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Message-Id: <12f4b3dc5254547d12cb6669c45c533e647511fb.1532563124.git.osandov@fb.com>
Date: Wed, 25 Jul 2018 16:59:12 -0700
From: Omar Sandoval <osandov@...ndov.com>
To: linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
Andrew Morton <akpm@...ux-foundation.org>
Cc: Alexey Dobriyan <adobriyan@...il.com>,
Eric Biederman <ebiederm@...ssion.com>,
James Morse <james.morse@....com>,
Bhupesh Sharma <bhsharma@...hat.com>, kernel-team@...com
Subject: [PATCH v4 1/9] proc/kcore: don't grab lock for kclist_add()
From: Omar Sandoval <osandov@...com>
kclist_add() is only called at init time, so there's no point in
grabbing any locks. We're also going to replace the rwlock with a rwsem,
which we don't want to try grabbing during early boot.
While we're here, mark kclist_add() with __init so that we'll get a
warning if it's called from non-init code.
Reviewed-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Omar Sandoval <osandov@...com>
---
fs/proc/kcore.c | 7 +++----
include/linux/kcore.h | 2 +-
2 files changed, 4 insertions(+), 5 deletions(-)
diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c
index 66c373230e60..b0b9a76f28d6 100644
--- a/fs/proc/kcore.c
+++ b/fs/proc/kcore.c
@@ -62,16 +62,15 @@ static LIST_HEAD(kclist_head);
static DEFINE_RWLOCK(kclist_lock);
static int kcore_need_update = 1;
-void
-kclist_add(struct kcore_list *new, void *addr, size_t size, int type)
+/* This doesn't grab kclist_lock, so it should only be used at init time. */
+void __init kclist_add(struct kcore_list *new, void *addr, size_t size,
+ int type)
{
new->addr = (unsigned long)addr;
new->size = size;
new->type = type;
- write_lock(&kclist_lock);
list_add_tail(&new->list, &kclist_head);
- write_unlock(&kclist_lock);
}
static size_t get_kcore_size(int *nphdr, size_t *elf_buflen)
diff --git a/include/linux/kcore.h b/include/linux/kcore.h
index 8de55e4b5ee9..c20f296438fb 100644
--- a/include/linux/kcore.h
+++ b/include/linux/kcore.h
@@ -35,7 +35,7 @@ struct vmcoredd_node {
};
#ifdef CONFIG_PROC_KCORE
-extern void kclist_add(struct kcore_list *, void *, size_t, int type);
+void __init kclist_add(struct kcore_list *, void *, size_t, int type);
#else
static inline
void kclist_add(struct kcore_list *new, void *addr, size_t size, int type)
--
2.18.0
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