Date: Tue, 6 Apr 2021 00:38:53 GMT From: Konstantin Belousov <kib@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: f6b108837e7d - main - linuxkpi: avoid counting per-thread use for the embedded linux cdevs Message-ID: <202104060038.1360cr9Z029505@gitrepo.freebsd.org>
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The branch main has been updated by kib: URL: https://cgit.FreeBSD.org/src/commit/?id=f6b108837e7df7d7bfb35ec447f7cb62afa79441 commit f6b108837e7df7d7bfb35ec447f7cb62afa79441 Author: Konstantin Belousov <kib@FreeBSD.org> AuthorDate: 2021-03-30 08:45:24 +0000 Commit: Konstantin Belousov <kib@FreeBSD.org> CommitDate: 2021-04-06 00:38:29 +0000 linuxkpi: avoid counting per-thread use for the embedded linux cdevs The counter is not used to control destroy. Reviewed by: hselasky Sponsored by: Mellanox Technologies/NVidia Networking MFC after: 1 week --- sys/compat/linuxkpi/common/src/linux_compat.c | 31 ++++++++++++++-------- sys/compat/linuxkpi/common/src/linux_compat.c.orig | 13 ++++++--- 2 files changed, 30 insertions(+), 14 deletions(-) diff --git a/sys/compat/linuxkpi/common/src/linux_compat.c b/sys/compat/linuxkpi/common/src/linux_compat.c index 71ea7e0844dc..28413c59bb76 100644 --- a/sys/compat/linuxkpi/common/src/linux_compat.c +++ b/sys/compat/linuxkpi/common/src/linux_compat.c @@ -717,15 +717,19 @@ linux_get_fop(struct linux_file *filp, const struct file_operations **fop, ldev = filp->f_cdev; *fop = filp->f_op; if (ldev != NULL) { - for (siref = ldev->siref;;) { - if ((siref & LDEV_SI_DTR) != 0) { - ldev = &dummy_ldev; - siref = ldev->siref; - *fop = ldev->ops; - MPASS((ldev->siref & LDEV_SI_DTR) == 0); - } else if (atomic_fcmpset_int(&ldev->siref, &siref, - siref + LDEV_SI_REF)) { - break; + if (ldev->kobj.ktype == &linux_cdev_static_ktype) { + refcount_acquire(&ldev->refs); + } else { + for (siref = ldev->siref;;) { + if ((siref & LDEV_SI_DTR) != 0) { + ldev = &dummy_ldev; + *fop = ldev->ops; + siref = ldev->siref; + MPASS((ldev->siref & LDEV_SI_DTR) == 0); + } else if (atomic_fcmpset_int(&ldev->siref, + &siref, siref + LDEV_SI_REF)) { + break; + } } } } @@ -738,8 +742,13 @@ linux_drop_fop(struct linux_cdev *ldev) if (ldev == NULL) return; - MPASS((ldev->siref & ~LDEV_SI_DTR) != 0); - atomic_subtract_int(&ldev->siref, LDEV_SI_REF); + if (ldev->kobj.ktype == &linux_cdev_static_ktype) { + linux_cdev_deref(ldev); + } else { + MPASS(ldev->kobj.ktype == &linux_cdev_ktype); + MPASS((ldev->siref & ~LDEV_SI_DTR) != 0); + atomic_subtract_int(&ldev->siref, LDEV_SI_REF); + } } #define OPW(fp,td,code) ({ \ diff --git a/sys/compat/linuxkpi/common/src/linux_compat.c.orig b/sys/compat/linuxkpi/common/src/linux_compat.c.orig index 0731859e7a53..71ea7e0844dc 100644 --- a/sys/compat/linuxkpi/common/src/linux_compat.c.orig +++ b/sys/compat/linuxkpi/common/src/linux_compat.c.orig @@ -2199,8 +2199,8 @@ linux_completion_done(struct completion *c) static void linux_cdev_deref(struct linux_cdev *ldev) { - - if (refcount_release(&ldev->refs)) + if (refcount_release(&ldev->refs) && + ldev->kobj.ktype == &linux_cdev_ktype) kfree(ldev); } @@ -2220,12 +2220,17 @@ linux_cdev_release(struct kobject *kobj) static void linux_cdev_static_release(struct kobject *kobj) { + struct cdev *cdev; struct linux_cdev *ldev; struct kobject *parent; ldev = container_of(kobj, struct linux_cdev, kobj); parent = kobj->parent; - linux_destroy_dev(ldev); + cdev = ldev->cdev; + if (cdev != NULL) { + destroy_dev(cdev); + ldev->cdev = NULL; + } kobject_put(parent); } @@ -2237,6 +2242,8 @@ linux_destroy_dev(struct linux_cdev *ldev) return; MPASS((ldev->siref & LDEV_SI_DTR) == 0); + MPASS(ldev->kobj.ktype == &linux_cdev_ktype); + atomic_set_int(&ldev->siref, LDEV_SI_DTR); while ((atomic_load_int(&ldev->siref) & ~LDEV_SI_DTR) != 0) pause("ldevdtr", hz / 4);
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