[PATCH v3 2/6] ima: Remove inode lock

[Mimi Zohar]

On Wed, 2025-01-22 at 18:24 +0100, Roberto Sassu wrote:
> From: Roberto Sassu <roberto.sassu at huawei.com>
> 
> Move out the mutex in the ima_iint_cache structure to a new structure
> called ima_iint_cache_lock, so that a lock can be taken regardless of
> whether or not inode integrity metadata are stored in the inode.
> 
> Introduce ima_inode_security() to retrieve the ima_iint_cache_lock
> structure, if inode i_security is not NULL, and consequently remove
> ima_inode_get_iint() and ima_inode_set_iint(), since the ima_iint_cache
> structure can be read and modified from the new structure.
> 
> Move the mutex initialization and annotation in the new function
> ima_inode_alloc_security() and introduce ima_iint_lock() and
> ima_iint_unlock() to respectively lock and unlock the mutex.
> 
> Finally, expand the critical region in process_measurement() guarded by
> iint->mutex up to where the inode was locked, use only one iint lock in
> __ima_inode_hash(), since the mutex is now in the inode security blob, and
> replace the inode_lock()/inode_unlock() calls in ima_check_last_writer().
> 
> Signed-off-by: Roberto Sassu <roberto.sassu at huawei.com>
> Reviewed-by: Paul Moore <paul at paul-moore.com>

Reviewed-by: Mimi Zohar <zohar at linux.ibm.com>