kevin/linux
1
Fork 0
Code

fs: add i_state helpers

Browse Source 
The i_state member is an unsigned long so that it can be used with the
wait bit infrastructure which expects unsigned long. This wastes 4 bytes
which we're unlikely to ever use. Switch to using the var event wait
mechanism using the address of the bit. Thanks to Linus for the address
idea.

Link: https://lore.kernel.org/r/20240823-work-i_state-v3-1-5cd5fd207a57@kernel.org
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Christian Brauner 2024-08-23 14:47:35 +02:00
parent 88b1afbf0f
commit da18ecbf0f
2 changed files with 26 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
fs/inode.c
View File

@ -472,6 +472,17 @@ static void __inode_add_lru(struct inode *inode, bool rotate)
inode->i_state |= I_REFERENCED;
}
struct wait_queue_head *inode_bit_waitqueue(struct wait_bit_queue_entry *wqe,
struct inode *inode, u32 bit)
{
void *bit_address;
bit_address = inode_state_wait_address(inode, bit);
init_wait_var_entry(wqe, bit_address, 0);
return __var_waitqueue(bit_address);
}
EXPORT_SYMBOL(inode_bit_waitqueue);
/*
* Add inode to LRU if needed (inode is unused and clean).
*

15
include/linux/fs.h
View File

@ -744,6 +744,21 @@ struct inode {
void *i_private; /* fs or device private pointer */
} __randomize_layout;
/*
* Get bit address from inode->i_state to use with wait_var_event()
* infrastructre.
*/
#define inode_state_wait_address(inode, bit) ((char *)&(inode)->i_state + (bit))
struct wait_queue_head *inode_bit_waitqueue(struct wait_bit_queue_entry *wqe,
struct inode *inode, u32 bit);
static inline void inode_wake_up_bit(struct inode *inode, u32 bit)
{
/* Caller is responsible for correct memory barriers. */
wake_up_var(inode_state_wait_address(inode, bit));
}
struct timespec64 timestamp_truncate(struct timespec64 t, struct inode *inode);
static inline unsigned int i_blocksize(const struct inode *node)