instead of malloc(). The SWAP objects are automagically freed when there are no
more consumers. This greatly simplifies the mmap logic inside CUSE(3) in the
kernel. This change fixes an issue where mmapped memory can accumulate and never
get freed, if many different mmap sizes are needed over time. Further this
change fixes memory leaks when the CUSE(3) kernel module is unloaded.
While at it make sure the CUSE_ALLOC_PAGES_MAX limit is treated as an exclusive
limit. CUSE(3) memory maps must be less than CUSE_ALLOC_PAGES_MAX number of pages.
Reviewed by: kib @
Differential Revision: https://reviews.freebsd.org/D11392
Sponsored by: Mellanox Technologies
MFC after: 1 week
function. Many existing clients don't understand POLLNVAL and instead
relies on an error code from the read(), write() or ioctl() system
call. Also make sure we wakeup any client pollers before the cuse
server is closing, so they don't wait forever for an event.
The CUSE library is a wrapper for the devfs kernel functionality which
is exposed through /dev/cuse . In order to function the CUSE kernel
code must either be enabled in the kernel configuration file or loaded
separately as a module. Currently none of the committed items are
connected to the default builds, except for installing the needed
header files. The CUSE code will be connected to the default world and
kernel builds in a follow-up commit.
The CUSE module was written by Hans Petter Selasky, somewhat inspired
by similar functionality found in FUSE. The CUSE library can be used
for many purposes. Currently CUSE is used when running Linux kernel
drivers in user-space, which need to create a character device node to
communicate with its applications. CUSE has full support for almost
all devfs functionality found in the kernel:
- kevents
- read
- write
- ioctl
- poll
- open
- close
- mmap
- private per file handle data
Requested by several people. Also see "multimedia/cuse4bsd-kmod" in
ports.
