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authorVishal Verma <vishal.l.verma@intel.com>2017-08-30 19:36:02 -0600
committerDan Williams <dan.j.williams@intel.com>2017-08-31 15:05:10 -0700
commit0930a750c35be3c2f5aacebc0d20ddeaf727c208 (patch)
tree9fdf04c2bea121e8d9405e816d1cadfef4389b8c /drivers/nvdimm
parent75892004508260df72ed3d319f10d2acd516220e (diff)
downloadlinux-0930a750c35be3c2f5aacebc0d20ddeaf727c208.tar.bz2
libnvdimm: fix potential deadlock while clearing errors
With the ACPI NFIT 'DSM' methods, acpi can be called from IO paths. Specifically, the DSM to clear media errors is called during writes, so that we can provide a writes-fix-errors model. However it is easy to imagine a scenario like: -> write through the nvdimm driver -> acpi allocation -> writeback, causes more IO through the nvdimm driver -> deadlock Fix this by using memalloc_noio_{save,restore}, which sets the GFP_NOIO flag for the current scope when issuing commands/IOs that are expected to clear errors. Cc: <linux-acpi@vger.kernel.org> Cc: <linux-nvdimm@lists.01.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Robert Moore <robert.moore@intel.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Vishal Verma <vishal.l.verma@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'drivers/nvdimm')
-rw-r--r--drivers/nvdimm/bus.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c
index 937fafa1886a..a18c2914f4b6 100644
--- a/drivers/nvdimm/bus.c
+++ b/drivers/nvdimm/bus.c
@@ -11,6 +11,7 @@
* General Public License for more details.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/sched/mm.h>
#include <linux/vmalloc.h>
#include <linux/uaccess.h>
#include <linux/module.h>
@@ -234,6 +235,7 @@ long nvdimm_clear_poison(struct device *dev, phys_addr_t phys,
struct nd_cmd_clear_error clear_err;
struct nd_cmd_ars_cap ars_cap;
u32 clear_err_unit, mask;
+ unsigned int noio_flag;
int cmd_rc, rc;
if (!nvdimm_bus)
@@ -250,8 +252,10 @@ long nvdimm_clear_poison(struct device *dev, phys_addr_t phys,
memset(&ars_cap, 0, sizeof(ars_cap));
ars_cap.address = phys;
ars_cap.length = len;
+ noio_flag = memalloc_noio_save();
rc = nd_desc->ndctl(nd_desc, NULL, ND_CMD_ARS_CAP, &ars_cap,
sizeof(ars_cap), &cmd_rc);
+ memalloc_noio_restore(noio_flag);
if (rc < 0)
return rc;
if (cmd_rc < 0)
@@ -266,8 +270,10 @@ long nvdimm_clear_poison(struct device *dev, phys_addr_t phys,
memset(&clear_err, 0, sizeof(clear_err));
clear_err.address = phys;
clear_err.length = len;
+ noio_flag = memalloc_noio_save();
rc = nd_desc->ndctl(nd_desc, NULL, ND_CMD_CLEAR_ERROR, &clear_err,
sizeof(clear_err), &cmd_rc);
+ memalloc_noio_restore(noio_flag);
if (rc < 0)
return rc;
if (cmd_rc < 0)