Example:
When executing "df -h" on Core A to view mount information, this
process will traverse inode nodes, thereby holding the inode_lock.
Since the inode type of the mount point may be rpmsgfs, it will fetch statfs
information from another Core B.
Meanwhile, rcS on Core B needs to obtain file information from Core A,
which will be achieved by fetching stat information through rpmsgfs.
When this message arrives at Core A, a deadlock can occur between Core A's
rptun ap and nsh task.
However, both of these places involve read operations only, thus a reader-writer lock
can be utilized to prevent such a deadlock.
Signed-off-by: dongjiuzhu1 <dongjiuzhu1@xiaomi.com>