linux-kernel - [PATCH v4 1/3] x86/sgx: Use sgx_free_epc_page() in sgx_reclaim

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Message-Id: <20210313160119.1318533-2-jarkko@kernel.org>
Date:   Sat, 13 Mar 2021 18:01:17 +0200
From:   Jarkko Sakkinen <jarkko@...nel.org>
To:     linux-sgx@...r.kernel.org
Cc:     Jarkko Sakkinen <jarkko@...nel.org>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        x86@...nel.org, "H. Peter Anvin" <hpa@...or.com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH v4 1/3] x86/sgx: Use sgx_free_epc_page() in sgx_reclaim_pages()

Replace the ad-hoc code with a sgx_free_epc_page(), in order to make sure
that all the relevant checks and book keeping is done, while freeing a
borrowed EPC page, and remove redundant code. EREMOVE inside
sgx_free_epc_page() does not change the semantics, as EREMOVE to an
uninitialize pages is a nop.

Signed-off-by: Jarkko Sakkinen <jarkko@...nel.org>
---

v4:
* Rewrote the commit message.

 arch/x86/kernel/cpu/sgx/main.c | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
index 8df81a3ed945..65004fb8a91f 100644
--- a/arch/x86/kernel/cpu/sgx/main.c
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -305,7 +305,6 @@ static void sgx_reclaim_pages(void)
 {
 	struct sgx_epc_page *chunk[SGX_NR_TO_SCAN];
 	struct sgx_backing backing[SGX_NR_TO_SCAN];
-	struct sgx_epc_section *section;
 	struct sgx_encl_page *encl_page;
 	struct sgx_epc_page *epc_page;
 	pgoff_t page_index;
@@ -378,11 +377,7 @@ static void sgx_reclaim_pages(void)
 		kref_put(&encl_page->encl->refcount, sgx_encl_release);
 		epc_page->flags &= ~SGX_EPC_PAGE_RECLAIMER_TRACKED;
 
-		section = &sgx_epc_sections[epc_page->section];
-		spin_lock(&section->lock);
-		list_add_tail(&epc_page->list, &section->page_list);
-		section->free_cnt++;
-		spin_unlock(&section->lock);
+		sgx_free_epc_page(epc_page);
 	}
 }
 
-- 
2.30.2