summaryrefslogtreecommitdiff
path: root/include/linux/kexec.h
diff options
context:
space:
mode:
authorValentin Schneider <vschneid@redhat.com>2022-07-01 01:32:57 +0300
committerAndrew Morton <akpm@linux-foundation.org>2022-09-12 07:55:06 +0300
commit7bb5da0d490b2d836c5218f5186ee588d2145310 (patch)
tree2b6b1003e79581a22fa0438c40d48e42a645806a /include/linux/kexec.h
parent9847f21225c4eb0b843cb2b72ed83b32edb1e6f2 (diff)
downloadlinux-7bb5da0d490b2d836c5218f5186ee588d2145310.tar.xz
kexec: turn all kexec_mutex acquisitions into trylocks
Patch series "kexec, panic: Making crash_kexec() NMI safe", v4. This patch (of 2): Most acquistions of kexec_mutex are done via mutex_trylock() - those were a direct "translation" from: 8c5a1cf0ad3a ("kexec: use a mutex for locking rather than xchg()") there have however been two additions since then that use mutex_lock(): crash_get_memory_size() and crash_shrink_memory(). A later commit will replace said mutex with an atomic variable, and locking operations will become atomic_cmpxchg(). Rather than having those mutex_lock() become while (atomic_cmpxchg(&lock, 0, 1)), turn them into trylocks that can return -EBUSY on acquisition failure. This does halve the printable size of the crash kernel, but that's still neighbouring 2G for 32bit kernels which should be ample enough. Link: https://lkml.kernel.org/r/20220630223258.4144112-1-vschneid@redhat.com Link: https://lkml.kernel.org/r/20220630223258.4144112-2-vschneid@redhat.com Signed-off-by: Valentin Schneider <vschneid@redhat.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: "Eric W . Biederman" <ebiederm@xmission.com> Cc: Juri Lelli <jlelli@redhat.com> Cc: Luis Claudio R. Goncalves <lgoncalv@redhat.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Petr Mladek <pmladek@suse.com> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Baoquan He <bhe@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'include/linux/kexec.h')
-rw-r--r--include/linux/kexec.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index 13e6c4b58f07..41a686996aaa 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -427,7 +427,7 @@ extern int kexec_load_disabled;
extern bool kexec_in_progress;
int crash_shrink_memory(unsigned long new_size);
-size_t crash_get_memory_size(void);
+ssize_t crash_get_memory_size(void);
#ifndef arch_kexec_protect_crashkres
/*