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zram: Replace bit spinlocks with spinlock_t for PREEMPT_RT.

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BugLink: https://bugs.launchpad.net/bugs/2060704

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.

Use a spinlock_t on PREEMPT_RT for locking and set/ clear ZRAM_LOCK bit after
the lock has been acquired/ dropped.

Signed-off-by: Mike Galbraith <umgwanakikbuti@gmail.com>
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
Signed-off-by: Kevin Becker <kevin.becker@canonical.com>
This commit is contained in:
Mike Galbraith
2016-03-31 04:08:28 +02:00
committed by Kevin Becker
parent bc335d97f1
commit e36db925a5
2 changed files with 40 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files
drivers/block/zram/zram_drv.c
+37
View File
@@ -57,6 +57,41 @@ static void zram_free_page(struct zram *zram, size_t index);
static int zram_read_page(struct zram *zram, struct page *page, u32 index,
struct bio *parent);
#ifdef CONFIG_PREEMPT_RT
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)
{
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)
{
spin_lock(&zram->table[index].lock);
__set_bit(ZRAM_LOCK, &zram->table[index].flags);
}
static void zram_slot_unlock(struct zram *zram, u32 index)
{
__clear_bit(ZRAM_LOCK, &zram->table[index].flags);
spin_unlock(&zram->table[index].lock);
}
#else
static void zram_meta_init_table_locks(struct zram *zram, size_t num_pages) { }
static int zram_slot_trylock(struct zram *zram, u32 index)
{
return bit_spin_trylock(ZRAM_LOCK, &zram->table[index].flags);
@@ -71,6 +106,7 @@ static void zram_slot_unlock(struct zram *zram, u32 index)
{
bit_spin_unlock(ZRAM_LOCK, &zram->table[index].flags);
}
#endif
static inline bool init_done(struct zram *zram)
{
@@ -1272,6 +1308,7 @@ static bool zram_meta_alloc(struct zram *zram, u64 disksize)
if (!huge_class_size)
huge_class_size = zs_huge_class_size(zram->mem_pool);
zram_meta_init_table_locks(zram, num_pages);
return true;
}
drivers/block/zram/zram_drv.h
+3
View File
@@ -69,6 +69,9 @@ struct zram_table_entry {
unsigned long element;
};
unsigned long flags;
#ifdef CONFIG_PREEMPT_RT
spinlock_t lock;
#endif
#ifdef CONFIG_ZRAM_TRACK_ENTRY_ACTIME
ktime_t ac_time;
#endif