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uprobes: Kill uprobe->copy_mutex

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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@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
This commit is contained in:
Oleg Nesterov 2012-11-24 18:51:34 +01:00
parent bb929284be
commit d4d3ccc6d1
1 changed files with 3 additions and 4 deletions
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7
kernel/events/uprobes.c
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@ -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;
}