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libnvdimm: fix potential deadlock while clearing errors

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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>
This commit is contained in:
Vishal Verma 2017-08-30 19:36:02 -06:00 committed by Dan Williams
parent 7589200450
commit 0930a750c3
1 changed files with 6 additions and 0 deletions
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6
drivers/nvdimm/bus.c
View File

@ -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)