Date: Tue, 25 Feb 2025 11:48:22 GMT From: Christos Margiolis <christos@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: fd906e47b18f - main - sound: Simplify locking during device creation Message-ID: <202502251148.51PBmMcO051134@gitrepo.freebsd.org>
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The branch main has been updated by christos: URL: https://cgit.FreeBSD.org/src/commit/?id=fd906e47b18f53b09524647bf8431dc6170b8dfd commit fd906e47b18f53b09524647bf8431dc6170b8dfd Author: Christos Margiolis <christos@FreeBSD.org> AuthorDate: 2025-02-25 11:44:24 +0000 Commit: Christos Margiolis <christos@FreeBSD.org> CommitDate: 2025-02-25 11:44:24 +0000 sound: Simplify locking during device creation The mechanism of acquiring SD_F_BUSY in pcm_init() and releasing it in pcm_register() is a leftover from the previous device creation scheme, where pcm_init() (previously pcm_register()) would create the sysctl nodes, as well as the device node. In this scenario, acquiring SD_F_BUSY was necessary, in order to avoid races in case the device was accessed before it was ready for use. Commit 66f3eb14e955 ("sound: Move sysctl and /dev/dspX creation to pcm_setstatus()") fixed this issue, so we can simplify things now. Only acquire SD_F_BUSY in pcm_addchan(), because chn_init() expects to be called with SD_F_BUSY acquired. While here, move the sndstat_register() call further down to be more robust. Sponsored by: The FreeBSD Foundation MFC after: 1 week Reviewed by: markj Differential Revision: https://reviews.freebsd.org/D48482 --- sys/dev/sound/pcm/sound.c | 17 +++++------------ 1 file changed, 5 insertions(+), 12 deletions(-) diff --git a/sys/dev/sound/pcm/sound.c b/sys/dev/sound/pcm/sound.c index c0934dde7718..3e76626f5c57 100644 --- a/sys/dev/sound/pcm/sound.c +++ b/sys/dev/sound/pcm/sound.c @@ -136,9 +136,9 @@ pcm_addchan(device_t dev, int dir, kobj_class_t cls, void *devinfo) struct snddev_info *d = device_get_softc(dev); struct pcm_channel *ch; - PCM_BUSYASSERT(d); - PCM_LOCK(d); + PCM_WAIT(d); + PCM_ACQUIRE(d); ch = chn_init(d, NULL, cls, dir, devinfo); if (!ch) { device_printf(d->dev, "chn_init(%s, %d, %p) failed\n", @@ -146,6 +146,7 @@ pcm_addchan(device_t dev, int dir, kobj_class_t cls, void *devinfo) PCM_UNLOCK(d); return (ENODEV); } + PCM_RELEASE(d); PCM_UNLOCK(d); return (0); @@ -388,7 +389,6 @@ pcm_init(device_t dev, void *devinfo) d->dev = dev; d->lock = snd_mtxcreate(device_get_nameunit(dev), "sound cdev"); cv_init(&d->cv, device_get_nameunit(dev)); - PCM_ACQUIRE_QUICK(d); i = 0; if (resource_int_value(device_get_name(dev), device_get_unit(dev), @@ -428,8 +428,6 @@ pcm_register(device_t dev, char *str) if (d->flags & SD_F_REGISTERED) return (EINVAL); - PCM_BUSYASSERT(d); - if (d->playcount == 0 || d->reccount == 0) d->flags |= SD_F_SIMPLEX; @@ -442,17 +440,10 @@ pcm_register(device_t dev, char *str) d->flags |= SD_F_RVCHANS; strlcpy(d->status, str, SND_STATUSLEN); - sndstat_register(dev, d->status); - - PCM_LOCK(d); /* Done, we're ready.. */ d->flags |= SD_F_REGISTERED; - PCM_RELEASE(d); - - PCM_UNLOCK(d); - /* * Create all sysctls once SD_F_REGISTERED is set else * tunable sysctls won't work: @@ -466,6 +457,8 @@ pcm_register(device_t dev, char *str) else if (snd_unit_auto == 1) snd_unit = pcm_best_unit(snd_unit); + sndstat_register(dev, d->status); + return (dsp_make_dev(dev)); }
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