From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergey Senozhatsky Subject: Re: [PATCH 2/2] i915: do not leak module ref counter Date: Fri, 2 Aug 2019 22:49:55 +0900 Message-ID: <20190802134955.GA23032@tigerII.localdomain> References: <20190802123956.2450-1-sergey.senozhatsky@gmail.com> <20190802123956.2450-2-sergey.senozhatsky@gmail.com> <156475071634.6598.8668583907388398632@skylake-alporthouse-com> <156475141863.6598.6809215010139776043@skylake-alporthouse-com> <20190802131523.GB466@tigerII.localdomain> <20190802133503.GA18318@tigerII.localdomain> <156475327511.6598.417403815598052974@skylake-alporthouse-com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <156475327511.6598.417403815598052974@skylake-alporthouse-com> Sender: linux-kernel-owner@vger.kernel.org To: Chris Wilson Cc: Sergey Senozhatsky , Jani Nikula , Joonas Lahtinen , Rodrigo Vivi , David Airlie , Daniel Vetter , intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org List-Id: intel-gfx@lists.freedesktop.org On (08/02/19 14:41), Chris Wilson wrote: [..] > struct vfsmount *kern_mount(struct file_system_type *type) > { > struct vfsmount *mnt; > mnt = vfs_kern_mount(type, SB_KERNMOUNT, type->name, NULL); > if (!IS_ERR(mnt)) { > /* > * it is a longterm mount, don't release mnt until > * we unmount before file sys is unregistered > */ > real_mount(mnt)->mnt_ns = MNT_NS_INTERNAL; > } > return mnt; > } > > With the exception of fiddling with MNT_NS_INTERNAL, it seems > amenable for our needs. Sorry, not sure I understand. i915 use kern_mount() at the moment. Since we still need to put_filesystem(), I'd probably add one more patch - export put_filesystem() so then we can put_filesystem() in i915. Wonder what would happen if someone would do modprobe i915 rmmod i916 In a loop. So something like this (this is against current patch set). --- drivers/gpu/drm/i915/gem/i915_gemfs.c | 5 ++--- fs/filesystems.c | 2 +- 2 files changed, 3 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/i915/gem/i915_gemfs.c b/drivers/gpu/drm/i915/gem/i915_gemfs.c index d437188d1736..4ea7a6f750f4 100644 --- a/drivers/gpu/drm/i915/gem/i915_gemfs.c +++ b/drivers/gpu/drm/i915/gem/i915_gemfs.c @@ -24,10 +24,9 @@ int i915_gemfs_init(struct drm_i915_private *i915) return -ENODEV; gemfs = kern_mount(type); - if (IS_ERR(gemfs)) { - put_filesystem(type); + put_filesystem(type); + if (IS_ERR(gemfs)) return PTR_ERR(gemfs); - } /* * Enable huge-pages for objects that are at least HPAGE_PMD_SIZE, most diff --git a/fs/filesystems.c b/fs/filesystems.c index 9135646e41ac..4837eda748b5 100644 --- a/fs/filesystems.c +++ b/fs/filesystems.c @@ -45,6 +45,7 @@ void put_filesystem(struct file_system_type *fs) { module_put(fs->owner); } +EXPORT_SYMBOL(put_filesystem); static struct file_system_type **find_filesystem(const char *name, unsigned len) { @@ -280,5 +281,4 @@ struct file_system_type *get_fs_type(const char *name) } return fs; } - EXPORT_SYMBOL(get_fs_type);