path: root/lib
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authorLinus Torvalds <torvalds@linux-foundation.org>2011-01-10 17:11:39 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2011-01-10 17:11:39 -0800
commit5b2eef966cb2ae307aa4ef1767f7307774bc96ca (patch)
tree095a251e145903598dd8d90d5b2eb880f0d6ff93 /lib
parent8adbf8d46718a8f110de55ec82c40d04d0c362cc (diff)
parent56bec7c009872ef33fe452ea75fecba481351b44 (diff)
Merge branch 'drm-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6
* 'drm-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6: (390 commits) drm/radeon/kms: disable underscan by default drm/radeon/kms: only enable hdmi features if the monitor supports audio drm: Restore the old_fb upon modeset failure drm/nouveau: fix hwmon device binding radeon: consolidate asic-specific function decls for pre-r600 vga_switcheroo: comparing too few characters in strncmp() drm/radeon/kms: add NI pci ids drm/radeon/kms: don't enable pcie gen2 on NI yet drm/radeon/kms: add radeon_asic struct for NI asics drm/radeon/kms/ni: load default sclk/mclk/vddc at pm init drm/radeon/kms: add ucode loader for NI drm/radeon/kms: add support for DCE5 display LUTs drm/radeon/kms: add ni_reg.h drm/radeon/kms: add bo blit support for NI drm/radeon/kms: always use writeback/events for fences on NI drm/radeon/kms: adjust default clock/vddc tracking for pm on DCE5 drm/radeon/kms: add backend map workaround for barts drm/radeon/kms: fill gpu init for NI asics drm/radeon/kms: add disabled vbios accessor for NI asics drm/radeon/kms: handle NI thermal controller ...
Diffstat (limited to 'lib')
1 files changed, 30 insertions, 0 deletions
diff --git a/lib/kref.c b/lib/kref.c
index d3d227a08a4..3efb882b11d 100644
--- a/lib/kref.c
+++ b/lib/kref.c
@@ -62,6 +62,36 @@ int kref_put(struct kref *kref, void (*release)(struct kref *kref))
return 0;
+ * kref_sub - subtract a number of refcounts for object.
+ * @kref: object.
+ * @count: Number of recounts to subtract.
+ * @release: pointer to the function that will clean up the object when the
+ * last reference to the object is released.
+ * This pointer is required, and it is not acceptable to pass kfree
+ * in as this function.
+ *
+ * Subtract @count from the refcount, and if 0, call release().
+ * Return 1 if the object was removed, otherwise return 0. Beware, if this
+ * function returns 0, you still can not count on the kref from remaining in
+ * memory. Only use the return value if you want to see if the kref is now
+ * gone, not present.
+ */
+int kref_sub(struct kref *kref, unsigned int count,
+ void (*release)(struct kref *kref))
+ WARN_ON(release == NULL);
+ WARN_ON(release == (void (*)(struct kref *))kfree);
+ if (atomic_sub_and_test((int) count, &kref->refcount)) {
+ release(kref);
+ return 1;
+ }
+ return 0;