similar to: improve use_mm / unuse_mm v2

Hi all, this series improves the use_mm / unuse_mm interface by better documenting the assumptions, and my taking the set_fs manipulations spread over the callers into the core API.

Hi all, this series improves the use_mm / unuse_mm interface by better documenting the assumptions, and my taking the set_fs manipulations spread over the callers into the core API.

Switch the function documentation to kerneldoc comments, and add WARN_ON_ONCE asserts that the calling thread is a kernel thread and does not have ->mm set (or has ->mm set in the case of unuse_mm). Also give the functions a kthread_ prefix to better document the use case. Signed-off-by: Christoph Hellwig <hch at lst.de> --- drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h | 4 +--

Switch the function documentation to kerneldoc comments, and add WARN_ON_ONCE asserts that the calling thread is a kernel thread and does not have ->mm set (or has ->mm set in the case of unuse_mm). Also give the functions a kthread_ prefix to better document the use case. Signed-off-by: Christoph Hellwig <hch at lst.de> Acked-by: Felix Kuehling <Felix.Kuehling at amd.com> ---

Some architectures like arm64 and s390 require USER_DS to be set for kernel threads to access user address space, which is the whole purpose of kthread_use_mm, but other like x86 don't. That has lead to a huge mess where some callers are fixed up once they are tested on said architectures, while others linger around and yet other like io_uring try to do "clever" optimizations for

Some architectures like arm64 and s390 require USER_DS to be set for kernel threads to access user address space, which is the whole purpose of kthread_use_mm, but other like x86 don't. That has lead to a huge mess where some callers are fixed up once they are tested on said architectures, while others linger around and yet other like io_uring try to do "clever" optimizations for

On Fri, Nov 2, 2018 at 10:10 AM Linus Torvalds <torvalds at linux-foundation.org> wrote: > > Don't you take over the VM with "use_mm()" when you do the copies? So > yes, it's a kernel thread, but it has a user VM, and though that > should have the user limits. Oooh. *Just* as I sent this, I realized that "use_mm()" doesn't update the thread

On Fri, Nov 02, 2018 at 09:14:51AM -0700, Linus Torvalds wrote: > On Fri, Nov 2, 2018 at 6:04 AM Michael S. Tsirkin <mst at redhat.com> wrote: > > > > I've tried making access_ok mask the parameter it gets. > > PLEASE don't do this. Okay. > Just use "copy_to/from_user()". Just for completeness I'd like to point out for vhost the copies are

On Fri, Nov 02, 2018 at 09:14:51AM -0700, Linus Torvalds wrote: > On Fri, Nov 2, 2018 at 6:04 AM Michael S. Tsirkin <mst at redhat.com> wrote: > > > > I've tried making access_ok mask the parameter it gets. > > PLEASE don't do this. Okay. > Just use "copy_to/from_user()". Just for completeness I'd like to point out for vhost the copies are

These helpers are only for use with kernel threads, and I will tie them more into the kthread infrastructure going forward. Also move the prototypes to kthread.h - mmu_context.h was a little weird to start with as it otherwise contains very low-level MM bits. Signed-off-by: Christoph Hellwig <hch at lst.de> --- drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.h | 1 +

We used to implement the work flushing through tracking queued seq, done seq, and the number of flushing. This patch simplify this by just implement work flushing through another kind of vhost work with completion. This will be used by lockless enqueuing patch. Signed-off-by: Jason Wang <jasowang at redhat.com> --- drivers/vhost/vhost.c | 53

We used to implement the work flushing through tracking queued seq, done seq, and the number of flushing. This patch simplify this by just implement work flushing through another kind of vhost work with completion. This will be used by lockless enqueuing patch. Signed-off-by: Jason Wang <jasowang at redhat.com> --- drivers/vhost/vhost.c | 53

What it is: vhost net is a character device that can be used to reduce the number of system calls involved in virtio networking. Existing virtio net code is used in the guest without modification. There's similarity with vringfd, with some differences and reduced scope - uses eventfd for signalling - structures can be moved around in memory at any time (good for migration) - support memory

What it is: vhost net is a character device that can be used to reduce the number of system calls involved in virtio networking. Existing virtio net code is used in the guest without modification. There's similarity with vringfd, with some differences and reduced scope - uses eventfd for signalling - structures can be moved around in memory at any time (good for migration) - support memory

vhost net module wants to do copy to/from user from a kernel thread, which needs use_mm (like what fs/aio has). Move that into mm/ and export to modules. Acked-by: Andrew Morton <akpm at linux-foundation.org> Acked-by: Andrea Arcangeli <aarcange at redhat.com> Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- fs/aio.c | 47

vhost net module wants to do copy to/from user from a kernel thread, which needs use_mm (like what fs/aio has). Move that into mm/ and export to modules. Acked-by: Andrew Morton <akpm at linux-foundation.org> Acked-by: Andrea Arcangeli <aarcange at redhat.com> Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- fs/aio.c | 47

On Thu, Mar 2, 2023 at 7:35?PM Stefano Garzarella <sgarzare at redhat.com> wrote: > > The new "use_va" module parameter (default: false) is used in > vdpa_alloc_device() to inform the vDPA framework that the device > supports VA. > > vringh is initialized to use VA only when "use_va" is true and the > user's mm has been bound. So, only when the

On Thu, Apr 16, 2020 at 07:31:55AM +0200, Christoph Hellwig wrote: > this series improves the use_mm / unuse_mm interface by better > documenting the assumptions, and my taking the set_fs manipulations > spread over the callers into the core API. I appreciate all the work you're doing here. Do you have plans to introduce a better-named API than set_fs() / get_fs()? Also, having

Currently, vhost-net is the only consumer of vhost infrastructure. So vhost infrastructure and vhost-net driver are in a single module. Separating this as a vhost.ko module and a vhost-net.ko module makes it is easier to share code with other vhost drivers, e.g. vhost-blk.ko, tcm-vhost.ko. Signed-off-by: Asias He <asias at redhat.com> --- drivers/vhost/Kconfig | 10 +++++++++-

Currently, vhost-net is the only consumer of vhost infrastructure. So vhost infrastructure and vhost-net driver are in a single module. Separating this as a vhost.ko module and a vhost-net.ko module makes it is easier to share code with other vhost drivers, e.g. vhost-blk.ko, tcm-vhost.ko. Signed-off-by: Asias He <asias at redhat.com> --- drivers/vhost/Kconfig | 10 +++++++++-