libnvdimm: fix clear poison locking with spinlock and GFP_NOWAIT allocation
The following warning results from holding a lane spinlock,
preempt_disable(), or the btt map spinlock and then trying to take the
reconfig_mutex to walk the poison list and potentially add new entries.
BUG: sleeping function called from invalid context at kernel/locking/mutex.
c:747
in_atomic(): 1, irqs_disabled(): 0, pid: 17159, name: dd
[..]
Call Trace:
dump_stack+0x85/0xc8
___might_sleep+0x184/0x250
__might_sleep+0x4a/0x90
__mutex_lock+0x58/0x9b0
? nvdimm_bus_lock+0x21/0x30 [libnvdimm]
? __nvdimm_bus_badblocks_clear+0x2f/0x60 [libnvdimm]
? acpi_nfit_forget_poison+0x79/0x80 [nfit]
? _raw_spin_unlock+0x27/0x40
mutex_lock_nested+0x1b/0x20
nvdimm_bus_lock+0x21/0x30 [libnvdimm]
nvdimm_forget_poison+0x25/0x50 [libnvdimm]
nvdimm_clear_poison+0x106/0x140 [libnvdimm]
nsio_rw_bytes+0x164/0x270 [libnvdimm]
btt_write_pg+0x1de/0x3e0 [nd_btt]
? blk_queue_enter+0x30/0x290
btt_make_request+0x11a/0x310 [nd_btt]
? blk_queue_enter+0xb7/0x290
? blk_queue_enter+0x30/0x290
generic_make_request+0x118/0x3b0
A spinlock is introduced to protect the poison list. This allows us to not
having to acquire the reconfig_mutex for touching the poison list. The
add_poison() function has been broken out into two helper functions. One to
allocate the poison entry and the other to apppend the entry. This allows us
to unlock the poison_lock in non-I/O path and continue to be able to allocate
the poison entry with GFP_KERNEL. We will use GFP_NOWAIT in the I/O path in
order to satisfy being in atomic context.
Reviewed-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
diff --git a/drivers/nvdimm/core.c b/drivers/nvdimm/core.c
index 40a3da0..2dee908 100644
--- a/drivers/nvdimm/core.c
+++ b/drivers/nvdimm/core.c
@@ -518,6 +518,15 @@ void nvdimm_badblocks_populate(struct nd_region *nd_region,
}
EXPORT_SYMBOL_GPL(nvdimm_badblocks_populate);
+static void append_poison_entry(struct nvdimm_bus *nvdimm_bus,
+ struct nd_poison *pl, u64 addr, u64 length)
+{
+ lockdep_assert_held(&nvdimm_bus->poison_lock);
+ pl->start = addr;
+ pl->length = length;
+ list_add_tail(&pl->list, &nvdimm_bus->poison_list);
+}
+
static int add_poison(struct nvdimm_bus *nvdimm_bus, u64 addr, u64 length,
gfp_t flags)
{
@@ -527,19 +536,24 @@ static int add_poison(struct nvdimm_bus *nvdimm_bus, u64 addr, u64 length,
if (!pl)
return -ENOMEM;
- pl->start = addr;
- pl->length = length;
- list_add_tail(&pl->list, &nvdimm_bus->poison_list);
-
+ append_poison_entry(nvdimm_bus, pl, addr, length);
return 0;
}
static int bus_add_poison(struct nvdimm_bus *nvdimm_bus, u64 addr, u64 length)
{
- struct nd_poison *pl;
+ struct nd_poison *pl, *pl_new;
- if (list_empty(&nvdimm_bus->poison_list))
- return add_poison(nvdimm_bus, addr, length, GFP_KERNEL);
+ spin_unlock(&nvdimm_bus->poison_lock);
+ pl_new = kzalloc(sizeof(*pl_new), GFP_KERNEL);
+ spin_lock(&nvdimm_bus->poison_lock);
+
+ if (list_empty(&nvdimm_bus->poison_list)) {
+ if (!pl_new)
+ return -ENOMEM;
+ append_poison_entry(nvdimm_bus, pl_new, addr, length);
+ return 0;
+ }
/*
* There is a chance this is a duplicate, check for those first.
@@ -551,6 +565,7 @@ static int bus_add_poison(struct nvdimm_bus *nvdimm_bus, u64 addr, u64 length)
/* If length has changed, update this list entry */
if (pl->length != length)
pl->length = length;
+ kfree(pl_new);
return 0;
}
@@ -559,30 +574,33 @@ static int bus_add_poison(struct nvdimm_bus *nvdimm_bus, u64 addr, u64 length)
* as any overlapping ranges will get resolved when the list is consumed
* and converted to badblocks
*/
- return add_poison(nvdimm_bus, addr, length, GFP_KERNEL);
+ if (!pl_new)
+ return -ENOMEM;
+ append_poison_entry(nvdimm_bus, pl_new, addr, length);
+
+ return 0;
}
int nvdimm_bus_add_poison(struct nvdimm_bus *nvdimm_bus, u64 addr, u64 length)
{
int rc;
- nvdimm_bus_lock(&nvdimm_bus->dev);
+ spin_lock(&nvdimm_bus->poison_lock);
rc = bus_add_poison(nvdimm_bus, addr, length);
- nvdimm_bus_unlock(&nvdimm_bus->dev);
+ spin_unlock(&nvdimm_bus->poison_lock);
return rc;
}
EXPORT_SYMBOL_GPL(nvdimm_bus_add_poison);
-void __nvdimm_forget_poison(struct nvdimm_bus *nvdimm_bus, phys_addr_t start,
+void nvdimm_forget_poison(struct nvdimm_bus *nvdimm_bus, phys_addr_t start,
unsigned int len)
{
struct list_head *poison_list = &nvdimm_bus->poison_list;
u64 clr_end = start + len - 1;
struct nd_poison *pl, *next;
- lockdep_assert_held(&nvdimm_bus->reconfig_mutex);
-
+ spin_lock(&nvdimm_bus->poison_lock);
WARN_ON_ONCE(list_empty(poison_list));
/*
@@ -629,21 +647,13 @@ void __nvdimm_forget_poison(struct nvdimm_bus *nvdimm_bus, phys_addr_t start,
u64 new_len = pl_end - new_start + 1;
/* Add new entry covering the right half */
- add_poison(nvdimm_bus, new_start, new_len, GFP_NOIO);
+ add_poison(nvdimm_bus, new_start, new_len, GFP_NOWAIT);
/* Adjust this entry to cover the left half */
pl->length = start - pl->start;
continue;
}
}
-}
-EXPORT_SYMBOL_GPL(__nvdimm_forget_poison);
-
-void nvdimm_forget_poison(struct nvdimm_bus *nvdimm_bus,
- phys_addr_t start, unsigned int len)
-{
- nvdimm_bus_lock(&nvdimm_bus->dev);
- __nvdimm_forget_poison(nvdimm_bus, start, len);
- nvdimm_bus_unlock(&nvdimm_bus->dev);
+ spin_unlock(&nvdimm_bus->poison_lock);
}
EXPORT_SYMBOL_GPL(nvdimm_forget_poison);