x86/amd_node: Fix PCI device reference counting in amd_smn_init()grafted

The local "root" pointer is a temporary variable used during the device
search. Therefore, refcount related to the search iterators should be cleaned
up after the search is complete.

Use the __free() cleanup macro to ensure the refcount is decremented when the
temporary pointer goes out of scope.

Additionally, increment the refcount when caching a root pointer. This ensures
the in-use refcount is separate from the temporary search refcounting.

Finally, drop the redundant "root = NULL" before the second search loop. The
pci_get_class() iterator always decrements the refcount of its "from"
argument, so the first loop can only fall through with "root" already NULL.

Fixes: 0a4b61d9c2e4 ("x86/amd_node: Fix AMD root device caching")
Closes: https://sashiko.dev/#/patchset/20260806160159.230453-1-jason.andryuk%40amd.com
Reported-by: Sashiko <sashiko-bot@kernel.org>
Assisted-by: LLM
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Cc: <stable@kernel.org>
Link: https://patch.msgid.link/20260903154325.74343-1-yazen.ghannam@amd.com

1 files changed, 40 insertions, 0 deletions

diff --git a/include/crypto/internal/simd.h b/include/crypto/internal/simd.h
new file mode 100644
index 000000000..f5e5d7b63
--- /dev/null
+++ b/include/crypto/internal/simd.h
@@ -0,0 +1,40 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Shared crypto simd helpers
+ */
+
+#ifndef _CRYPTO_INTERNAL_SIMD_H
+#define _CRYPTO_INTERNAL_SIMD_H
+
+#include <asm/simd.h>
+#include <linux/percpu.h>
+#include <linux/types.h>
+
+struct simd_aead_alg;
+struct aead_alg;
+
+int simd_register_aeads_compat(struct aead_alg *algs, int count,
+			       struct simd_aead_alg **simd_algs);
+
+void simd_unregister_aeads(struct aead_alg *algs, int count,
+			   struct simd_aead_alg **simd_algs);
+
+/*
+ * crypto_simd_usable() - is it allowed at this time to use SIMD instructions or
+ *			  access the SIMD register file?
+ *
+ * This delegates to may_use_simd(), except that this also returns false if SIMD
+ * in crypto code has been temporarily disabled on this CPU by the crypto
+ * self-tests, in order to test the no-SIMD fallback code.  This override is
+ * currently limited to configurations where the "full" self-tests are enabled,
+ * because it might be a bit too invasive to be part of the "fast" self-tests.
+ */
+#ifdef CONFIG_CRYPTO_SELFTESTS_FULL
+DECLARE_PER_CPU(bool, crypto_simd_disabled_for_test);
+#define crypto_simd_usable() \
+	(may_use_simd() && !this_cpu_read(crypto_simd_disabled_for_test))
+#else
+#define crypto_simd_usable() may_use_simd()
+#endif
+
+#endif /* _CRYPTO_INTERNAL_SIMD_H */