kernel/linux.git/arch/um/os-Linux/file.c, branch v6.12.91

um: Fix FD copy size in os_rcv_fd_msg()

2025-09-25T09:13:42+00:00

[ Upstream commit df447a3b4a4b961c9979b4b3ffb74317394b9b40 ] When copying FDs, the copy size should not include the control message header (cmsghdr). Fix it. Fixes: 5cde6096a4dd ("um: generalize os_rcv_fd") Signed-off-by: Tiwei Bie Signed-off-by: Johannes Berg Signed-off-by: Sasha Levin

um: remove variable stack array in os_rcv_fd_msg()

2024-09-12T17:51:26+00:00

When generalizing this, I was in the mindset of this being "userspace" code, but even there we should not use variable arrays as the kernel is moving away from allowing that. Simply reserve (but not use) enough space for the maximum two descriptors we might need now, and return an error if attempting to receive more than that. Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202407041459.3SYg4TEi-lkp@intel.com/ Signed-off-by: Johannes Berg Signed-off-by: Richard Weinberger

um: add mmap/mremap OS calls

2024-07-03T10:24:48+00:00

For the upcoming shared-memory time-travel external optimisations, we need to be able to mmap/mremap. Add the necessary OS calls. Link: https://patch.msgid.link/20240702192118.ca4472963638.Ic2da1d3a983fe57340c1b693badfa9c5bd2d8c61@changeid Signed-off-by: Johannes Berg

um: generalize os_rcv_fd

2024-07-03T10:24:25+00:00

Change os_rcv_fd() to os_rcv_fd_msg() that can more generally receive any number of FDs in any kind of message. Link: https://patch.msgid.link/20240702192118.40b78b2bfe4e.Ic6ec12d72630e5bcae1e597d6bd5c6f29f441563@changeid Signed-off-by: Johannes Berg

um: chan: use blocking IO for console output for time-travel

2024-07-03T10:18:02+00:00

When in time-travel mode (infinite-cpu or external) time should not pass for writing to the console. As such, it makes sense to put the FD for the output side into blocking mode and simply let any write to it hang. If we did not do this, then time could pass waiting for the console to become writable again. This is not desirable as it has random effects on the clock between runs. Implement this by duplicating the FD if output is active in a relevant mode and setting the duplicate to be blocking. This avoids changing the input channel to be blocking should it exists. After this, use the blocking FD for all write operations and do not allocate an IRQ it is set. Without time-travel mode fd_out will always match fd_in and IRQs are registered. Signed-off-by: Benjamin Berg Link: https://patch.msgid.link/20231018123643.1255813-4-benjamin@sipsolutions.net Signed-off-by: Johannes Berg

um: Fix WRITE_ZEROES in the UBD Driver

2022-03-11T09:46:34+00:00

Call to fallocate with FALLOC_FL_PUNCH_HOLE on a device backed by a sparse file can end up by missing data, zeroes data range, if the underlying file is used with a tool like bmaptool which will referenced only used spaces. Signed-off-by: Frédéric Danis Acked-by: Anton Ivanov Signed-off-by: Richard Weinberger

um: Use fdatasync() when mapping the UBD FSYNC command

2020-06-02T20:37:55+00:00

We do not need to update the metadata (atime, mtime, etc) on the UBD file and/or the COW file until UML exits. UBD image mtime is checked in UML only when opening the files. After that they are locked and used exclusively by a single UML instance, so there is no point wasting resources on updating metadata on every sync. We can sync data only. The host will always update mtime if a file has been modified upon closing it. Signed-off-by: Anton Ivanov Signed-off-by: Richard Weinberger

um: Add include: memset() and memcpy() are in

2020-06-02T20:37:11+00:00

These two functions are otherwise unknown to the pedantic compiler. Include the correct header to enable the build to succeed. Signed-off-by: Zach van Rijn Acked-By: Anton Ivanov Signed-off-by: Richard Weinberger

um: Implement time-travel=ext

2020-03-29T21:29:08+00:00

This implements synchronized time-travel mode which - using a special application on a unix socket - lets multiple machines take part in a time-travelling simulation together. The protocol for the unix domain socket is defined in the new file include/uapi/linux/um_timetravel.h. Signed-off-by: Johannes Berg Signed-off-by: Richard Weinberger

um: falloc.h needs to be directly included for older libc

2020-03-29T21:21:42+00:00

When building UML with glibc 2.17 installed, compilation of arch/um/os-Linux/file.c fails due to failure to find FALLOC_FL_PUNCH_HOLE and FALLOC_FL_KEEP_SIZE definitions. It appears that /usr/include/bits/fcntl-linux.h (indirectly included by /usr/include/fcntl.h) does not include falloc.h with an older glibc, whereas a more up-to-date version does. Adding the direct include to file.c resolves the issue and does not cause problems for more recent glibc. Fixes: 50109b5a03b4 ("um: Add support for DISCARD in the UBD Driver") Cc: Brendan Higgins Signed-off-by: Alan Maguire Reviewed-by: Brendan Higgins Acked-By: Anton Ivanov Signed-off-by: Richard Weinberger