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| author | Kees Cook <kees+treewide@kernel.org> | 2026-09-02 15:31:14 -0700 |
|---|---|---|
| committer | Kees Cook <kees@kernel.org> | 2026-09-04 21:37:00 -0700 |
| commit | 3a2c4d55e32ad65efebdb6de44eef3bfa08bb49d (patch) | |
| tree | c65086f9bdcd48c6360fb7cb4598bca084da1f32 /fs/btrfs/locking.h | |
| download | linux-stable-3a2c4d55e32ad65efebdb6de44eef3bfa08bb49d.tar.gz linux-stable-3a2c4d55e32ad65efebdb6de44eef3bfa08bb49d.zip | |
treewide: refresh kmalloc_obj() conversionsgrafted
This is another run of the Coccinelle script for converting kmalloc()
family of allocations to kmalloc_obj() via the existing rules in
scripts/coccinelle/api/kmalloc_objs.cocci
This catches both the set of kmalloc() uses added since the first
kmalloc_obj() conversions in v7.0 and adds a large group missed in the
first pass due to Coccinelle not interacting well with the cleanup.h
scoped_...() family of macros[1]. I worked around this with spatch's
"--macro-file" argument to a file with all the scoped_...() macros mapped
to Coccinelle's YACFE_ITERATOR[2] as that was the closest viable control
flow indicator I could find.
Build tested allmodconfig on x86, arm64, arm, loongarch, mips, powerpc,
riscv, and s390 with no new warnings.
Link: https://lore.kernel.org/lkml/202609021314.8A9C0B8@keescook/ [1]
Link: https://github.com/coccinelle/coccinelle/blob/master/standard.h [2]
Signed-off-by: Kees Cook <kees+treewide@kernel.org>
Diffstat (limited to 'fs/btrfs/locking.h')
| -rw-r--r-- | fs/btrfs/locking.h | 251 |
1 files changed, 251 insertions, 0 deletions
diff --git a/fs/btrfs/locking.h b/fs/btrfs/locking.h new file mode 100644 index 000000000..a4673e7d9 --- /dev/null +++ b/fs/btrfs/locking.h @@ -0,0 +1,251 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 2008 Oracle. All rights reserved. + */ + +#ifndef BTRFS_LOCKING_H +#define BTRFS_LOCKING_H + +#include <linux/atomic.h> +#include <linux/wait.h> +#include <linux/lockdep.h> +#include <linux/percpu_counter.h> +#include "extent_io.h" + +struct extent_buffer; +struct btrfs_path; +struct btrfs_root; + +#define BTRFS_WRITE_LOCK 1 +#define BTRFS_READ_LOCK 2 + +/* + * We are limited in number of subclasses by MAX_LOCKDEP_SUBCLASSES, which at + * the time of this patch is 8, which is how many we use. Keep this in mind if + * you decide you want to add another subclass. + */ +enum btrfs_lock_nesting { + BTRFS_NESTING_NORMAL, + + /* + * When we COW a block we are holding the lock on the original block, + * and since our lockdep maps are rootid+level, this confuses lockdep + * when we lock the newly allocated COW'd block. Handle this by having + * a subclass for COW'ed blocks so that lockdep doesn't complain. + */ + BTRFS_NESTING_COW, + + /* + * Oftentimes we need to lock adjacent nodes on the same level while + * still holding the lock on the original node we searched to, such as + * for searching forward or for split/balance. + * + * Because of this we need to indicate to lockdep that this is + * acceptable by having a different subclass for each of these + * operations. + */ + BTRFS_NESTING_LEFT, + BTRFS_NESTING_RIGHT, + + /* + * When splitting we will be holding a lock on the left/right node when + * we need to cow that node, thus we need a new set of subclasses for + * these two operations. + */ + BTRFS_NESTING_LEFT_COW, + BTRFS_NESTING_RIGHT_COW, + + /* + * When splitting we may push nodes to the left or right, but still use + * the subsequent nodes in our path, keeping our locks on those adjacent + * blocks. Thus when we go to allocate a new split block we've already + * used up all of our available subclasses, so this subclass exists to + * handle this case where we need to allocate a new split block. + */ + BTRFS_NESTING_SPLIT, + + /* + * When promoting a new block to a root we need to have a special + * subclass so we don't confuse lockdep, as it will appear that we are + * locking a higher level node before a lower level one. Copying also + * has this problem as it appears we're locking the same block again + * when we make a snapshot of an existing root. + */ + BTRFS_NESTING_NEW_ROOT, + + /* + * We are limited to MAX_LOCKDEP_SUBCLASSES number of subclasses, so + * add this in here and add a static_assert to keep us from going over + * the limit. As of this writing we're limited to 8, and we're + * definitely using 8, hence this check to keep us from messing up in + * the future. + */ + BTRFS_NESTING_MAX, +}; + +enum btrfs_lockdep_trans_states { + BTRFS_LOCKDEP_TRANS_COMMIT_PREP, + BTRFS_LOCKDEP_TRANS_UNBLOCKED, + BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED, + BTRFS_LOCKDEP_TRANS_COMPLETED, +}; + +/* + * Lockdep annotation for wait events. + * + * @owner: The struct where the lockdep map is defined + * @lock: The lockdep map corresponding to a wait event + * + * This macro is used to annotate a wait event. In this case a thread acquires + * the lockdep map as writer (exclusive lock) because it has to block until all + * the threads that hold the lock as readers signal the condition for the wait + * event and release their locks. + */ +#define btrfs_might_wait_for_event(owner, lock) \ + do { \ + rwsem_acquire(&owner->lock##_map, 0, 0, _THIS_IP_); \ + rwsem_release(&owner->lock##_map, _THIS_IP_); \ + } while (0) + +/* + * Protection for the resource/condition of a wait event. + * + * @owner: The struct where the lockdep map is defined + * @lock: The lockdep map corresponding to a wait event + * + * Many threads can modify the condition for the wait event at the same time + * and signal the threads that block on the wait event. The threads that modify + * the condition and do the signaling acquire the lock as readers (shared + * lock). + */ +#define btrfs_lockdep_acquire(owner, lock) \ + rwsem_acquire_read(&owner->lock##_map, 0, 0, _THIS_IP_) + +/* + * Used after signaling the condition for a wait event to release the lockdep + * map held by a reader thread. + */ +#define btrfs_lockdep_release(owner, lock) \ + rwsem_release(&owner->lock##_map, _THIS_IP_) + +/* + * Used to account for the fact that when doing io_uring encoded I/O, we can + * return to userspace with the inode lock still held. + */ +#define btrfs_lockdep_inode_acquire(owner, lock) \ + rwsem_acquire_read(&owner->vfs_inode.lock.dep_map, 0, 0, _THIS_IP_) + +#define btrfs_lockdep_inode_release(owner, lock) \ + rwsem_release(&owner->vfs_inode.lock.dep_map, _THIS_IP_) + +/* + * Macros for the transaction states wait events, similar to the generic wait + * event macros. + */ +#define btrfs_might_wait_for_state(owner, i) \ + do { \ + rwsem_acquire(&owner->btrfs_state_change_map[i], 0, 0, _THIS_IP_); \ + rwsem_release(&owner->btrfs_state_change_map[i], _THIS_IP_); \ + } while (0) + +#define btrfs_trans_state_lockdep_acquire(owner, i) \ + rwsem_acquire_read(&owner->btrfs_state_change_map[i], 0, 0, _THIS_IP_) + +#define btrfs_trans_state_lockdep_release(owner, i) \ + rwsem_release(&owner->btrfs_state_change_map[i], _THIS_IP_) + +/* Initialization of the lockdep map */ +#define btrfs_lockdep_init_map(owner, lock) \ + do { \ + static struct lock_class_key lock##_key; \ + lockdep_init_map(&owner->lock##_map, #lock, &lock##_key, 0); \ + } while (0) + +/* Initialization of the transaction states lockdep maps. */ +#define btrfs_state_lockdep_init_map(owner, lock, state) \ + do { \ + static struct lock_class_key lock##_key; \ + lockdep_init_map(&owner->btrfs_state_change_map[state], #lock, \ + &lock##_key, 0); \ + } while (0) + +static_assert(BTRFS_NESTING_MAX <= MAX_LOCKDEP_SUBCLASSES, + "too many lock subclasses defined"); + +void btrfs_tree_lock_nested(struct extent_buffer *eb, enum btrfs_lock_nesting nest); + +static inline void btrfs_tree_lock(struct extent_buffer *eb) +{ + btrfs_tree_lock_nested(eb, BTRFS_NESTING_NORMAL); +} + +void btrfs_tree_unlock(struct extent_buffer *eb); + +void btrfs_tree_read_lock_nested(struct extent_buffer *eb, enum btrfs_lock_nesting nest); + +static inline void btrfs_tree_read_lock(struct extent_buffer *eb) +{ + btrfs_tree_read_lock_nested(eb, BTRFS_NESTING_NORMAL); +} + +void btrfs_tree_read_unlock(struct extent_buffer *eb); +bool btrfs_try_tree_read_lock(struct extent_buffer *eb); +struct extent_buffer *btrfs_lock_root_node(struct btrfs_root *root); +struct extent_buffer *btrfs_read_lock_root_node(struct btrfs_root *root); +struct extent_buffer *btrfs_try_read_lock_root_node(struct btrfs_root *root); + +#ifdef CONFIG_BTRFS_DEBUG +static inline void btrfs_assert_tree_write_locked(struct extent_buffer *eb) +{ + lockdep_assert_held_write(&eb->lock); +} +static inline void btrfs_assert_tree_read_locked(struct extent_buffer *eb) +{ + lockdep_assert_held_read(&eb->lock); +} +#else +static inline void btrfs_assert_tree_write_locked(struct extent_buffer *eb) { } +static inline void btrfs_assert_tree_read_locked(struct extent_buffer *eb) { } +#endif + +void btrfs_unlock_up_safe(struct btrfs_path *path, int level); + +static inline void btrfs_tree_unlock_rw(struct extent_buffer *eb, int rw) +{ + if (rw == BTRFS_WRITE_LOCK) + btrfs_tree_unlock(eb); + else if (rw == BTRFS_READ_LOCK) + btrfs_tree_read_unlock(eb); + else + BUG(); +} + +struct btrfs_drew_lock { + atomic_t readers; + atomic_t writers; + wait_queue_head_t pending_writers; + wait_queue_head_t pending_readers; +}; + +void btrfs_drew_lock_init(struct btrfs_drew_lock *lock); +void btrfs_drew_write_lock(struct btrfs_drew_lock *lock); +bool btrfs_drew_try_write_lock(struct btrfs_drew_lock *lock); +void btrfs_drew_write_unlock(struct btrfs_drew_lock *lock); +void btrfs_drew_read_lock(struct btrfs_drew_lock *lock); +void btrfs_drew_read_unlock(struct btrfs_drew_lock *lock); + +#ifdef CONFIG_DEBUG_LOCK_ALLOC +void btrfs_set_buffer_lockdep_class(u64 objectid, struct extent_buffer *eb, int level); +void btrfs_maybe_reset_lockdep_class(struct btrfs_root *root, struct extent_buffer *eb); +#else +static inline void btrfs_set_buffer_lockdep_class(u64 objectid, + struct extent_buffer *eb, int level) +{ +} +static inline void btrfs_maybe_reset_lockdep_class(struct btrfs_root *root, + struct extent_buffer *eb) +{ +} +#endif + +#endif |
