unimore/kernel-hacking-2024-linux-steffo
unimore/kernel-hacking-2024-linux-steffo
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inode: remove __I_DIO_WAKEUP

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Afaict, we can just rely on inode->i_dio_count for waiting instead of
this awkward indirection through __I_DIO_WAKEUP. This survives LTP dio
and xfstests dio tests.

Link: https://lore.kernel.org/r/20240816-vfs-misc-dio-v1-1-80fe21a2c710@kernel.org
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Christian Brauner 2024-08-16 16:35:52 +02:00
parent 3717bbcb59
commit 1c48d44146
3 changed files with 19 additions and 34 deletions
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23
fs/inode.c
View file

@ -2500,18 +2500,11 @@ EXPORT_SYMBOL(inode_owner_or_capable);
/*
* Direct i/o helper functions
*/
static void __inode_dio_wait(struct inode *inode)
bool inode_dio_finished(const struct inode *inode)
{
wait_queue_head_t *wq = bit_waitqueue(&inode->i_state, __I_DIO_WAKEUP);
DEFINE_WAIT_BIT(q, &inode->i_state, __I_DIO_WAKEUP);
do {
prepare_to_wait(wq, &q.wq_entry, TASK_UNINTERRUPTIBLE);
if (atomic_read(&inode->i_dio_count))
schedule();
} while (atomic_read(&inode->i_dio_count));
finish_wait(wq, &q.wq_entry);
return atomic_read(&inode->i_dio_count) == 0;
}
EXPORT_SYMBOL(inode_dio_finished);
/**
* inode_dio_wait - wait for outstanding DIO requests to finish
@ -2525,11 +2518,17 @@ static void __inode_dio_wait(struct inode *inode)
*/
void inode_dio_wait(struct inode *inode)
{
if (atomic_read(&inode->i_dio_count))
__inode_dio_wait(inode);
wait_var_event(&inode->i_dio_count, inode_dio_finished(inode));
}
EXPORT_SYMBOL(inode_dio_wait);
void inode_dio_wait_interruptible(struct inode *inode)
{
wait_var_event_interruptible(&inode->i_dio_count,
inode_dio_finished(inode));
}
EXPORT_SYMBOL(inode_dio_wait_interruptible);
/*
* inode_set_flags - atomically set some inode flags
*

22
fs/netfs/locking.c
View file

@ -19,25 +19,13 @@
* Must be called under a lock that serializes taking new references
* to i_dio_count, usually by inode->i_mutex.
*/
static int inode_dio_wait_interruptible(struct inode *inode)
static int netfs_inode_dio_wait_interruptible(struct inode *inode)
{
if (!atomic_read(&inode->i_dio_count))
if (inode_dio_finished(inode))
return 0;
wait_queue_head_t *wq = bit_waitqueue(&inode->i_state, __I_DIO_WAKEUP);
DEFINE_WAIT_BIT(q, &inode->i_state, __I_DIO_WAKEUP);
for (;;) {
prepare_to_wait(wq, &q.wq_entry, TASK_INTERRUPTIBLE);
if (!atomic_read(&inode->i_dio_count))
break;
if (signal_pending(current))
break;
schedule();
}
finish_wait(wq, &q.wq_entry);
return atomic_read(&inode->i_dio_count) ? -ERESTARTSYS : 0;
inode_dio_wait_interruptible(inode);
return !inode_dio_finished(inode) ? -ERESTARTSYS : 0;
}
/* Call with exclusively locked inode->i_rwsem */
@ -46,7 +34,7 @@ static int netfs_block_o_direct(struct netfs_inode *ictx)
if (!test_bit(NETFS_ICTX_ODIRECT, &ictx->flags))
return 0;
clear_bit(NETFS_ICTX_ODIRECT, &ictx->flags);
return inode_dio_wait_interruptible(&ictx->inode);
return netfs_inode_dio_wait_interruptible(&ictx->inode);
}
/**

8
include/linux/fs.h
View file

@ -2373,8 +2373,6 @@ static inline void kiocb_clone(struct kiocb *kiocb, struct kiocb *kiocb_src,
*
* I_REFERENCED Marks the inode as recently references on the LRU list.
*
* I_DIO_WAKEUP Never set. Only used as a key for wait_on_bit().
*
* I_WB_SWITCH Cgroup bdi_writeback switching in progress. Used to
* synchronize competing switching instances and to tell
* wb stat updates to grab the i_pages lock. See
@ -2409,8 +2407,6 @@ static inline void kiocb_clone(struct kiocb *kiocb, struct kiocb *kiocb_src,
#define __I_SYNC 7
#define I_SYNC (1 << __I_SYNC)
#define I_REFERENCED (1 << 8)
#define __I_DIO_WAKEUP 9
#define I_DIO_WAKEUP (1 << __I_DIO_WAKEUP)
#define I_LINKABLE (1 << 10)
#define I_DIRTY_TIME (1 << 11)
#define I_WB_SWITCH (1 << 13)
@ -3227,7 +3223,9 @@ static inline ssize_t blockdev_direct_IO(struct kiocb *iocb,
}
#endif
bool inode_dio_finished(const struct inode *inode);
void inode_dio_wait(struct inode *inode);
void inode_dio_wait_interruptible(struct inode *inode);
/**
* inode_dio_begin - signal start of a direct I/O requests
@ -3251,7 +3249,7 @@ static inline void inode_dio_begin(struct inode *inode)
static inline void inode_dio_end(struct inode *inode)
{
if (atomic_dec_and_test(&inode->i_dio_count))
wake_up_bit(&inode->i_state, __I_DIO_WAKEUP);
wake_up_var(&inode->i_dio_count);
}
extern void inode_set_flags(struct inode *inode, unsigned int flags,