Revert "kmsan: unpoison @tlb in arch_tlb_gather_mmu()"

This reverts commit ac801e7e252c5588325e3c983c7d4167fc68c024.

The patch in question was picked to -mm from the KMSAN v6 patch series
(https://lore.kernel.org/linux-mm/[email protected]/)
and sneaked into mainline despite its removal from the v7 series
(https://lore.kernel.org/linux-mm/[email protected]/)

Currently KMSAN does not warn about origin chains hitting the maximum
depth, so keeping @tlb poisoned won't result in any inconveniences.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Alexander Potapenko <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Eric Biggers <[email protected]>
Cc: Marco Elver <[email protected]>
Cc: Peter Zijlstra (Intel) <[email protected]>
Cc: Will Deacon <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

1 files changed, 0 insertions, 10 deletions

diff --git a/mm/mmu_gather.c b/mm/mmu_gather.c
index dd1f8ca40cb5..8247553a69c2 100644
--- a/mm/mmu_gather.c
+++ b/mm/mmu_gather.c
@@ -1,7 +1,6 @@
 #include <linux/gfp.h>
 #include <linux/highmem.h>
 #include <linux/kernel.h>
-#include <linux/kmsan-checks.h>
 #include <linux/mmdebug.h>
 #include <linux/mm_types.h>
 #include <linux/mm_inline.h>
@@ -299,15 +298,6 @@ void tlb_flush_mmu(struct mmu_gather *tlb)
 static void __tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm,
 			     bool fullmm)
 {
-	/*
-	 * struct mmu_gather contains 7 1-bit fields packed into a 32-bit
-	 * unsigned int value. The remaining 25 bits remain uninitialized
-	 * and are never used, but KMSAN updates the origin for them in
-	 * zap_pXX_range() in mm/memory.c, thus creating very long origin
-	 * chains. This is technically correct, but consumes too much memory.
-	 * Unpoisoning the whole structure will prevent creating such chains.
-	 */
-	kmsan_unpoison_memory(tlb, sizeof(*tlb));
 	tlb->mm = mm;
 	tlb->fullmm = fullmm;