target: ->map_task_SG conversion to ->map_control_SG and ->map_data_SG

This patch breaks up the ->map_task_SG() backend call into two seperate
->map_control_SG() and ->map_data_SG() in order to better address
IBLOCK and pSCSI.  IBLOCK only allocates bios for ->map_data_SG(), and
pSCSI will allocate a struct request for both cases.

This patch fixes incorrect usage of ->map_task_SG() for all se_cmd descriptors
in transport_generic_new_cmd() by moving the call into it's proper location
directly inside of transport_allocate_data_tasks()

Reported-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

diff --git a/drivers/target/target_core_iblock.c b/drivers/target/target_core_iblock.c
index 251fc66..7e12341 100644 (file)
--- a/drivers/target/target_core_iblock.c
+++ b/drivers/target/target_core_iblock.c
@@ -591,7 +591,7 @@ static struct bio *iblock_get_bio(
        return bio;
 }
 
-static int iblock_map_task_SG(struct se_task *task)
+static int iblock_map_data_SG(struct se_task *task)
 {
        struct se_cmd *cmd = task->task_se_cmd;
        struct se_device *dev = cmd->se_dev;
@@ -755,7 +755,7 @@ static struct se_subsystem_api iblock_template = {
        .name                   = "iblock",
        .owner                  = THIS_MODULE,
        .transport_type         = TRANSPORT_PLUGIN_VHBA_PDEV,
-       .map_task_SG            = iblock_map_task_SG,
+       .map_data_SG            = iblock_map_data_SG,
        .attach_hba             = iblock_attach_hba,
        .detach_hba             = iblock_detach_hba,
        .allocate_virtdevice    = iblock_allocate_virtdevice,

diff --git a/drivers/target/target_core_pscsi.c b/drivers/target/target_core_pscsi.c
index a2ce599..2b7b0da 100644 (file)
--- a/drivers/target/target_core_pscsi.c
+++ b/drivers/target/target_core_pscsi.c
@@ -1049,7 +1049,7 @@ static inline struct bio *pscsi_get_bio(int sg_num)
        return bio;
 }
 
-static int __pscsi_map_task_SG(
+static int __pscsi_map_SG(
        struct se_task *task,
        struct scatterlist *task_sg,
        u32 task_sg_num,
@@ -1198,7 +1198,10 @@ fail:
        return ret;
 }
 
-static int pscsi_map_task_SG(struct se_task *task)
+/*
+ * pSCSI maps both ->map_control_SG() and ->map_data_SG() to a single call.
+ */
+static int pscsi_map_SG(struct se_task *task)
 {
        int ret;
 
@@ -1206,13 +1209,13 @@ static int pscsi_map_task_SG(struct se_task *task)
         * Setup the main struct request for the task->task_sg[] payload
         */
 
-       ret = __pscsi_map_task_SG(task, task->task_sg, task->task_sg_nents, 0);
+       ret = __pscsi_map_SG(task, task->task_sg, task->task_sg_nents, 0);
        if (ret >= 0 && task->task_sg_bidi) {
                /*
                 * If present, set up the extra BIDI-COMMAND SCSI READ
                 * struct request and payload.
                 */
-               ret = __pscsi_map_task_SG(task, task->task_sg_bidi,
+               ret = __pscsi_map_SG(task, task->task_sg_bidi,
                                        task->task_sg_nents, 1);
        }
 
@@ -1340,7 +1343,8 @@ static struct se_subsystem_api pscsi_template = {
        .owner                  = THIS_MODULE,
        .transport_type         = TRANSPORT_PLUGIN_PHBA_PDEV,
        .cdb_none               = pscsi_CDB_none,
-       .map_task_SG            = pscsi_map_task_SG,
+       .map_control_SG         = pscsi_map_SG,
+       .map_data_SG            = pscsi_map_SG,
        .attach_hba             = pscsi_attach_hba,
        .detach_hba             = pscsi_detach_hba,
        .pmode_enable_hba       = pscsi_pmode_enable_hba,

diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 55b6588..007cfc1 100644 (file)
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -4081,8 +4081,7 @@ static int transport_allocate_data_tasks(
        struct se_device *dev = cmd->se_dev;
        unsigned long flags;
        sector_t sectors;
-       int task_count;
-       int i;
+       int task_count, i, ret;
        sector_t dev_max_sectors = dev->se_sub_dev->se_dev_attrib.max_sectors;
        u32 sector_size = dev->se_sub_dev->se_dev_attrib.block_size;
        struct scatterlist *sg;
@@ -4129,7 +4128,7 @@ static int transport_allocate_data_tasks(
                        task->task_padded_sg = 1;
                }
 
-               task->task_sg = kmalloc(sizeof(struct scatterlist) * \
+               task->task_sg = kmalloc(sizeof(struct scatterlist) *
                                        task->task_sg_nents, GFP_KERNEL);
                if (!task->task_sg) {
                        cmd->se_dev->transport->free_task(task);
@@ -4157,6 +4156,20 @@ static int transport_allocate_data_tasks(
                list_add_tail(&task->t_list, &cmd->t_task_list);
                spin_unlock_irqrestore(&cmd->t_state_lock, flags);
        }
+       /*
+        * Now perform the memory map of task->task_sg[] into backend
+        * subsystem memory..
+        */
+       list_for_each_entry(task, &cmd->t_task_list, t_list) {
+               if (atomic_read(&task->task_sent))
+                       continue;
+               if (!dev->transport->map_data_SG)
+                       continue;
+
+               ret = dev->transport->map_data_SG(task);
+               if (ret < 0)
+                       return 0;
+       }
 
        return task_count;
 }
@@ -4196,8 +4209,8 @@ transport_allocate_control_task(struct se_cmd *cmd)
        spin_unlock_irqrestore(&cmd->t_state_lock, flags);
 
        if (cmd->se_cmd_flags & SCF_SCSI_CONTROL_SG_IO_CDB) {
-               if (dev->transport->map_task_SG)
-                       ret = dev->transport->map_task_SG(task);
+               if (dev->transport->map_control_SG)
+                       ret = dev->transport->map_control_SG(task);
        } else if (cmd->se_cmd_flags & SCF_SCSI_NON_DATA_CDB) {
                if (dev->transport->cdb_none)
                        ret = dev->transport->cdb_none(task);
@@ -4239,8 +4252,6 @@ static u32 transport_allocate_tasks(
         */
 int transport_generic_new_cmd(struct se_cmd *cmd)
 {
-       struct se_task *task;
-       struct se_device *dev = cmd->se_dev;
        int ret = 0;
 
        /*
@@ -4254,22 +4265,16 @@ int transport_generic_new_cmd(struct se_cmd *cmd)
                if (ret < 0)
                        return ret;
        }
-
+       /*
+        * Call transport_new_cmd_obj() to invoke transport_allocate_tasks() for
+        * control or data CDB types, and perform the map to backend subsystem
+        * code from SGL memory allocated here by transport_generic_get_mem(), or
+        * via pre-existing SGL memory setup explictly by fabric module code with
+        * transport_generic_map_mem_to_cmd().
+        */
        ret = transport_new_cmd_obj(cmd);
        if (ret < 0)
                return ret;
-
-       list_for_each_entry(task, &cmd->t_task_list, t_list) {
-               if (atomic_read(&task->task_sent))
-                       continue;
-               if (!dev->transport->map_task_SG)
-                       continue;
-
-               ret = dev->transport->map_task_SG(task);
-               if (ret < 0)
-                       return ret;
-       }
-
        /*
         * For WRITEs, let the fabric know its buffer is ready..
         * This WRITE struct se_cmd (and all of its associated struct se_task's)

diff --git a/include/target/target_core_transport.h b/include/target/target_core_transport.h
index 7409576..54af39d 100644 (file)
--- a/include/target/target_core_transport.h
+++ b/include/target/target_core_transport.h
@@ -239,9 +239,13 @@ struct se_subsystem_api {
         */
        int (*cdb_none)(struct se_task *);
        /*
-        * For SCF_SCSI_DATA_SG_IO_CDB and SCF_SCSI_CONTROL_SG_IO_CDB
+        * For SCF_SCSI_DATA_SG_IO_CDB
         */
-       int (*map_task_SG)(struct se_task *);
+       int (*map_data_SG)(struct se_task *);
+       /*
+        * For SCF_SCSI_CONTROL_SG_IO_CDB
+        */
+       int (*map_control_SG)(struct se_task *);
        /*
         * attach_hba():
         */