linux-kernel - [tip: perf/core] perf/ring_buffer: Matching the memory allocate and free, in rb

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Date:   Fri, 18 Oct 2019 12:48:09 -0000
From:   "tip-bot2 for Yunfeng Ye" <tip-bot2@...utronix.de>
To:     linux-tip-commits@...r.kernel.org
Cc:     Yunfeng Ye <yeyunfeng@...wei.com>,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>, <jolsa@...hat.co>,
        <acme@...nel.org>, <mingo@...hat.com>, <mark.rutland@....com>,
        <namhyung@...nel.org>, <alexander.shishkin@...ux.intel.com>,
        Ingo Molnar <mingo@...nel.org>, Borislav Petkov <bp@...en8.de>,
        linux-kernel@...r.kernel.org
Subject: [tip: perf/core] perf/ring_buffer: Matching the memory allocate and
 free, in rb_alloc()

The following commit has been merged into the perf/core branch of tip:

Commit-ID:     d7e78706e43107fa269fe34b1a69e653f5ec9f2c
Gitweb:        https://git.kernel.org/tip/d7e78706e43107fa269fe34b1a69e653f5ec9f2c
Author:        Yunfeng Ye <yeyunfeng@...wei.com>
AuthorDate:    Mon, 14 Oct 2019 16:15:57 +08:00
Committer:     Peter Zijlstra <peterz@...radead.org>
CommitterDate: Thu, 17 Oct 2019 21:31:55 +02:00

perf/ring_buffer: Matching the memory allocate and free, in rb_alloc()

Currently perf_mmap_alloc_page() is used to allocate memory in
rb_alloc(), but using free_page() to free memory in the failure path.

It's better to use perf_mmap_free_page() instead.

Signed-off-by: Yunfeng Ye <yeyunfeng@...wei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Cc: <jolsa@...hat.co>
Cc: <acme@...nel.org>
Cc: <mingo@...hat.com>
Cc: <mark.rutland@....com>
Cc: <namhyung@...nel.org>
Cc: <alexander.shishkin@...ux.intel.com>
Link: https://lkml.kernel.org/r/575c7e8c-90c7-4e3a-b41d-f894d8cdbd7f@huawei.com
---
 kernel/events/ring_buffer.c | 20 ++++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
index abc145c..246c83a 100644
--- a/kernel/events/ring_buffer.c
+++ b/kernel/events/ring_buffer.c
@@ -754,6 +754,14 @@ static void *perf_mmap_alloc_page(int cpu)
 	return page_address(page);
 }
 
+static void perf_mmap_free_page(void *addr)
+{
+	struct page *page = virt_to_page(addr);
+
+	page->mapping = NULL;
+	__free_page(page);
+}
+
 struct ring_buffer *rb_alloc(int nr_pages, long watermark, int cpu, int flags)
 {
 	struct ring_buffer *rb;
@@ -788,9 +796,9 @@ struct ring_buffer *rb_alloc(int nr_pages, long watermark, int cpu, int flags)
 
 fail_data_pages:
 	for (i--; i >= 0; i--)
-		free_page((unsigned long)rb->data_pages[i]);
+		perf_mmap_free_page(rb->data_pages[i]);
 
-	free_page((unsigned long)rb->user_page);
+	perf_mmap_free_page(rb->user_page);
 
 fail_user_page:
 	kfree(rb);
@@ -799,14 +807,6 @@ fail:
 	return NULL;
 }
 
-static void perf_mmap_free_page(void *addr)
-{
-	struct page *page = virt_to_page(addr);
-
-	page->mapping = NULL;
-	__free_page(page);
-}
-
 void rb_free(struct ring_buffer *rb)
 {
 	int i;