Commit-ID: d4d3ccc6d1eb74bd315d49a3829c5ad6c48d21b0
Gitweb: http://git.kernel.org/tip/d4d3ccc6d1eb74bd315d49a3829c5ad6c48d21b0
Author: Oleg Nesterov <oleg@xxxxxxxxxx>
AuthorDate: Sat, 24 Nov 2012 18:51:34 +0100
Committer: Oleg Nesterov <oleg@xxxxxxxxxx>
CommitDate: Fri, 8 Feb 2013 17:47:08 +0100
uprobes: Kill uprobe->copy_mutex
Now that ->register_rwsem is safe under ->mmap_sem we can kill
->copy_mutex and abuse down_write(&uprobe->consumer_rwsem).
This makes prepare_uprobe() even more ugly, but we should kill
it anyway.
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Acked-by: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>
---
kernel/events/uprobes.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 7ec2eb2..40ced98 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -91,7 +91,6 @@ struct uprobe {
atomic_t ref;
struct rw_semaphore register_rwsem;
struct rw_semaphore consumer_rwsem;
- struct mutex copy_mutex; /* TODO: kill me and UPROBE_COPY_INSN */
struct list_head pending_list;
struct uprobe_consumer *consumers;
struct inode *inode; /* Also hold a ref to inode */
@@ -450,7 +449,6 @@ static struct uprobe *alloc_uprobe(struct inode *inode, loff_t offset)
uprobe->offset = offset;
init_rwsem(&uprobe->register_rwsem);
init_rwsem(&uprobe->consumer_rwsem);
- mutex_init(&uprobe->copy_mutex);
/* For now assume that the instruction need not be single-stepped */
__set_bit(UPROBE_SKIP_SSTEP, &uprobe->flags);
@@ -578,7 +576,8 @@ static int prepare_uprobe(struct uprobe *uprobe, struct file *file,
if (test_bit(UPROBE_COPY_INSN, &uprobe->flags))
return ret;
- mutex_lock(&uprobe->copy_mutex);
+ /* TODO: move this into _register, until then we abuse this sem. */
+ down_write(&uprobe->consumer_rwsem);
if (test_bit(UPROBE_COPY_INSN, &uprobe->flags))
goto out;
@@ -602,7 +601,7 @@ static int prepare_uprobe(struct uprobe *uprobe, struct file *file,
set_bit(UPROBE_COPY_INSN, &uprobe->flags);
out:
- mutex_unlock(&uprobe->copy_mutex);
+ up_write(&uprobe->consumer_rwsem);
return ret;
}
--
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