linux-kernel - [PATCH v2 1/2] tee: amdtee: use page_alloc

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Date:   Wed, 30 Aug 2023 01:49:42 +0530
From:   Devaraj Rangasamy <Devaraj.Rangasamy@....com>
To:     Jonathan Corbet <corbet@....net>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Dave Hansen <dave.hansen@...ux.intel.com>, <x86@...nel.org>,
        "H . Peter Anvin" <hpa@...or.com>,
        Jens Wiklander <jens.wiklander@...aro.org>,
        Sumit Garg <sumit.garg@...aro.org>,
        "Paul E . McKenney" <paulmck@...nel.org>,
        "Catalin Marinas" <catalin.marinas@....com>,
        Randy Dunlap <rdunlap@...radead.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Steven Rostedt <rostedt@...dmis.org>,
        Daniel Sneddon <daniel.sneddon@...ux.intel.com>,
        Rijo Thomas <Rijo-john.Thomas@....com>,
        Devaraj Rangasamy <Devaraj.Rangasamy@....com>,
        SivaSangeetha SK <SivaSangeetha.SK@....com>,
        Josh Poimboeuf <jpoimboe@...nel.org>,
        Juergen Gross <jgross@...e.com>,
        Ard Biesheuvel <ardb@...nel.org>,
        Ross Lagerwall <ross.lagerwall@...rix.com>,
        Yuntao Wang <ytcoode@...il.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Jarkko Nikula <jarkko.nikula@...ux.intel.com>,
        Herbert Xu <herbert@...dor.apana.org.au>,
        Tom Lendacky <thomas.lendacky@....com>,
        Mario Limonciello <mario.limonciello@....com>,
        <linux-doc@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <op-tee@...ts.trustedfirmware.org>
CC:     Mythri PK <Mythri.Pandeshwarakrishna@....com>,
        Nimesh Easow <Nimesh.Easow@....com>
Subject: [PATCH v2 1/2] tee: amdtee: use page_alloc_exact() for memory allocations

Use page_alloc_exact() to get buffers, instead of
get_free_pages(), so as to avoid wastage of memory.
Currently get_free_pages() is allocating at next order,
while page_alloc_exact() will free the unused pages.

Signed-off-by: Devaraj Rangasamy <Devaraj.Rangasamy@....com>
---
 v2:
 * Replaced __get_free_pages() with alloc_pages_exact().

 drivers/tee/amdtee/shm_pool.c | 18 ++++++++----------
 1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/drivers/tee/amdtee/shm_pool.c b/drivers/tee/amdtee/shm_pool.c
index f0303126f199..156e8a6f631f 100644
--- a/drivers/tee/amdtee/shm_pool.c
+++ b/drivers/tee/amdtee/shm_pool.c
@@ -4,6 +4,7 @@
  */
 
 #include <linux/slab.h>
+#include <linux/mm.h>
 #include <linux/tee_drv.h>
 #include <linux/psp.h>
 #include "amdtee_private.h"
@@ -11,26 +12,23 @@
 static int pool_op_alloc(struct tee_shm_pool *pool, struct tee_shm *shm,
 			 size_t size, size_t align)
 {
-	unsigned int order = get_order(size);
-	unsigned long va;
+	void *va;
 	int rc;
 
-	/*
-	 * Ignore alignment since this is already going to be page aligned
-	 * and there's no need for any larger alignment.
-	 */
-	va = __get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
+	size = PAGE_ALIGN(size);
+
+	va = alloc_pages_exact(size, GFP_KERNEL | __GFP_ZERO);
 	if (!va)
 		return -ENOMEM;
 
 	shm->kaddr = (void *)va;
 	shm->paddr = __psp_pa((void *)va);
-	shm->size = PAGE_SIZE << order;
+	shm->size = size;
 
 	/* Map the allocated memory in to TEE */
 	rc = amdtee_map_shmem(shm);
 	if (rc) {
-		free_pages(va, order);
+		free_pages_exact(va, size);
 		shm->kaddr = NULL;
 		return rc;
 	}
@@ -42,7 +40,7 @@ static void pool_op_free(struct tee_shm_pool *pool, struct tee_shm *shm)
 {
 	/* Unmap the shared memory from TEE */
 	amdtee_unmap_shmem(shm);
-	free_pages((unsigned long)shm->kaddr, get_order(shm->size));
+	free_pages_exact(shm->kaddr, shm->size);
 	shm->kaddr = NULL;
 }
 
-- 
2.25.1