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authorMatias Bjørling <m@bjorling.me>2016-07-07 09:54:17 +0200
committerJens Axboe <axboe@fb.com>2016-07-07 08:51:52 -0600
commit5cd907853d5b777c11ecbc8de4482ea5f51663bc (patch)
tree23cf4e800cba9be0351780bb82824713ade3dc82
parentb76eb20bb0c6f4f9c2e1ad493f73c52817b8aaff (diff)
downloadlinux-5cd907853d5b777c11ecbc8de4482ea5f51663bc.tar.bz2
lightnvm: remove nested lock conflict with mm
If a media manager tries to initialize it targets upon media manager initialization, the media manager will need to know which target types are available in LightNVM. The lists of which managers and target types are available shares the same lock. Therefore, on initialization, the nvm_lock is taken by LightNVM core, which later leads to a deadlock when target types are enumerated by the media manager. Add an exclusive lock for target types to resolve this conflict. Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@fb.com>
-rw-r--r--drivers/lightnvm/core.c9
1 files changed, 5 insertions, 4 deletions
diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
index 8afb04cc4d5a..04469e0c84ce 100644
--- a/drivers/lightnvm/core.c
+++ b/drivers/lightnvm/core.c
@@ -28,6 +28,7 @@
#include <linux/sched/sysctl.h>
static LIST_HEAD(nvm_tgt_types);
+static DECLARE_RWSEM(nvm_tgtt_lock);
static LIST_HEAD(nvm_mgrs);
static LIST_HEAD(nvm_devices);
static DECLARE_RWSEM(nvm_lock);
@@ -37,7 +38,7 @@ struct nvm_tgt_type *nvm_find_target_type(const char *name, int lock)
struct nvm_tgt_type *tmp, *tt = NULL;
if (lock)
- down_write(&nvm_lock);
+ down_write(&nvm_tgtt_lock);
list_for_each_entry(tmp, &nvm_tgt_types, list)
if (!strcmp(name, tmp->name)) {
@@ -46,7 +47,7 @@ struct nvm_tgt_type *nvm_find_target_type(const char *name, int lock)
}
if (lock)
- up_write(&nvm_lock);
+ up_write(&nvm_tgtt_lock);
return tt;
}
EXPORT_SYMBOL(nvm_find_target_type);
@@ -55,12 +56,12 @@ int nvm_register_tgt_type(struct nvm_tgt_type *tt)
{
int ret = 0;
- down_write(&nvm_lock);
+ down_write(&nvm_tgtt_lock);
if (nvm_find_target_type(tt->name, 0))
ret = -EEXIST;
else
list_add(&tt->list, &nvm_tgt_types);
- up_write(&nvm_lock);
+ up_write(&nvm_tgtt_lock);
return ret;
}