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d8753f788a
Open-coded accesses prevent asserting they are done correctly. One obvious aspect is locking, but significantly more can checked. For example it can be detected when the code is clearing flags which are already missing, or is setting flags when it is illegal (e.g., I_FREEING when ->i_count > 0). In order to keep things manageable this patchset merely gets the thing off the ground with only lockdep checks baked in. Current consumers can be trivially converted. Suppose flags I_A and I_B are to be handled. If ->i_lock is held, then: state = inode->i_state => state = inode_state_read(inode) inode->i_state |= (I_A | I_B) => inode_state_set(inode, I_A | I_B) inode->i_state &= ~(I_A | I_B) => inode_state_clear(inode, I_A | I_B) inode->i_state = I_A | I_B => inode_state_assign(inode, I_A | I_B) If ->i_lock is not held or only held conditionally: state = inode->i_state => state = inode_state_read_once(inode) inode->i_state |= (I_A | I_B) => inode_state_set_raw(inode, I_A | I_B) inode->i_state &= ~(I_A | I_B) => inode_state_clear_raw(inode, I_A | I_B) inode->i_state = I_A | I_B => inode_state_assign_raw(inode, I_A | I_B) The "_once" vs "_raw" discrepancy stems from the read variant differing by READ_ONCE as opposed to just lockdep checks. Finally, if you want to atomically clear flags and set new ones, the following: state = inode->i_state; state &= ~I_A; state |= I_B; inode->i_state = state; turns into: inode_state_replace(inode, I_A, I_B); Signed-off-by: Mateusz Guzik <mjguzik@gmail.com> Signed-off-by: Christian Brauner <brauner@kernel.org> |
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