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, 246 insertions, 0 deletions

diff --git a/include/crypto/internal/acompress.h b/include/crypto/internal/acompress.h
new file mode 100644
index 000000000..9cd37df32
--- /dev/null
+++ b/include/crypto/internal/acompress.h
@@ -0,0 +1,246 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Asynchronous Compression operations
+ *
+ * Copyright (c) 2016, Intel Corporation
+ * Authors: Weigang Li <weigang.li@intel.com>
+ *          Giovanni Cabiddu <giovanni.cabiddu@intel.com>
+ */
+#ifndef _CRYPTO_ACOMP_INT_H
+#define _CRYPTO_ACOMP_INT_H
+
+#include <crypto/acompress.h>
+#include <crypto/algapi.h>
+#include <crypto/scatterwalk.h>
+#include <linux/compiler_types.h>
+#include <linux/cpumask_types.h>
+#include <linux/spinlock.h>
+#include <linux/workqueue_types.h>
+
+#define ACOMP_FBREQ_ON_STACK(name, req) \
+        char __##name##_req[sizeof(struct acomp_req) + \
+                            MAX_SYNC_COMP_REQSIZE] CRYPTO_MINALIGN_ATTR; \
+        struct acomp_req *name = acomp_fbreq_on_stack_init( \
+                __##name##_req, (req))
+
+/**
+ * struct acomp_alg - asynchronous compression algorithm
+ *
+ * @compress:	Function performs a compress operation
+ * @decompress:	Function performs a de-compress operation
+ * @init:	Initialize the cryptographic transformation object.
+ *		This function is used to initialize the cryptographic
+ *		transformation object. This function is called only once at
+ *		the instantiation time, right after the transformation context
+ *		was allocated. In case the cryptographic hardware has some
+ *		special requirements which need to be handled by software, this
+ *		function shall check for the precise requirement of the
+ *		transformation and put any software fallbacks in place.
+ * @exit:	Deinitialize the cryptographic transformation object. This is a
+ *		counterpart to @init, used to remove various changes set in
+ *		@init.
+ *
+ * @base:	Common crypto API algorithm data structure
+ * @calg:	Cmonn algorithm data structure shared with scomp
+ * @COMP_ALG_COMMON: see struct comp_alg_common
+ */
+struct acomp_alg {
+	int (*compress)(struct acomp_req *req);
+	int (*decompress)(struct acomp_req *req);
+	int (*init)(struct crypto_acomp *tfm);
+	void (*exit)(struct crypto_acomp *tfm);
+
+	union {
+		struct COMP_ALG_COMMON;
+		struct comp_alg_common calg;
+	};
+};
+
+struct crypto_acomp_stream {
+	spinlock_t lock;
+	void *ctx;
+};
+
+struct crypto_acomp_streams {
+	/* These must come first because of struct scomp_alg. */
+	void *(*alloc_ctx)(void);
+	void (*free_ctx)(void *);
+
+	struct crypto_acomp_stream __percpu *streams;
+	struct work_struct stream_work;
+	cpumask_t stream_want;
+};
+
+struct acomp_walk {
+	union {
+		/* Virtual address of the source. */
+		struct {
+			struct {
+				const void *const addr;
+			} virt;
+		} src;
+
+		/* Private field for the API, do not use. */
+		struct scatter_walk in;
+	};
+
+	union {
+		/* Virtual address of the destination. */
+		struct {
+			struct {
+				void *const addr;
+			} virt;
+		} dst;
+
+		/* Private field for the API, do not use. */
+		struct scatter_walk out;
+	};
+
+	unsigned int slen;
+	unsigned int dlen;
+
+	int flags;
+};
+
+/*
+ * Transform internal helpers.
+ */
+static inline void *acomp_request_ctx(struct acomp_req *req)
+{
+	return req->__ctx;
+}
+
+static inline void *acomp_tfm_ctx(struct crypto_acomp *tfm)
+{
+	return tfm->base.__crt_ctx;
+}
+
+static inline void acomp_request_complete(struct acomp_req *req,
+					  int err)
+{
+	crypto_request_complete(&req->base, err);
+}
+
+/**
+ * crypto_register_acomp() -- Register asynchronous compression algorithm
+ *
+ * Function registers an implementation of an asynchronous
+ * compression algorithm
+ *
+ * @alg:	algorithm definition
+ *
+ * Return:	zero on success; error code in case of error
+ */
+int crypto_register_acomp(struct acomp_alg *alg);
+
+/**
+ * crypto_unregister_acomp() -- Unregister asynchronous compression algorithm
+ *
+ * Function unregisters an implementation of an asynchronous
+ * compression algorithm
+ *
+ * @alg:	algorithm definition
+ */
+void crypto_unregister_acomp(struct acomp_alg *alg);
+
+int crypto_register_acomps(struct acomp_alg *algs, int count);
+void crypto_unregister_acomps(struct acomp_alg *algs, int count);
+
+static inline bool acomp_request_issg(struct acomp_req *req)
+{
+	return !(req->base.flags & (CRYPTO_ACOMP_REQ_SRC_VIRT |
+				    CRYPTO_ACOMP_REQ_DST_VIRT));
+}
+
+static inline bool acomp_request_src_isvirt(struct acomp_req *req)
+{
+	return req->base.flags & CRYPTO_ACOMP_REQ_SRC_VIRT;
+}
+
+static inline bool acomp_request_dst_isvirt(struct acomp_req *req)
+{
+	return req->base.flags & CRYPTO_ACOMP_REQ_DST_VIRT;
+}
+
+static inline bool acomp_request_isvirt(struct acomp_req *req)
+{
+	return req->base.flags & (CRYPTO_ACOMP_REQ_SRC_VIRT |
+				  CRYPTO_ACOMP_REQ_DST_VIRT);
+}
+
+static inline bool acomp_request_src_isnondma(struct acomp_req *req)
+{
+	return req->base.flags & CRYPTO_ACOMP_REQ_SRC_NONDMA;
+}
+
+static inline bool acomp_request_dst_isnondma(struct acomp_req *req)
+{
+	return req->base.flags & CRYPTO_ACOMP_REQ_DST_NONDMA;
+}
+
+static inline bool acomp_request_isnondma(struct acomp_req *req)
+{
+	return req->base.flags & (CRYPTO_ACOMP_REQ_SRC_NONDMA |
+				  CRYPTO_ACOMP_REQ_DST_NONDMA);
+}
+
+static inline bool crypto_acomp_req_virt(struct crypto_acomp *tfm)
+{
+	return crypto_tfm_req_virt(&tfm->base);
+}
+
+void crypto_acomp_free_streams(struct crypto_acomp_streams *s);
+int crypto_acomp_alloc_streams(struct crypto_acomp_streams *s);
+
+#define crypto_acomp_lock_stream_bh(...) __acquire_ret(_crypto_acomp_lock_stream_bh(__VA_ARGS__), &__ret->lock);
+struct crypto_acomp_stream *_crypto_acomp_lock_stream_bh(
+		struct crypto_acomp_streams *s) __acquires_ret;
+
+static inline void crypto_acomp_unlock_stream_bh(
+	struct crypto_acomp_stream *stream) __releases(&stream->lock)
+{
+	spin_unlock_bh(&stream->lock);
+}
+
+void acomp_walk_done_src(struct acomp_walk *walk, int used);
+void acomp_walk_done_dst(struct acomp_walk *walk, int used);
+int acomp_walk_next_src(struct acomp_walk *walk);
+int acomp_walk_next_dst(struct acomp_walk *walk);
+int acomp_walk_virt(struct acomp_walk *__restrict walk,
+		    struct acomp_req *__restrict req, bool atomic);
+
+static inline bool acomp_walk_more_src(const struct acomp_walk *walk, int cur)
+{
+	return walk->slen != cur;
+}
+
+static inline u32 acomp_request_flags(struct acomp_req *req)
+{
+	return crypto_request_flags(&req->base) & ~CRYPTO_ACOMP_REQ_PRIVATE;
+}
+
+static inline struct crypto_acomp *crypto_acomp_fb(struct crypto_acomp *tfm)
+{
+	return __crypto_acomp_tfm(crypto_acomp_tfm(tfm)->fb);
+}
+
+static inline struct acomp_req *acomp_fbreq_on_stack_init(
+	char *buf, struct acomp_req *old)
+{
+	struct crypto_acomp *tfm = crypto_acomp_reqtfm(old);
+	struct acomp_req *req = (void *)buf;
+
+	crypto_stack_request_init(&req->base,
+				  crypto_acomp_tfm(crypto_acomp_fb(tfm)));
+	acomp_request_set_callback(req, acomp_request_flags(old), NULL, NULL);
+	req->base.flags &= ~CRYPTO_ACOMP_REQ_PRIVATE;
+	req->base.flags |= old->base.flags & CRYPTO_ACOMP_REQ_PRIVATE;
+	req->src = old->src;
+	req->dst = old->dst;
+	req->slen = old->slen;
+	req->dlen = old->dlen;
+
+	return req;
+}
+
+#endif