Add dev_strategy_csw() function, which is similar to dev_strategy()
but assumes that a thread reference was already obtained on the passed device. Use the function from physio(), to avoid two extra dev_mtx lock and unlock. Note that physio() is always used as the cdevsw method, or is called from a cdevsw method, and the caller already owns the reference. dev_strategy() is left to keep KPI intact, but now it is implemented as a wrapper around dev_strategy_csw(). Do some style cleanup in physio(). Requested and reviewed by: kan (previous version) Sponsored by: The FreeBSD Foundation MFC after: 2 weeks
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parent
88c8c0a70f
commit
d1e99f43ed
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=248792
@ -34,11 +34,11 @@ __FBSDID("$FreeBSD$");
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int
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physio(struct cdev *dev, struct uio *uio, int ioflag)
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{
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int i;
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int error;
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struct buf *bp;
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struct cdevsw *csw;
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caddr_t sa;
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u_int iolen;
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struct buf *bp;
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int error, i, mapped;
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/* Keep the process UPAGES from being swapped. XXX: why ? */
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PHOLD(curproc);
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@ -91,11 +91,8 @@ physio(struct cdev *dev, struct uio *uio, int ioflag)
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bp->b_blkno = btodb(bp->b_offset);
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csw = dev->si_devsw;
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if (uio->uio_segflg == UIO_USERSPACE) {
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struct cdevsw *csw;
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int mapped;
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csw = dev->si_devsw;
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if (csw != NULL &&
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(csw->d_flags & D_UNMAPPED_IO) != 0)
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mapped = 0;
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@ -107,7 +104,7 @@ physio(struct cdev *dev, struct uio *uio, int ioflag)
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}
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}
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dev_strategy(dev, bp);
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dev_strategy_csw(dev, csw, bp);
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if (uio->uio_rw == UIO_READ)
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bwait(bp, PRIBIO, "physrd");
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else
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@ -3687,11 +3687,34 @@ void
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dev_strategy(struct cdev *dev, struct buf *bp)
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{
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struct cdevsw *csw;
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struct bio *bip;
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int ref;
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if ((!bp->b_iocmd) || (bp->b_iocmd & (bp->b_iocmd - 1)))
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panic("b_iocmd botch");
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KASSERT(dev->si_refcount > 0,
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("dev_strategy on un-referenced struct cdev *(%s) %p",
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devtoname(dev), dev));
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csw = dev_refthread(dev, &ref);
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dev_strategy_csw(dev, csw, bp);
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dev_relthread(dev, ref);
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}
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void
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dev_strategy_csw(struct cdev *dev, struct cdevsw *csw, struct buf *bp)
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{
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struct bio *bip;
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KASSERT(bp->b_iocmd == BIO_READ || bp->b_iocmd == BIO_WRITE,
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("b_iocmd botch"));
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KASSERT(((dev->si_flags & SI_ETERNAL) != 0 && csw != NULL) ||
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dev->si_threadcount > 0,
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("dev_strategy_csw threadcount cdev *(%s) %p", devtoname(dev),
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dev));
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if (csw == NULL) {
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bp->b_error = ENXIO;
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bp->b_ioflags = BIO_ERROR;
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bufdone(bp);
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return;
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}
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for (;;) {
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bip = g_new_bio();
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if (bip != NULL)
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@ -3707,19 +3730,7 @@ dev_strategy(struct cdev *dev, struct buf *bp)
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bip->bio_done = bufdonebio;
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bip->bio_caller2 = bp;
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bip->bio_dev = dev;
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KASSERT(dev->si_refcount > 0,
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("dev_strategy on un-referenced struct cdev *(%s)",
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devtoname(dev)));
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csw = dev_refthread(dev, &ref);
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if (csw == NULL) {
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g_destroy_bio(bip);
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bp->b_error = ENXIO;
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bp->b_ioflags = BIO_ERROR;
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bufdone(bp);
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return;
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}
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(*csw->d_strategy)(bip);
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dev_relthread(dev, ref);
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}
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/*
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@ -255,6 +255,7 @@ void dev_ref(struct cdev *dev);
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void dev_refl(struct cdev *dev);
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void dev_rel(struct cdev *dev);
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void dev_strategy(struct cdev *dev, struct buf *bp);
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void dev_strategy_csw(struct cdev *dev, struct cdevsw *csw, struct buf *bp);
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struct cdev *make_dev(struct cdevsw *_devsw, int _unit, uid_t _uid, gid_t _gid,
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int _perms, const char *_fmt, ...) __printflike(6, 7);
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struct cdev *make_dev_cred(struct cdevsw *_devsw, int _unit,
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