[PATCH v3 03/14] fs: aio: Remove redundant rcu_read_lock/unlock() in spin_lock
From: pengdonglin <hidden>
Date: 2025-09-16 04:48:34
Also in:
cgroups, intel-gfx, linux-acpi, linux-fsdevel, linux-nfs, linux-rt-devel, linux-s390, linux-security-module, linux-wireless, lkml
Subsystem:
aio, filesystems (vfs and infrastructure), the rest · Maintainers:
Benjamin LaHaise, Alexander Viro, Christian Brauner, Linus Torvalds
From: pengdonglin <redacted>
Since commit a8bb74acd8efe ("rcu: Consolidate RCU-sched update-side function definitions")
there is no difference between rcu_read_lock(), rcu_read_lock_bh() and
rcu_read_lock_sched() in terms of RCU read section and the relevant grace
period. That means that spin_lock(), which implies rcu_read_lock_sched(),
also implies rcu_read_lock().
There is no need no explicitly start a RCU read section if one has already
been started implicitly by spin_lock().
Simplify the code and remove the inner rcu_read_lock() invocation.
Cc: Benjamin LaHaise <bcrl@kvack.org>
Signed-off-by: pengdonglin <redacted>
Signed-off-by: pengdonglin <redacted>
---
fs/aio.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/fs/aio.c b/fs/aio.c
index 7fc7b6221312..e3f9a5a391b5 100644
--- a/fs/aio.c
+++ b/fs/aio.c@@ -359,15 +359,14 @@ static int aio_ring_mremap(struct vm_area_struct *vma) int i, res = -EINVAL; spin_lock(&mm->ioctx_lock); - rcu_read_lock(); - table = rcu_dereference(mm->ioctx_table); + table = rcu_dereference_check(mm->ioctx_table, lockdep_is_held(&mm->ioctx_lock)); if (!table) goto out_unlock; for (i = 0; i < table->nr; i++) { struct kioctx *ctx; - ctx = rcu_dereference(table->table[i]); + ctx = rcu_dereference_check(table->table[i], lockdep_is_held(&mm->ioctx_lock)); if (ctx && ctx->aio_ring_file == file) { if (!atomic_read(&ctx->dead)) { ctx->user_id = ctx->mmap_base = vma->vm_start;
@@ -378,7 +377,6 @@ static int aio_ring_mremap(struct vm_area_struct *vma) } out_unlock: - rcu_read_unlock(); spin_unlock(&mm->ioctx_lock); return res; }
--
2.34.1