The branch stable/13 has been updated by jhb:
URL:
https://cgit.FreeBSD.org/src/commit/?id=80893ea32be08797049b36dc14e2210e40a4f5b8
commit 80893ea32be08797049b36dc14e2210e40a4f5b8
Author: John Baldwin <j...@freebsd.org>
AuthorDate: 2022-05-05 23:40:04 +0000
Commit: John Baldwin <j...@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
