git: 80893ea32be0 - stable/13 - pbio: Add locking and remove D_NEEDGIANT.
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Date: Fri, 20 May 2022 00:21:05 UTC
The branch stable/13 has been updated by jhb: URL: https://cgit.FreeBSD.org/src/commit/?id=80893ea32be08797049b36dc14e2210e40a4f5b8 commit 80893ea32be08797049b36dc14e2210e40a4f5b8 Author: John Baldwin <jhb@FreeBSD.org> AuthorDate: 2022-05-05 23:40:04 +0000 Commit: John Baldwin <jhb@FreeBSD.org> CommitDate: 2022-05-19 22:01:50 +0000 pbio: Add locking and remove D_NEEDGIANT. Use a sx lock to permit uiomove directly into/out of the the per-port buffers. In addition, the sx lock provides a stronger guarantee that I think this driver wants which is to single-thread read and write calls even while paused. Finally, replace tsleep with dummy wait channels with calls to pause_sig to more clearly communicate the intent. Differential Revision: https://reviews.freebsd.org/D35081 (cherry picked from commit 51f481235c29fb38b92fb08a830385e39df80093) --- sys/dev/pbio/pbio.c | 54 ++++++++++++++++++++++++++++++----------------------- 1 file changed, 31 insertions(+), 23 deletions(-) diff --git a/sys/dev/pbio/pbio.c b/sys/dev/pbio/pbio.c index 516ec3a73408..0fd841cd5720 100644 --- a/sys/dev/pbio/pbio.c +++ b/sys/dev/pbio/pbio.c @@ -49,6 +49,7 @@ __FBSDID("$FreeBSD$"); #include <dev/pbio/pbioio.h> /* pbio IOCTL definitions */ #include <sys/uio.h> #include <sys/fcntl.h> +#include <sys/sx.h> #include <isa/isavar.h> /* Function prototypes (these should all be static) */ @@ -84,11 +85,8 @@ static char *port_names[] = {"a", "b", "ch", "cl"}; #define pbio_addr(dev) ((dev)->si_drv1) -#define PBIOPRI ((PZERO + 5) | PCATCH) - static struct cdevsw pbio_cdevsw = { .d_version = D_VERSION, - .d_flags = D_NEEDGIANT, .d_open = pbioopen, .d_read = pbioread, .d_write = pbiowrite, @@ -117,6 +115,7 @@ struct pbio_softc { int iomode; /* Virtualized I/O mode port value */ /* The real port is write-only */ struct resource *res; + struct sx lock; }; typedef struct pbio_softc *sc_p; @@ -230,6 +229,7 @@ pbioattach (device_t dev) */ sc->iomode = 0x9b; /* All ports to input */ + sx_init(&sc->lock, "pbio"); for (i = 0; i < PBIO_NPORTS; i++) { make_dev_args_init(&args); args.mda_devsw = &pbio_cdevsw; @@ -249,10 +249,12 @@ pbioioctl (struct cdev *dev, u_long cmd, caddr_t data, int flag, struct thread *td) { struct pbio_softc *scp; - int port; + int error, port; + error = 0; port = PORT(dev); scp = pbio_addr(dev); + sx_xlock(&scp->lock); switch (cmd) { case PBIO_SETDIFF: scp->pd[port].diff = *(int *)data; @@ -273,16 +275,17 @@ pbioioctl (struct cdev *dev, u_long cmd, caddr_t data, int flag, *(int *)data = scp->pd[port].opace; break; default: - return ENXIO; + error = ENXIO; } - return (0); + sx_xunlock(&scp->lock); + return (error); } static int pbioopen(struct cdev *dev, int oflags, int devtype, struct thread *td) { struct pbio_softc *scp; - int ocfg, port; + int error, ocfg, port; int portbit; /* Port configuration bit */ port = PORT(dev); @@ -297,6 +300,8 @@ pbioopen(struct cdev *dev, int oflags, int devtype, struct thread *td) } ocfg = scp->iomode; + error = 0; + sx_xlock(&scp->lock); if (oflags & FWRITE) /* Writing == output; zero the bit */ pboutb(scp, PBIO_CFG, scp->iomode = (ocfg & (~portbit))); @@ -304,9 +309,10 @@ pbioopen(struct cdev *dev, int oflags, int devtype, struct thread *td) /* Reading == input; set the bit */ pboutb(scp, PBIO_CFG, scp->iomode = (ocfg | portbit)); else - return (EACCES); + error = EACCES; + sx_xunlock(&scp->lock); - return (0); + return (error); } /* @@ -341,8 +347,7 @@ portval(int port, struct pbio_softc *scp, char *val) scp->pd[port].oldval = *val; return (0); } - err = tsleep((caddr_t)&(scp->pd[port].diff), PBIOPRI, - "pbiopl", max(1, scp->pd[port].ipace)); + err = pause_sig("pbiopl", max(1, scp->pd[port].ipace)); if (err == EINTR) return (EINTR); } else @@ -354,26 +359,28 @@ static int pbioread(struct cdev *dev, struct uio *uio, int ioflag) { struct pbio_softc *scp; - int err, i, port, ret, toread; + int err, i, port, toread; char val; port = PORT(dev); scp = pbio_addr(dev); + err = 0; + sx_xlock(&scp->lock); while (uio->uio_resid > 0) { toread = min(uio->uio_resid, PBIO_BUFSIZ); - if ((ret = uiomove(scp->pd[port].buff, toread, uio)) != 0) - return (ret); + if ((err = uiomove(scp->pd[port].buff, toread, uio)) != 0) + break; for (i = 0; i < toread; i++) { if ((err = portval(port, scp, &val)) != 0) - return (err); + break; scp->pd[port].buff[i] = val; if (!scp->pd[port].diff && scp->pd[port].ipace) - tsleep((caddr_t)&(scp->pd[port].ipace), PBIOPRI, - "pbioip", scp->pd[port].ipace); + pause_sig("pbioip", scp->pd[port].ipace); } } - return 0; + sx_xunlock(&scp->lock); + return (err); } static int @@ -386,10 +393,12 @@ pbiowrite(struct cdev *dev, struct uio *uio, int ioflag) port = PORT(dev); scp = pbio_addr(dev); + ret = 0; + sx_xlock(&scp->lock); while (uio->uio_resid > 0) { towrite = min(uio->uio_resid, PBIO_BUFSIZ); if ((ret = uiomove(scp->pd[port].buff, towrite, uio)) != 0) - return (ret); + break; for (i = 0; i < towrite; i++) { val = scp->pd[port].buff[i]; switch (port) { @@ -413,12 +422,11 @@ pbiowrite(struct cdev *dev, struct uio *uio, int ioflag) break; } if (scp->pd[port].opace) - tsleep((caddr_t)&(scp->pd[port].opace), - PBIOPRI, "pbioop", - scp->pd[port].opace); + pause_sig("pbioop", scp->pd[port].opace); } } - return (0); + sx_xunlock(&scp->lock); + return (ret); } static int