nuttx/Kconfig at 0b860726db80019186a2f442f86fcda93b4e2adc - nuttx - Owlcode Community Gitea

sergiotarxz/nuttx

Gregory Nutt 7deb24484c This comment converts the underlying IPC used by the UserFS from Unix domain local sockets to UDP LocalHost loopback sockets. The problem with the local sockets is that they do require operations on the top level psuedo-file system inode tree. That tree must be locked during certain traversals such as enumerate mountpoints or enumerating directory entries.

This conversion is unfortunate in the sense that Unix local domain sockets are relatively lightweight.  LocalHost UDP sockets are much heavier weight since they rely on the full UDP stack.  If anyone is up for a complete redesign, then using some shared memory and a POSIX message queue would be lightweight again.

This commit also fixes several bugs that were not testable before the inode tree deadlock.  I cannot say that the logic is 100% stable but it does not have basic functionality.

Squashed commit of the following:

    fs/userfs:  Order locking so that access to the shared I/O buffer is also locked.
    fs/userfs:  Converts to use LocalHost UDP loopback for IPC.

2017-11-05 12:25:58 -06:00

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 #
 # For a description of the syntax of this configuration file,
 # see the file kconfig-language.txt in the NuttX tools repository.
 #
 config FS_USERFS
 	bool "User file system"
 	default n
 	depends on NET_IPv4 && NET_UDP && NETDEV_LOOPBACK
 	---help---
 		Enable support for user file system.  See include/nuttx/fs/userfs.h
 if FS_USERFS
 endif