git: b4d3dd861511 - main - zfs: fix up bogus checksums with blake3 in face of cpu migration

The branch main has been updated by mjg:

URL: https://cgit.FreeBSD.org/src/commit/?id=b4d3dd861511cc58c1d1328511189b8a42a6d091

commit b4d3dd861511cc58c1d1328511189b8a42a6d091
Author:     Mateusz Guzik <mjg@FreeBSD.org>
AuthorDate: 2023-04-25 15:20:19 +0000
Commit:     Mateusz Guzik <mjg@FreeBSD.org>
CommitDate: 2023-04-25 15:20:19 +0000

    zfs: fix up bogus checksums with blake3 in face of cpu migration
    
    This is a temporary measure until a better fix is sorted out.
    
    Upstream report: https://github.com/openzfs/zfs/issues/14785
    Reported by:    Evgeniy Khramtsov
    Sponsored by:   Rubicon Communications, LLC ("Netgate")
---
 sys/contrib/openzfs/module/zfs/blake3_zfs.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/sys/contrib/openzfs/module/zfs/blake3_zfs.c b/sys/contrib/openzfs/module/zfs/blake3_zfs.c
index bcc595bca8f2..7783282b671a 100644
--- a/sys/contrib/openzfs/module/zfs/blake3_zfs.c
+++ b/sys/contrib/openzfs/module/zfs/blake3_zfs.c
@@ -50,7 +50,8 @@ abd_checksum_blake3_native(abd_t *abd, uint64_t size, const void *ctx_template,
 	ASSERT(ctx_template != NULL);
 
 #if defined(_KERNEL)
-	BLAKE3_CTX *ctx = blake3_per_cpu_ctx[CPU_SEQID_UNSTABLE];
+	kpreempt_disable();
+	BLAKE3_CTX *ctx = blake3_per_cpu_ctx[CPU_SEQID];
 #else
 	BLAKE3_CTX *ctx = kmem_alloc(sizeof (*ctx), KM_SLEEP);
 #endif
@@ -59,7 +60,9 @@ abd_checksum_blake3_native(abd_t *abd, uint64_t size, const void *ctx_template,
 	(void) abd_iterate_func(abd, 0, size, blake3_incremental, ctx);
 	Blake3_Final(ctx, (uint8_t *)zcp);
 
-#if !defined(_KERNEL)
+#if defined(_KERNEL)
+	kpreempt_enable();
+#else
 	memset(ctx, 0, sizeof (*ctx));
 	kmem_free(ctx, sizeof (*ctx));
 #endif