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From: Vishal Verma <vishal.l.verma@intel.com>
To: linux-nvdimm@lists.01.org
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
	linux-acpi@vger.kernel.org
Subject: [PATCH 2/3] pmem: reduce kmap_atomic sections to the memcpys only
Date: Fri, 30 Sep 2016 17:19:30 -0600	[thread overview]
Message-ID: <1475277571-10152-3-git-send-email-vishal.l.verma@intel.com> (raw)
In-Reply-To: <1475277571-10152-1-git-send-email-vishal.l.verma@intel.com>

pmem_do_bvec used to kmap_atomic at the begin, and only unmap at the
end. Things like nvdimm_clear_poison may want to do nvdimm subsystem
bookkeeping operations that may involve taking locks or doing memory
allocations, and we can't do that from the atomic context. Reduce the
atomic context to just what needs it - the memcpy to/from pmem.

Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
---
 drivers/nvdimm/pmem.c | 28 +++++++++++++++++++++++-----
 1 file changed, 23 insertions(+), 5 deletions(-)

diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 571a6c7..42b3a82 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -66,13 +66,32 @@ static void pmem_clear_poison(struct pmem_device *pmem, phys_addr_t offset,
 	invalidate_pmem(pmem->virt_addr + offset, len);
 }
 
+static void write_pmem(void *pmem_addr, struct page *page,
+		unsigned int off, unsigned int len)
+{
+	void *mem = kmap_atomic(page);
+
+	memcpy_to_pmem(pmem_addr, mem + off, len);
+	kunmap_atomic(mem);
+}
+
+static int read_pmem(struct page *page, unsigned int off,
+		void *pmem_addr, unsigned int len)
+{
+	int rc;
+	void *mem = kmap_atomic(page);
+
+	rc = memcpy_from_pmem(mem + off, pmem_addr, len);
+	kunmap_atomic(mem);
+	return rc;
+}
+
 static int pmem_do_bvec(struct pmem_device *pmem, struct page *page,
 			unsigned int len, unsigned int off, bool is_write,
 			sector_t sector)
 {
 	int rc = 0;
 	bool bad_pmem = false;
-	void *mem = kmap_atomic(page);
 	phys_addr_t pmem_off = sector * 512 + pmem->data_offset;
 	void *pmem_addr = pmem->virt_addr + pmem_off;
 
@@ -83,7 +102,7 @@ static int pmem_do_bvec(struct pmem_device *pmem, struct page *page,
 		if (unlikely(bad_pmem))
 			rc = -EIO;
 		else {
-			rc = memcpy_from_pmem(mem + off, pmem_addr, len);
+			rc = read_pmem(page, off, pmem_addr, len);
 			flush_dcache_page(page);
 		}
 	} else {
@@ -102,14 +121,13 @@ static int pmem_do_bvec(struct pmem_device *pmem, struct page *page,
 		 * after clear poison.
 		 */
 		flush_dcache_page(page);
-		memcpy_to_pmem(pmem_addr, mem + off, len);
+		write_pmem(pmem_addr, page, off, len);
 		if (unlikely(bad_pmem)) {
 			pmem_clear_poison(pmem, pmem_off, len);
-			memcpy_to_pmem(pmem_addr, mem + off, len);
+			write_pmem(pmem_addr, page, off, len);
 		}
 	}
 
-	kunmap_atomic(mem);
 	return rc;
 }
 
-- 
2.7.4

_______________________________________________
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: Dan Williams <dan.j.williams@intel.com>,
	Ross Zwisler <ross.zwisler@linux.intel.com>,
	Linda Knippers <linda.knippers@hpe.com>,
	linux-acpi@vger.kernel.org,
	"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
	Vishal Verma <vishal.l.verma@intel.com>
Subject: [PATCH 2/3] pmem: reduce kmap_atomic sections to the memcpys only
Date: Fri, 30 Sep 2016 17:19:30 -0600	[thread overview]
Message-ID: <1475277571-10152-3-git-send-email-vishal.l.verma@intel.com> (raw)
In-Reply-To: <1475277571-10152-1-git-send-email-vishal.l.verma@intel.com>

pmem_do_bvec used to kmap_atomic at the begin, and only unmap at the
end. Things like nvdimm_clear_poison may want to do nvdimm subsystem
bookkeeping operations that may involve taking locks or doing memory
allocations, and we can't do that from the atomic context. Reduce the
atomic context to just what needs it - the memcpy to/from pmem.

Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
---
 drivers/nvdimm/pmem.c | 28 +++++++++++++++++++++++-----
 1 file changed, 23 insertions(+), 5 deletions(-)

diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 571a6c7..42b3a82 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -66,13 +66,32 @@ static void pmem_clear_poison(struct pmem_device *pmem, phys_addr_t offset,
 	invalidate_pmem(pmem->virt_addr + offset, len);
 }
 
+static void write_pmem(void *pmem_addr, struct page *page,
+		unsigned int off, unsigned int len)
+{
+	void *mem = kmap_atomic(page);
+
+	memcpy_to_pmem(pmem_addr, mem + off, len);
+	kunmap_atomic(mem);
+}
+
+static int read_pmem(struct page *page, unsigned int off,
+		void *pmem_addr, unsigned int len)
+{
+	int rc;
+	void *mem = kmap_atomic(page);
+
+	rc = memcpy_from_pmem(mem + off, pmem_addr, len);
+	kunmap_atomic(mem);
+	return rc;
+}
+
 static int pmem_do_bvec(struct pmem_device *pmem, struct page *page,
 			unsigned int len, unsigned int off, bool is_write,
 			sector_t sector)
 {
 	int rc = 0;
 	bool bad_pmem = false;
-	void *mem = kmap_atomic(page);
 	phys_addr_t pmem_off = sector * 512 + pmem->data_offset;
 	void *pmem_addr = pmem->virt_addr + pmem_off;
 
@@ -83,7 +102,7 @@ static int pmem_do_bvec(struct pmem_device *pmem, struct page *page,
 		if (unlikely(bad_pmem))
 			rc = -EIO;
 		else {
-			rc = memcpy_from_pmem(mem + off, pmem_addr, len);
+			rc = read_pmem(page, off, pmem_addr, len);
 			flush_dcache_page(page);
 		}
 	} else {
@@ -102,14 +121,13 @@ static int pmem_do_bvec(struct pmem_device *pmem, struct page *page,
 		 * after clear poison.
 		 */
 		flush_dcache_page(page);
-		memcpy_to_pmem(pmem_addr, mem + off, len);
+		write_pmem(pmem_addr, page, off, len);
 		if (unlikely(bad_pmem)) {
 			pmem_clear_poison(pmem, pmem_off, len);
-			memcpy_to_pmem(pmem_addr, mem + off, len);
+			write_pmem(pmem_addr, page, off, len);
 		}
 	}
 
-	kunmap_atomic(mem);
 	return rc;
 }
 
-- 
2.7.4


  parent reply	other threads:[~2016-09-30 23:20 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-30 23:19 [PATCH 0/3] misc updates for Address Range Scrub Vishal Verma
2016-09-30 23:19 ` Vishal Verma
2016-09-30 23:19 ` [PATCH 1/3] nfit: don't start a full scrub by default for an MCE Vishal Verma
2016-09-30 23:19   ` Vishal Verma
2016-09-30 23:19 ` Vishal Verma [this message]
2016-09-30 23:19   ` [PATCH 2/3] pmem: reduce kmap_atomic sections to the memcpys only Vishal Verma
2016-09-30 23:19 ` [PATCH 3/3] libnvdimm: clear the internal poison_list when clearing badblocks Vishal Verma
2016-09-30 23:19   ` Vishal Verma
  -- strict thread matches above, loose matches on Subject: below --
2016-09-29  0:10 [PATCH 0/3] misc updates for Address Range Scrub Vishal Verma
2016-09-29  0:10 ` [PATCH 2/3] pmem: reduce kmap_atomic sections to the memcpys only Vishal Verma
2016-09-29  0:10   ` Vishal Verma

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