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5d10777c46
insertion of a CF card, for random values of N > 1. With these fixes, I've been able to do 100 insert/remove of the cards w/o a crash with lots of system activity going on that in the past would help trigger the crash. The problem: FreeBSD creates dev_t's on the fly as they are needed and never destroys them. These dev_t's point to a struct disk that is used for housekeeping on the disk. When a device goes away, the struct disk pointer becomes a dangling pointer. Sometimes when the device comes back, the pointer will point to the new struct disk (in which case the insertion will work). Other times it won't (especially if any length of time has passed, since it is dependent on memory returned from malloc). The Fix: There is one of these dev_t's that is always correct. The device for the WHOLE_DISK_SLICE is always right. It gets set at create_disk() time. So, the fix is to spend a little CPU time and lookup the WHOLE_DISK_SLICE dev_t and use the si_disk from that in preference to the one that's in the device asking to do the I/O. In addition, we change the test of si_disk == NULL meaning that the dev needed to inherit properties from the pdev to dev->si_disk != pdev->si_disk. This test is a little stronger than the previous test, but can sometimes be fooled into not inheriting. However, the results of this fooling are that the old values will be used, which will generally always be the same as before. si_drv[12] are the only values that are copied that might pose a problem. They tend to change as the si_disk field would change, so it is a hole, but it is a small hole. One could correctly argue that one should replace much of this code with something much much better. I would be on the pro side of that argument. Reviewed by: phk (who also ported the original patch to current) Sponsored by: Timing Solutions
299 lines
6.5 KiB
C
299 lines
6.5 KiB
C
/*
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* ----------------------------------------------------------------------------
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* "THE BEER-WARE LICENSE" (Revision 42):
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* <phk@FreeBSD.ORG> wrote this file. As long as you retain this notice you
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* can do whatever you want with this stuff. If we meet some day, and you think
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* this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
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* ----------------------------------------------------------------------------
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*
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* $FreeBSD$
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*
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/sysctl.h>
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#include <sys/bio.h>
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#include <sys/conf.h>
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#include <sys/disk.h>
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#include <sys/malloc.h>
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#include <sys/sysctl.h>
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#include <machine/md_var.h>
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MALLOC_DEFINE(M_DISK, "disk", "disk data");
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static d_strategy_t diskstrategy;
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static d_open_t diskopen;
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static d_close_t diskclose;
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static d_ioctl_t diskioctl;
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static d_psize_t diskpsize;
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static LIST_HEAD(, disk) disklist = LIST_HEAD_INITIALIZER(&disklist);
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static void
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inherit_raw(dev_t pdev, dev_t dev)
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{
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dev->si_disk = pdev->si_disk;
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dev->si_drv1 = pdev->si_drv1;
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dev->si_drv2 = pdev->si_drv2;
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dev->si_iosize_max = pdev->si_iosize_max;
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dev->si_bsize_phys = pdev->si_bsize_phys;
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dev->si_bsize_best = pdev->si_bsize_best;
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}
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dev_t
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disk_create(int unit, struct disk *dp, int flags, struct cdevsw *cdevsw, struct cdevsw *proto)
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{
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dev_t dev;
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bzero(dp, sizeof(*dp));
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dev = makedev(cdevsw->d_maj, 0);
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if (!devsw(dev)) {
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*proto = *cdevsw;
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proto->d_open = diskopen;
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proto->d_close = diskclose;
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proto->d_ioctl = diskioctl;
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proto->d_strategy = diskstrategy;
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proto->d_psize = diskpsize;
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cdevsw_add(proto);
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}
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if (bootverbose)
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printf("Creating DISK %s%d\n", cdevsw->d_name, unit);
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dev = make_dev(proto, dkmakeminor(unit, WHOLE_DISK_SLICE, RAW_PART),
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0, 0, 0, "%s%d", cdevsw->d_name, unit);
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dev->si_disk = dp;
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dp->d_dev = dev;
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dp->d_dsflags = flags;
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dp->d_devsw = cdevsw;
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LIST_INSERT_HEAD(&disklist, dp, d_list);
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return (dev);
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}
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int
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disk_dumpcheck(dev_t dev, u_int *count, u_int *blkno, u_int *secsize)
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{
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struct disk *dp;
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struct disklabel *dl;
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u_int boff;
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dp = dev->si_disk;
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if (!dp)
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return (ENXIO);
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if (!dp->d_slice)
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return (ENXIO);
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dl = dsgetlabel(dev, dp->d_slice);
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if (!dl)
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return (ENXIO);
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*count = (u_long)Maxmem * PAGE_SIZE / dl->d_secsize;
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if (dumplo < 0 ||
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(dumplo + *count > dl->d_partitions[dkpart(dev)].p_size))
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return (EINVAL);
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boff = dl->d_partitions[dkpart(dev)].p_offset +
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dp->d_slice->dss_slices[dkslice(dev)].ds_offset;
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*blkno = boff + dumplo;
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*secsize = dl->d_secsize;
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return (0);
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}
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void
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disk_invalidate (struct disk *disk)
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{
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if (disk->d_slice)
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dsgone(&disk->d_slice);
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}
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void
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disk_destroy(dev_t dev)
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{
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LIST_REMOVE(dev->si_disk, d_list);
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bzero(dev->si_disk, sizeof(*dev->si_disk));
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dev->si_disk = NULL;
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destroy_dev(dev);
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return;
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}
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struct disk *
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disk_enumerate(struct disk *disk)
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{
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if (!disk)
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return (LIST_FIRST(&disklist));
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else
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return (LIST_NEXT(disk, d_list));
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}
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static int
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sysctl_disks(SYSCTL_HANDLER_ARGS)
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{
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struct disk *disk;
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int error, first;
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disk = NULL;
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first = 1;
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while ((disk = disk_enumerate(disk))) {
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if (!first) {
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error = SYSCTL_OUT(req, " ", 1);
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if (error)
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return error;
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} else {
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first = 0;
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}
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error = SYSCTL_OUT(req, disk->d_dev->si_name, strlen(disk->d_dev->si_name));
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if (error)
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return error;
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}
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error = SYSCTL_OUT(req, "", 1);
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return error;
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}
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SYSCTL_PROC(_kern, OID_AUTO, disks, CTLTYPE_STRING | CTLFLAG_RD, 0, NULL,
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sysctl_disks, "A", "names of available disks");
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/*
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* The cdevsw functions
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*/
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static int
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diskopen(dev_t dev, int oflags, int devtype, struct proc *p)
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{
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dev_t pdev;
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struct disk *dp;
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int error;
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error = 0;
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pdev = dkmodpart(dkmodslice(dev, WHOLE_DISK_SLICE), RAW_PART);
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dp = pdev->si_disk;
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if (!dp)
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return (ENXIO);
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while (dp->d_flags & DISKFLAG_LOCK) {
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dp->d_flags |= DISKFLAG_WANTED;
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error = tsleep(dp, PRIBIO | PCATCH, "diskopen", hz);
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if (error)
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return (error);
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}
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dp->d_flags |= DISKFLAG_LOCK;
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if (!dsisopen(dp->d_slice)) {
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if (!pdev->si_iosize_max)
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pdev->si_iosize_max = dev->si_iosize_max;
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error = dp->d_devsw->d_open(pdev, oflags, devtype, p);
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}
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/* Inherit properties from the whole/raw dev_t */
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inherit_raw(pdev, dev);
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if (error)
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goto out;
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error = dsopen(dev, devtype, dp->d_dsflags, &dp->d_slice, &dp->d_label);
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if (!dsisopen(dp->d_slice))
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dp->d_devsw->d_close(pdev, oflags, devtype, p);
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out:
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dp->d_flags &= ~DISKFLAG_LOCK;
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if (dp->d_flags & DISKFLAG_WANTED) {
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dp->d_flags &= ~DISKFLAG_WANTED;
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wakeup(dp);
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}
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return(error);
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}
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static int
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diskclose(dev_t dev, int fflag, int devtype, struct proc *p)
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{
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struct disk *dp;
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int error;
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dev_t pdev;
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error = 0;
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pdev = dkmodpart(dkmodslice(dev, WHOLE_DISK_SLICE), RAW_PART);
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dp = pdev->si_disk;
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dsclose(dev, devtype, dp->d_slice);
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if (!dsisopen(dp->d_slice)) {
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error = dp->d_devsw->d_close(dp->d_dev, fflag, devtype, p);
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}
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return (error);
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}
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static void
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diskstrategy(struct bio *bp)
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{
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dev_t pdev;
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struct disk *dp;
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pdev = dkmodpart(dkmodslice(bp->bio_dev, WHOLE_DISK_SLICE), RAW_PART);
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dp = pdev->si_disk;
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if (dp != bp->bio_dev->si_disk)
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inherit_raw(pdev, bp->bio_dev);
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if (!dp) {
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bp->bio_error = ENXIO;
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bp->bio_flags |= BIO_ERROR;
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biodone(bp);
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return;
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}
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if (dscheck(bp, dp->d_slice) <= 0) {
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biodone(bp);
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return;
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}
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KASSERT(dp->d_devsw != NULL, ("NULL devsw"));
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KASSERT(dp->d_devsw->d_strategy != NULL, ("NULL d_strategy"));
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dp->d_devsw->d_strategy(bp);
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return;
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}
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static int
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diskioctl(dev_t dev, u_long cmd, caddr_t data, int fflag, struct proc *p)
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{
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struct disk *dp;
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int error;
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dev_t pdev;
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pdev = dkmodpart(dkmodslice(dev, WHOLE_DISK_SLICE), RAW_PART);
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dp = pdev->si_disk;
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error = dsioctl(dev, cmd, data, fflag, &dp->d_slice);
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if (error == ENOIOCTL)
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error = dp->d_devsw->d_ioctl(dev, cmd, data, fflag, p);
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return (error);
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}
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static int
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diskpsize(dev_t dev)
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{
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struct disk *dp;
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dev_t pdev;
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pdev = dkmodpart(dkmodslice(dev, WHOLE_DISK_SLICE), RAW_PART);
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dp = pdev->si_disk;
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if (!dp)
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return (-1);
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if (dp != dev->si_disk) {
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dev->si_drv1 = pdev->si_drv1;
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dev->si_drv2 = pdev->si_drv2;
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/* XXX: don't set bp->b_dev->si_disk (?) */
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}
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return (dssize(dev, &dp->d_slice));
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}
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SYSCTL_DECL(_debug_sizeof);
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SYSCTL_INT(_debug_sizeof, OID_AUTO, disklabel, CTLFLAG_RD,
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0, sizeof(struct disklabel), "sizeof(struct disklabel)");
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SYSCTL_INT(_debug_sizeof, OID_AUTO, diskslices, CTLFLAG_RD,
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0, sizeof(struct diskslices), "sizeof(struct diskslices)");
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SYSCTL_INT(_debug_sizeof, OID_AUTO, disk, CTLFLAG_RD,
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0, sizeof(struct disk), "sizeof(struct disk)");
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