target/rd: Refactor rd_build_device_space + rd_release_device_space

This patch refactors rd_build_device_space() + rd_release_device_space()
into rd_allocate_sgl_table() + rd_release_device_space() so that they
may be used seperatly for setup + release of protection information
scatterlists.

Also add explicit memset of pages within rd_allocate_sgl_table() based
upon passed 'init_payload' value.

v2 changes:
  - Drop unused sg_table from rd_release_device_space (Wei)

Cc: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 68 insertions, 45 deletions

diff --git a/drivers/target/target_core_rd.c b/drivers/target/target_core_rd.c
index 4ffe5f2ec0e9..e9fa879ac27f 100644
--- a/drivers/target/target_core_rd.c
+++ b/drivers/target/target_core_rd.c
@@ -78,23 +78,14 @@ static void rd_detach_hba(struct se_hba *hba)
         hba->hba_ptr = NULL;
 }
 
-/*      rd_release_device_space():
- *
- *
- */
-static void rd_release_device_space(struct rd_dev *rd_dev)
+static u32 rd_release_sgl_table(struct rd_dev *rd_dev, struct rd_dev_sg_table *sg_table,
+                                 u32 sg_table_count)
 {
-        u32 i, j, page_count = 0, sg_per_table;
-        struct rd_dev_sg_table *sg_table;
         struct page *pg;
         struct scatterlist *sg;
+        u32 i, j, page_count = 0, sg_per_table;
 
-        if (!rd_dev->sg_table_array || !rd_dev->sg_table_count)
-                return;
-
-        sg_table = rd_dev->sg_table_array;
-
-        for (i = 0; i < rd_dev->sg_table_count; i++) {
+        for (i = 0; i < sg_table_count; i++) {
                 sg = sg_table[i].sg_table;
                 sg_per_table = sg_table[i].rd_sg_count;
 
@@ -105,16 +96,28 @@ static void rd_release_device_space(struct rd_dev *rd_dev)
                                 page_count++;
                         }
                 }
-
                 kfree(sg);
         }
 
+        kfree(sg_table);
+        return page_count;
+}
+
+static void rd_release_device_space(struct rd_dev *rd_dev)
+{
+        u32 page_count;
+
+        if (!rd_dev->sg_table_array || !rd_dev->sg_table_count)
+                return;
+
+        page_count = rd_release_sgl_table(rd_dev, rd_dev->sg_table_array,
+                                          rd_dev->sg_table_count);
+
         pr_debug("CORE_RD[%u] - Released device space for Ramdisk"
                 " Device ID: %u, pages %u in %u tables total bytes %lu\n",
                 rd_dev->rd_host->rd_host_id, rd_dev->rd_dev_id, page_count,
                 rd_dev->sg_table_count, (unsigned long)page_count * PAGE_SIZE);
 
-        kfree(sg_table);
         rd_dev->sg_table_array = NULL;
         rd_dev->sg_table_count = 0;
 }
@@ -124,38 +127,15 @@ static void rd_release_device_space(struct rd_dev *rd_dev)
  *
  *
  */
-static int rd_build_device_space(struct rd_dev *rd_dev)
+static int rd_allocate_sgl_table(struct rd_dev *rd_dev, struct rd_dev_sg_table *sg_table,
+                                 u32 total_sg_needed, unsigned char init_payload)
 {
-        u32 i = 0, j, page_offset = 0, sg_per_table, sg_tables, total_sg_needed;
+        u32 i = 0, j, page_offset = 0, sg_per_table;
         u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE /
                                 sizeof(struct scatterlist));
-        struct rd_dev_sg_table *sg_table;
         struct page *pg;
         struct scatterlist *sg;
-
-        if (rd_dev->rd_page_count <= 0) {
-                pr_err("Illegal page count: %u for Ramdisk device\n",
-                        rd_dev->rd_page_count);
-                return -EINVAL;
-        }
-
-        /* Don't need backing pages for NULLIO */
-        if (rd_dev->rd_flags & RDF_NULLIO)
-                return 0;
-
-        total_sg_needed = rd_dev->rd_page_count;
-
-        sg_tables = (total_sg_needed / max_sg_per_table) + 1;
-
-        sg_table = kzalloc(sg_tables * sizeof(struct rd_dev_sg_table), GFP_KERNEL);
-        if (!sg_table) {
-                pr_err("Unable to allocate memory for Ramdisk"
-                        " scatterlist tables\n");
-                return -ENOMEM;
-        }
-
-        rd_dev->sg_table_array = sg_table;
-        rd_dev->sg_table_count = sg_tables;
+        unsigned char *p;
 
         while (total_sg_needed) {
                 sg_per_table = (total_sg_needed > max_sg_per_table) ?
@@ -186,16 +166,59 @@ static int rd_build_device_space(struct rd_dev *rd_dev)
                         }
                         sg_assign_page(&sg[j], pg);
                         sg[j].length = PAGE_SIZE;
+
+                        p = kmap(pg);
+                        memset(p, init_payload, PAGE_SIZE);
+                        kunmap(pg);
                 }
 
                 page_offset += sg_per_table;
                 total_sg_needed -= sg_per_table;
         }
 
+        return 0;
+}
+
+static int rd_build_device_space(struct rd_dev *rd_dev)
+{
+        struct rd_dev_sg_table *sg_table;
+        u32 sg_tables, total_sg_needed;
+        u32 max_sg_per_table = (RD_MAX_ALLOCATION_SIZE /
+                                sizeof(struct scatterlist));
+        int rc;
+
+        if (rd_dev->rd_page_count <= 0) {
+                pr_err("Illegal page count: %u for Ramdisk device\n",
+                       rd_dev->rd_page_count);
+                return -EINVAL;
+        }
+
+        /* Don't need backing pages for NULLIO */
+        if (rd_dev->rd_flags & RDF_NULLIO)
+                return 0;
+
+        total_sg_needed = rd_dev->rd_page_count;
+
+        sg_tables = (total_sg_needed / max_sg_per_table) + 1;
+
+        sg_table = kzalloc(sg_tables * sizeof(struct rd_dev_sg_table), GFP_KERNEL);
+        if (!sg_table) {
+                pr_err("Unable to allocate memory for Ramdisk"
+                       " scatterlist tables\n");
+                return -ENOMEM;
+        }
+
+        rd_dev->sg_table_array = sg_table;
+        rd_dev->sg_table_count = sg_tables;
+
+        rc = rd_allocate_sgl_table(rd_dev, sg_table, total_sg_needed, 0x00);
+        if (rc)
+                return rc;
+
         pr_debug("CORE_RD[%u] - Built Ramdisk Device ID: %u space of"
-                " %u pages in %u tables\n", rd_dev->rd_host->rd_host_id,
-                rd_dev->rd_dev_id, rd_dev->rd_page_count,
-                rd_dev->sg_table_count);
+                 " %u pages in %u tables\n", rd_dev->rd_host->rd_host_id,
+                 rd_dev->rd_dev_id, rd_dev->rd_page_count,
+                 rd_dev->sg_table_count);
 
         return 0;
 }