Re: [PATCH V3] mm: convert rcu_read_lock() to srcu_read_lock(), thus allowing to sleep in callbacks
From: Andrea Arcangeli <hidden>
Date: 2012-03-21 18:02:30
Hi Sagi, There are a couple of rcu_read_lock not converted at the top. On Wed, Feb 08, 2012 at 03:55:43PM +0200, Sagi Grimberg wrote:
quoted hunk ↗ jump to hunk
@@ -196,6 +200,9 @@ static int do_mmu_notifier_register(struct mmu_notifier *mn, if (unlikely(!mmu_notifier_mm)) goto out; + if (init_srcu_struct(&mmu_notifier_mm->srcu)) + goto out_cleanup; + if (take_mmap_sem) down_write(&mm->mmap_sem);
out_cleanup will up_write if take_mmap_sem is set, and at that point the mmap_sem hasn't been taken yet.
quoted hunk ↗ jump to hunk
ret = mm_take_all_locks(mm);@@ -226,8 +233,11 @@ static int do_mmu_notifier_register(struct mmu_notifier *mn, out_cleanup: if (take_mmap_sem) up_write(&mm->mmap_sem); - /* kfree() does nothing if mmu_notifier_mm is NULL */ - kfree(mmu_notifier_mm); + + if (mm->mmu_notifier_mm) {
I guess this should be "if (mmu_notifier_mm)"; I happened to notice my older patch still applies cleanly and it has the above issues already correct, so I'm appending it after refreshing it to upstream. ====