ping
> On 27 Sep 2023, at 16:07, Vitaliy Makkoveev <m...@openbsd.org> wrote:
>
> Introduce `fd_mtx' mutex(9) and use it for `fd_fbufs_in' fuse buffers
> queue and `fd_rklist' knotes list protection.
>
> Index: sys/miscfs/fuse/fuse_device.c
> ===================================================================
> RCS file: /cvs/src/sys/miscfs/fuse/fuse_device.c,v
> retrieving revision 1.39
> diff -u -p -r1.39 fuse_device.c
> --- sys/miscfs/fuse/fuse_device.c 8 Sep 2023 20:00:28 -0000 1.39
> +++ sys/miscfs/fuse/fuse_device.c 27 Sep 2023 13:05:55 -0000
> @@ -19,13 +19,14 @@
> #include <sys/systm.h>
> #include <sys/fcntl.h>
> #include <sys/ioctl.h>
> +#include <sys/event.h>
> #include <sys/malloc.h>
> #include <sys/mount.h>
> +#include <sys/mutex.h>
> #include <sys/stat.h>
> #include <sys/statvfs.h>
> #include <sys/vnode.h>
> #include <sys/fusebuf.h>
> -#include <sys/selinfo.h>
>
> #include "fusefs_node.h"
> #include "fusefs.h"
> @@ -36,18 +37,24 @@
> #define DPRINTF(fmt, arg...)
> #endif
>
> +/*
> + * Locks used to protect struct members and global data
> + * m fd_mtx
> + */
> +
> SIMPLEQ_HEAD(fusebuf_head, fusebuf);
>
> struct fuse_d {
> + struct mutex fd_mtx;
> struct fusefs_mnt *fd_fmp;
> int fd_unit;
>
> /*fusebufs queues*/
> - struct fusebuf_head fd_fbufs_in;
> + struct fusebuf_head fd_fbufs_in; /* [m] */
> struct fusebuf_head fd_fbufs_wait;
>
> /* kq fields */
> - struct selinfo fd_rsel;
> + struct klist fd_rklist; /* [m] */
> LIST_ENTRY(fuse_d) fd_list;
> };
>
> @@ -67,12 +74,16 @@ int fusewrite(dev_t, struct uio *, int);
> int fusekqfilter(dev_t dev, struct knote *kn);
> int filt_fuse_read(struct knote *, long);
> void filt_fuse_rdetach(struct knote *);
> +int filt_fuse_modify(struct kevent *, struct knote *);
> +int filt_fuse_process(struct knote *, struct kevent *);
>
> static const struct filterops fuse_rd_filtops = {
> - .f_flags = FILTEROP_ISFD,
> + .f_flags = FILTEROP_ISFD | FILTEROP_MPSAFE,
> .f_attach = NULL,
> .f_detach = filt_fuse_rdetach,
> .f_event = filt_fuse_read,
> + .f_modify = filt_fuse_modify,
> + .f_process = filt_fuse_process,
> };
>
> #ifdef FUSE_DEBUG
> @@ -142,6 +153,7 @@ fuse_device_cleanup(dev_t dev)
>
> /* clear FIFO IN */
> lprev = NULL;
> + mtx_enter(&fd->fd_mtx);
> SIMPLEQ_FOREACH_SAFE(f, &fd->fd_fbufs_in, fb_next, ftmp) {
> DPRINTF("cleanup unprocessed msg in sc_fbufs_in\n");
> if (lprev == NULL)
> @@ -155,6 +167,7 @@ fuse_device_cleanup(dev_t dev)
> wakeup(f);
> lprev = f;
> }
> + mtx_leave(&fd->fd_mtx);
>
> /* clear FIFO WAIT*/
> lprev = NULL;
> @@ -182,9 +195,11 @@ fuse_device_queue_fbuf(dev_t dev, struct
> if (fd == NULL)
> return;
>
> + mtx_enter(&fd->fd_mtx);
> SIMPLEQ_INSERT_TAIL(&fd->fd_fbufs_in, fbuf, fb_next);
> + knote_locked(&fd->fd_rklist, 0);
> + mtx_leave(&fd->fd_mtx);
> stat_fbufs_in++;
> - selwakeup(&fd->fd_rsel);
> }
>
> void
> @@ -221,6 +236,9 @@ fuseopen(dev_t dev, int flags, int fmt,
> fd->fd_unit = unit;
> SIMPLEQ_INIT(&fd->fd_fbufs_in);
> SIMPLEQ_INIT(&fd->fd_fbufs_wait);
> + mtx_init(&fd->fd_mtx, IPL_MPFLOOR);
> + klist_init_mutex(&fd->fd_rklist, &fd->fd_mtx);
> +
> LIST_INSERT_HEAD(&fuse_d_list, fd, fd_list);
>
> stat_opened_fusedev++;
> @@ -278,6 +296,7 @@ fuseioctl(dev_t dev, u_long cmd, caddr_t
> ioexch = (struct fb_ioctl_xch *)addr;
>
> /* Looking for uuid in fd_fbufs_in */
> + mtx_enter(&fd->fd_mtx);
> SIMPLEQ_FOREACH(fbuf, &fd->fd_fbufs_in, fb_next) {
> if (fbuf->fb_uuid == ioexch->fbxch_uuid)
> break;
> @@ -285,6 +304,7 @@ fuseioctl(dev_t dev, u_long cmd, caddr_t
> lastfbuf = fbuf;
> }
> if (fbuf == NULL) {
> + mtx_leave(&fd->fd_mtx);
> printf("fuse: Cannot find fusebuf\n");
> return (EINVAL);
> }
> @@ -295,6 +315,8 @@ fuseioctl(dev_t dev, u_long cmd, caddr_t
> else
> SIMPLEQ_REMOVE_AFTER(&fd->fd_fbufs_in, lastfbuf,
> fb_next);
> + mtx_leave(&fd->fd_mtx);
> +
> stat_fbufs_in--;
>
> /* Do not handle fbufs with bad len */
> @@ -389,13 +411,17 @@ fuseread(dev_t dev, struct uio *uio, int
> if (fd == NULL)
> return (ENXIO);
>
> + mtx_enter(&fd->fd_mtx);
> if (SIMPLEQ_EMPTY(&fd->fd_fbufs_in)) {
> + mtx_leave(&fd->fd_mtx);
> +
> if (ioflag & O_NONBLOCK)
> return (EAGAIN);
>
> goto end;
> }
> fbuf = SIMPLEQ_FIRST(&fd->fd_fbufs_in);
> + mtx_leave(&fd->fd_mtx);
>
> /* We get the whole fusebuf or nothing */
> if (uio->uio_resid != FUSEBUFSIZE)
> @@ -419,7 +445,9 @@ fuseread(dev_t dev, struct uio *uio, int
>
> /* Remove the fbuf if it does not contains data */
> if (fbuf->fb_len == 0) {
> + mtx_enter(&fd->fd_mtx);
> SIMPLEQ_REMOVE_HEAD(&fd->fd_fbufs_in, fb_next);
> + mtx_leave(&fd->fd_mtx);
> stat_fbufs_in--;
> SIMPLEQ_INSERT_TAIL(&fd->fd_fbufs_wait, fbuf, fb_next);
> stat_fbufs_wait++;
> @@ -519,7 +547,7 @@ fusekqfilter(dev_t dev, struct knote *kn
>
> switch (kn->kn_filter) {
> case EVFILT_READ:
> - klist = &fd->fd_rsel.si_note;
> + klist = &fd->fd_rklist;
> kn->kn_fop = &fuse_rd_filtops;
> break;
> case EVFILT_WRITE:
> @@ -530,7 +558,7 @@ fusekqfilter(dev_t dev, struct knote *kn
>
> kn->kn_hook = fd;
>
> - klist_insert_locked(klist, kn);
> + klist_insert(klist, kn);
>
> return (0);
> }
> @@ -539,9 +567,9 @@ void
> filt_fuse_rdetach(struct knote *kn)
> {
> struct fuse_d *fd = kn->kn_hook;
> - struct klist *klist = &fd->fd_rsel.si_note;
> + struct klist *klist = &fd->fd_rklist;
>
> - klist_remove_locked(klist, kn);
> + klist_remove(klist, kn);
> }
>
> int
> @@ -554,4 +582,30 @@ filt_fuse_read(struct knote *kn, long hi
> event = 1;
>
> return (event);
> +}
> +
> +int
> +filt_fuse_modify(struct kevent *kev, struct knote *kn)
> +{
> + struct fuse_d *fd = kn->kn_hook;
> + int active;
> +
> + mtx_enter(&fd->fd_mtx);
> + active = knote_modify(kev, kn);
> + mtx_leave(&fd->fd_mtx);
> +
> + return (active);
> +}
> +
> +int
> +filt_fuse_process(struct knote *kn, struct kevent *kev)
> +{
> + struct fuse_d *fd = kn->kn_hook;
> + int active;
> +
> + mtx_enter(&fd->fd_mtx);
> + active = knote_process(kn, kev);
> + mtx_leave(&fd->fd_mtx);
> +
> + return (active);
> }
>
