1 files changed, 84 insertions, 0 deletions
diff --git a/debian/patches-rt/0001-zram-Replace-bit-spinlocks-with-a-spinlock_t.patch b/debian/patches-rt/0001-zram-Replace-bit-spinlocks-with-a-spinlock_t.patch
new file mode 100644
index 0000000000..81f4f3c5dd
--- /dev/null
+++ b/debian/patches-rt/0001-zram-Replace-bit-spinlocks-with-a-spinlock_t.patch
@@ -0,0 +1,84 @@
+From: Mike Galbraith <umgwanakikbuti@gmail.com>
+Date: Thu, 31 Mar 2016 04:08:28 +0200
+Subject: [PATCH 1/3] zram: Replace bit spinlocks with a spinlock_t.
+Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.10/older/patches-6.10.2-rt14.tar.xz
+
+The bit spinlock disables preemption. The spinlock_t lock becomes a sleeping
+lock on PREEMPT_RT and it can not be acquired in this context. In this locked
+section, zs_free() acquires a zs_pool::lock, and there is access to
+zram::wb_limit_lock.
+
+Add a spinlock_t for locking. Keep the set/ clear ZRAM_LOCK bit after
+the lock has been acquired/ dropped. The size of struct zram_table_entry
+increases by 4 bytes due to lock and additional 4 bytes padding with
+CONFIG_ZRAM_TRACK_ENTRY_ACTIME enabled.
+
+Signed-off-by: Mike Galbraith <umgwanakikbuti@gmail.com>
+Link: https://lore.kernel.org/r/20240620153556.777272-2-bigeasy@linutronix.de
+Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
+Link: https://lkml.kernel.org/r/YqIbMuHCPiQk+Ac2@linutronix.de
+Link: https://lore.kernel.org/20230323161830.jFbWCosd@linutronix.de
+Link: https://lore.kernel.org/20240619150814.BRAvaziM@linutronix.de
+---
+ drivers/block/zram/zram_drv.c |   22 +++++++++++++++++++---
+ drivers/block/zram/zram_drv.h |    1 +
+ 2 files changed, 20 insertions(+), 3 deletions(-)
+
+--- a/drivers/block/zram/zram_drv.c
++++ b/drivers/block/zram/zram_drv.c
+@@ -57,19 +57,34 @@ static void zram_free_page(struct zram *
+ static int zram_read_page(struct zram *zram, struct page *page, u32 index,
+ 			  struct bio *parent);
+ 
++static void zram_meta_init_table_locks(struct zram *zram, size_t num_pages)
++{
++	size_t index;
++
++	for (index = 0; index < num_pages; index++)
++		spin_lock_init(&zram->table[index].lock);
++}
++
+ static int zram_slot_trylock(struct zram *zram, u32 index)
+ {
+-	return bit_spin_trylock(ZRAM_LOCK, &zram->table[index].flags);
++	int ret;
++
++	ret = spin_trylock(&zram->table[index].lock);
++	if (ret)
++		__set_bit(ZRAM_LOCK, &zram->table[index].flags);
++	return ret;
+ }
+ 
+ static void zram_slot_lock(struct zram *zram, u32 index)
+ {
+-	bit_spin_lock(ZRAM_LOCK, &zram->table[index].flags);
++	spin_lock(&zram->table[index].lock);
++	__set_bit(ZRAM_LOCK, &zram->table[index].flags);
+ }
+ 
+ static void zram_slot_unlock(struct zram *zram, u32 index)
+ {
+-	bit_spin_unlock(ZRAM_LOCK, &zram->table[index].flags);
++	__clear_bit(ZRAM_LOCK, &zram->table[index].flags);
++	spin_unlock(&zram->table[index].lock);
+ }
+ 
+ static inline bool init_done(struct zram *zram)
+@@ -1226,6 +1241,7 @@ static bool zram_meta_alloc(struct zram
+ 
+ 	if (!huge_class_size)
+ 		huge_class_size = zs_huge_class_size(zram->mem_pool);
++	zram_meta_init_table_locks(zram, num_pages);
+ 	return true;
+ }
+ 
+--- a/drivers/block/zram/zram_drv.h
++++ b/drivers/block/zram/zram_drv.h
+@@ -69,6 +69,7 @@ struct zram_table_entry {
+ 		unsigned long element;
+ 	};
+ 	unsigned long flags;
++	spinlock_t lock;
+ #ifdef CONFIG_ZRAM_TRACK_ENTRY_ACTIME
+ 	ktime_t ac_time;
+ #endif