From f4cdf7ca9a1fdcca413157df19753f388a5a224e Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Wed, 19 Aug 2026 10:09:22 -0700 Subject: Merge tag 'media/v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media Pull media updates from Mauro Carvalho Chehab: - v4l2-core: added ISP statistics support and per-block validation - v4l2-core: Allow unknown HDR10 white point and luminance - New camera sensors: Sony IMX678 and IMX471m, Himax HM1092 IR sensor - New codec: Milos: VPU v2.0 codec support - isp driver: gained support for Dreamchip RPPX1 ISP framework - vsp1 driver: gained support for RZ/T2H and RZ/N2H - Novalake driver: gained CVS support for new NVL hardware - dvb-core: fix feed leak on failed DMX_ADD_PID - several driver fixes, cleanups and minor improvements * tag 'media/v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (308 commits) media: ipu-bridge: check all DMI entries when overriding sensor rotation media: v4l2-async: avoid deleting unlinked ASC entry on link error media: rzg2l-cru: Align bytesperline to hardware DMA stride requirement media: intel/ipu6: fix async notifier cleanup leak on parse error media: staging/ipu7: fix async notifier UAF on probe error path media: amd: isp4: fix self-deadlock in isp4sd_pwron_and_init() error path media: amd: isp4: release partial allocations in isp4if_alloc_fw_gpumem() media: rcar-isp: Fix VSPX reference leaks media: rcar-isp: Release ISPCORE resources media: i2c: imx415: Release runtime PM reference on VBLANK error media: i2c: imx415: Return test pattern write errors media: renesas: vsp1: Declare index variables in for loop statement media: renesas: vsp1: Make reset control optional to support platforms without a reset line media: dt-bindings: media: renesas,vsp1: Document RZ/T2H and RZ/N2H SoCs media: dt-bindings: media: renesas,fcp: Document RZ/T2H and RZ/N2H SoCs media: nxp: imx8-isi: Add additional 32-bit RGB format support media: nxp: imx8-isi: Add 16-bit raw Bayer format support media: nxp: imx8-isi: Implement per-stream reference counting for multiplexed streams media: nxp: imx8-isi: Use BIT_ULL() for 64-bit stream masks media: nxp: imx8-isi: Correct color map between V4L2 and ISI ... --- lib/lockref.c | 163 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 163 insertions(+) create mode 100644 lib/lockref.c (limited to 'lib/lockref.c') diff --git a/lib/lockref.c b/lib/lockref.c new file mode 100644 index 000000000..9b3dd688d --- /dev/null +++ b/lib/lockref.c @@ -0,0 +1,163 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include + +#if USE_CMPXCHG_LOCKREF + +/* + * Note that the "cmpxchg()" reloads the "old" value for the + * failure case. + */ +#define CMPXCHG_LOOP(CODE, SUCCESS) do { \ + int retry = 100; \ + struct lockref old; \ + BUILD_BUG_ON(sizeof(old) != 8); \ + old.lock_count = READ_ONCE(lockref->lock_count); \ + while (likely(arch_spin_value_unlocked(old.lock.rlock.raw_lock))) { \ + struct lockref new = old; \ + CODE \ + if (likely(try_cmpxchg64_relaxed(&lockref->lock_count, \ + &old.lock_count, \ + new.lock_count))) { \ + SUCCESS; \ + } \ + if (!--retry) \ + break; \ + } \ +} while (0) + +#else + +#define CMPXCHG_LOOP(CODE, SUCCESS) do { } while (0) + +#endif + +/** + * lockref_get - Increments reference count unconditionally + * @lockref: pointer to lockref structure + * + * This operation is only valid if you already hold a reference + * to the object, so you know the count cannot be zero. + */ +void lockref_get(struct lockref *lockref) +{ + CMPXCHG_LOOP( + new.count++; + , + return; + ); + + spin_lock(&lockref->lock); + lockref->count++; + spin_unlock(&lockref->lock); +} +EXPORT_SYMBOL(lockref_get); + +/** + * lockref_get_not_zero - Increments count unless the count is 0 or dead + * @lockref: pointer to lockref structure + * Return: 1 if count updated successfully or 0 if count was zero + */ +bool lockref_get_not_zero(struct lockref *lockref) +{ + bool retval = false; + + CMPXCHG_LOOP( + new.count++; + if (old.count <= 0) + return false; + , + return true; + ); + + spin_lock(&lockref->lock); + if (lockref->count > 0) { + lockref->count++; + retval = true; + } + spin_unlock(&lockref->lock); + return retval; +} +EXPORT_SYMBOL(lockref_get_not_zero); + +/** + * lockref_put_return - Decrement reference count if possible + * @lockref: pointer to lockref structure + * + * Decrement the reference count and return the new value. + * If the lockref was dead or locked, return -1. + */ +int lockref_put_return(struct lockref *lockref) +{ + CMPXCHG_LOOP( + new.count--; + if (old.count <= 0) + return -1; + , + return new.count; + ); + return -1; +} +EXPORT_SYMBOL(lockref_put_return); + +/** + * lockref_put_or_lock - decrements count unless count <= 1 before decrement + * @lockref: pointer to lockref structure + * Return: 1 if count updated successfully or 0 if count <= 1 and lock taken + */ +bool lockref_put_or_lock(struct lockref *lockref) +{ + CMPXCHG_LOOP( + new.count--; + if (old.count <= 1) + break; + , + return true; + ); + + spin_lock(&lockref->lock); + if (lockref->count <= 1) + return false; + lockref->count--; + spin_unlock(&lockref->lock); + return true; +} +EXPORT_SYMBOL(lockref_put_or_lock); + +/** + * lockref_mark_dead - mark lockref dead + * @lockref: pointer to lockref structure + */ +void lockref_mark_dead(struct lockref *lockref) +{ + assert_spin_locked(&lockref->lock); + lockref->count = __LOCKREF_DEAD_VAL; +} +EXPORT_SYMBOL(lockref_mark_dead); + +/** + * lockref_get_not_dead - Increments count unless the ref is dead + * @lockref: pointer to lockref structure + * Return: 1 if count updated successfully or 0 if lockref was dead + */ +bool lockref_get_not_dead(struct lockref *lockref) +{ + bool retval = false; + + CMPXCHG_LOOP( + new.count++; + if (old.count < 0) + return false; + , + return true; + ); + + spin_lock(&lockref->lock); + if (lockref->count >= 0) { + lockref->count++; + retval = true; + } + spin_unlock(&lockref->lock); + return retval; +} +EXPORT_SYMBOL(lockref_get_not_dead); -- cgit v1.3.1