From: Vishal Verma <vishal.l.verma@intel.com> To: linux-nvdimm@lists.01.org Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>, Robert Moore <robert.moore@intel.com>, linux-acpi@vger.kernel.org Subject: [PATCH v4 5/6] libnvdimm: fix potential deadlock while clearing errors Date: Wed, 26 Jul 2017 17:35:45 -0600 [thread overview] Message-ID: <20170726233546.29052-6-vishal.l.verma@intel.com> (raw) In-Reply-To: <20170726233546.29052-1-vishal.l.verma@intel.com> 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> --- drivers/nvdimm/bus.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c index 937fafa..a18c291 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) -- 2.9.3 _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm
WARNING: multiple messages have this Message-ID (diff)
From: Vishal Verma <vishal.l.verma@intel.com> To: linux-nvdimm@lists.01.org Cc: linux-acpi@vger.kernel.org, Dan Williams <dan.j.williams@intel.com>, Jeff Moyer <jmoyer@redhat.com>, "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>, Toshi Kani <toshi.kani@hpe.com>, Vishal Verma <vishal.l.verma@intel.com>, Robert Moore <robert.moore@intel.com> Subject: [PATCH v4 5/6] libnvdimm: fix potential deadlock while clearing errors Date: Wed, 26 Jul 2017 17:35:45 -0600 [thread overview] Message-ID: <20170726233546.29052-6-vishal.l.verma@intel.com> (raw) In-Reply-To: <20170726233546.29052-1-vishal.l.verma@intel.com> 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> --- drivers/nvdimm/bus.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c index 937fafa..a18c291 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) -- 2.9.3
next prev parent reply other threads:[~2017-07-26 23:35 UTC|newest] Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-07-26 23:35 [PATCH v4 0/6] BTT error clearing rework Vishal Verma 2017-07-26 23:35 ` Vishal Verma 2017-07-26 23:35 ` [PATCH v4 1/6] btt: fix a missed NVDIMM_IO_ATOMIC case in the write path Vishal Verma 2017-07-26 23:35 ` Vishal Verma 2017-07-26 23:35 ` [PATCH v4 2/6] btt: refactor map entry operations with macros Vishal Verma 2017-07-26 23:35 ` Vishal Verma 2017-07-26 23:35 ` [PATCH v4 3/6] btt: ensure that flags were also unchanged during a map_read Vishal Verma 2017-07-26 23:35 ` Vishal Verma 2017-07-26 23:35 ` [PATCH v4 4/6] btt: cache sector_size in arena_info Vishal Verma 2017-07-26 23:35 ` Vishal Verma 2017-07-26 23:35 ` Vishal Verma [this message] 2017-07-26 23:35 ` [PATCH v4 5/6] libnvdimm: fix potential deadlock while clearing errors Vishal Verma 2017-07-26 23:35 ` [PATCH v4 6/6] libnvdimm, btt: rework error clearing Vishal Verma 2017-07-26 23:35 ` Vishal Verma 2017-07-31 23:15 ` [PATCH v4 0/6] BTT error clearing rework Kani, Toshimitsu 2017-07-31 23:15 ` Kani, Toshimitsu 2017-07-31 23:35 ` Verma, Vishal L 2017-07-31 23:35 ` Verma, Vishal L 2017-08-01 15:28 ` Kani, Toshimitsu 2017-08-01 15:28 ` Kani, Toshimitsu 2017-08-01 19:11 ` Kani, Toshimitsu 2017-08-01 19:11 ` Kani, Toshimitsu 2017-08-01 19:56 ` Vishal Verma 2017-08-01 19:56 ` Vishal Verma 2017-08-01 20:06 ` Kani, Toshimitsu 2017-08-01 20:06 ` Kani, Toshimitsu
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