
drivers/gpu/drm/i915/i915_gpu_error.c