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[SCSI] ibmvscsi: handle large scatter/gather lists
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The maximum size of a scatter-gather list that the current IBM VSCSI
Client can handle is 10.  This patch adds large scatter-gather support
to the client so that it is capable of handling up to SG_ALL(255)
number of requests in the scatter-gather list.

Signed-off-by: Linda Xie <lxie@us.ibm.com>
Acked by: Dave C Boutcher <sleddog@us.ibm.com>

Rejections fixed up and
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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James Bottomley committed Sep 6, 2005
1 parent 1aab60c commit 4dddbc2
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Showing 2 changed files with 116 additions and 42 deletions.
156 changes: 114 additions & 42 deletions drivers/scsi/ibmvscsi/ibmvscsi.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -87,7 +87,7 @@ static int max_channel = 3;
static int init_timeout = 5;
static int max_requests = 50;

#define IBMVSCSI_VERSION "1.5.6"
#define IBMVSCSI_VERSION "1.5.7"

MODULE_DESCRIPTION("IBM Virtual SCSI");
MODULE_AUTHOR("Dave Boutcher");
Expand Down Expand Up @@ -145,6 +145,8 @@ static int initialize_event_pool(struct event_pool *pool,
sizeof(*evt->xfer_iu) * i;
evt->xfer_iu = pool->iu_storage + i;
evt->hostdata = hostdata;
evt->ext_list = NULL;
evt->ext_list_token = 0;
}

return 0;
Expand All @@ -161,9 +163,16 @@ static void release_event_pool(struct event_pool *pool,
struct ibmvscsi_host_data *hostdata)
{
int i, in_use = 0;
for (i = 0; i < pool->size; ++i)
for (i = 0; i < pool->size; ++i) {
if (atomic_read(&pool->events[i].free) != 1)
++in_use;
if (pool->events[i].ext_list) {
dma_free_coherent(hostdata->dev,
SG_ALL * sizeof(struct memory_descriptor),
pool->events[i].ext_list,
pool->events[i].ext_list_token);
}
}
if (in_use)
printk(KERN_WARNING
"ibmvscsi: releasing event pool with %d "
Expand Down Expand Up @@ -286,24 +295,41 @@ static void set_srp_direction(struct scsi_cmnd *cmd,
} else {
if (cmd->sc_data_direction == DMA_TO_DEVICE) {
srp_cmd->data_out_format = SRP_INDIRECT_BUFFER;
srp_cmd->data_out_count = numbuf;
srp_cmd->data_out_count =
numbuf < MAX_INDIRECT_BUFS ?
numbuf: MAX_INDIRECT_BUFS;
} else {
srp_cmd->data_in_format = SRP_INDIRECT_BUFFER;
srp_cmd->data_in_count = numbuf;
srp_cmd->data_in_count =
numbuf < MAX_INDIRECT_BUFS ?
numbuf: MAX_INDIRECT_BUFS;
}
}
}

static void unmap_sg_list(int num_entries,
struct device *dev,
struct memory_descriptor *md)
{
int i;

for (i = 0; i < num_entries; ++i) {
dma_unmap_single(dev,
md[i].virtual_address,
md[i].length, DMA_BIDIRECTIONAL);
}
}

/**
* unmap_cmd_data: - Unmap data pointed in srp_cmd based on the format
* @cmd: srp_cmd whose additional_data member will be unmapped
* @dev: device for which the memory is mapped
*
*/
static void unmap_cmd_data(struct srp_cmd *cmd, struct device *dev)
static void unmap_cmd_data(struct srp_cmd *cmd,
struct srp_event_struct *evt_struct,
struct device *dev)
{
int i;

if ((cmd->data_out_format == SRP_NO_BUFFER) &&
(cmd->data_in_format == SRP_NO_BUFFER))
return;
Expand All @@ -318,15 +344,34 @@ static void unmap_cmd_data(struct srp_cmd *cmd, struct device *dev)
(struct indirect_descriptor *)cmd->additional_data;
int num_mapped = indirect->head.length /
sizeof(indirect->list[0]);
for (i = 0; i < num_mapped; ++i) {
struct memory_descriptor *data = &indirect->list[i];
dma_unmap_single(dev,
data->virtual_address,
data->length, DMA_BIDIRECTIONAL);

if (num_mapped <= MAX_INDIRECT_BUFS) {
unmap_sg_list(num_mapped, dev, &indirect->list[0]);
return;
}

unmap_sg_list(num_mapped, dev, evt_struct->ext_list);
}
}

static int map_sg_list(int num_entries,
struct scatterlist *sg,
struct memory_descriptor *md)
{
int i;
u64 total_length = 0;

for (i = 0; i < num_entries; ++i) {
struct memory_descriptor *descr = md + i;
struct scatterlist *sg_entry = &sg[i];
descr->virtual_address = sg_dma_address(sg_entry);
descr->length = sg_dma_len(sg_entry);
descr->memory_handle = 0;
total_length += sg_dma_len(sg_entry);
}
return total_length;
}

/**
* map_sg_data: - Maps dma for a scatterlist and initializes decriptor fields
* @cmd: Scsi_Cmnd with the scatterlist
Expand All @@ -337,10 +382,11 @@ static void unmap_cmd_data(struct srp_cmd *cmd, struct device *dev)
* Returns 1 on success.
*/
static int map_sg_data(struct scsi_cmnd *cmd,
struct srp_event_struct *evt_struct,
struct srp_cmd *srp_cmd, struct device *dev)
{

int i, sg_mapped;
int sg_mapped;
u64 total_length = 0;
struct scatterlist *sg = cmd->request_buffer;
struct memory_descriptor *data =
Expand All @@ -363,27 +409,46 @@ static int map_sg_data(struct scsi_cmnd *cmd,
return 1;
}

if (sg_mapped > MAX_INDIRECT_BUFS) {
if (sg_mapped > SG_ALL) {
printk(KERN_ERR
"ibmvscsi: More than %d mapped sg entries, got %d\n",
MAX_INDIRECT_BUFS, sg_mapped);
SG_ALL, sg_mapped);
return 0;
}

indirect->head.virtual_address = 0;
indirect->head.length = sg_mapped * sizeof(indirect->list[0]);
indirect->head.memory_handle = 0;
for (i = 0; i < sg_mapped; ++i) {
struct memory_descriptor *descr = &indirect->list[i];
struct scatterlist *sg_entry = &sg[i];
descr->virtual_address = sg_dma_address(sg_entry);
descr->length = sg_dma_len(sg_entry);
descr->memory_handle = 0;
total_length += sg_dma_len(sg_entry);

if (sg_mapped <= MAX_INDIRECT_BUFS) {
total_length = map_sg_list(sg_mapped, sg, &indirect->list[0]);
indirect->total_length = total_length;
return 1;
}
indirect->total_length = total_length;

return 1;
/* get indirect table */
if (!evt_struct->ext_list) {
evt_struct->ext_list =(struct memory_descriptor*)
dma_alloc_coherent(dev,
SG_ALL * sizeof(struct memory_descriptor),
&evt_struct->ext_list_token, 0);
if (!evt_struct->ext_list) {
printk(KERN_ERR
"ibmvscsi: Can't allocate memory for indirect table\n");
return 0;

}
}

total_length = map_sg_list(sg_mapped, sg, evt_struct->ext_list);

indirect->total_length = total_length;
indirect->head.virtual_address = evt_struct->ext_list_token;
indirect->head.length = sg_mapped * sizeof(indirect->list[0]);
memcpy(indirect->list, evt_struct->ext_list,
MAX_INDIRECT_BUFS * sizeof(struct memory_descriptor));

return 1;
}

/**
Expand Down Expand Up @@ -428,6 +493,7 @@ static int map_single_data(struct scsi_cmnd *cmd,
* Returns 1 on success.
*/
static int map_data_for_srp_cmd(struct scsi_cmnd *cmd,
struct srp_event_struct *evt_struct,
struct srp_cmd *srp_cmd, struct device *dev)
{
switch (cmd->sc_data_direction) {
Expand All @@ -450,7 +516,7 @@ static int map_data_for_srp_cmd(struct scsi_cmnd *cmd,
if (!cmd->request_buffer)
return 1;
if (cmd->use_sg)
return map_sg_data(cmd, srp_cmd, dev);
return map_sg_data(cmd, evt_struct, srp_cmd, dev);
return map_single_data(cmd, srp_cmd, dev);
}

Expand Down Expand Up @@ -486,6 +552,7 @@ static int ibmvscsi_send_srp_event(struct srp_event_struct *evt_struct,
printk(KERN_WARNING
"ibmvscsi: Warning, request_limit exceeded\n");
unmap_cmd_data(&evt_struct->iu.srp.cmd,
evt_struct,
hostdata->dev);
free_event_struct(&hostdata->pool, evt_struct);
return SCSI_MLQUEUE_HOST_BUSY;
Expand Down Expand Up @@ -513,7 +580,7 @@ static int ibmvscsi_send_srp_event(struct srp_event_struct *evt_struct,
return 0;

send_error:
unmap_cmd_data(&evt_struct->iu.srp.cmd, hostdata->dev);
unmap_cmd_data(&evt_struct->iu.srp.cmd, evt_struct, hostdata->dev);

if ((cmnd = evt_struct->cmnd) != NULL) {
cmnd->result = DID_ERROR << 16;
Expand Down Expand Up @@ -551,6 +618,7 @@ static void handle_cmd_rsp(struct srp_event_struct *evt_struct)
rsp->sense_and_response_data,
rsp->sense_data_list_length);
unmap_cmd_data(&evt_struct->iu.srp.cmd,
evt_struct,
evt_struct->hostdata->dev);

if (rsp->doover)
Expand Down Expand Up @@ -583,6 +651,7 @@ static int ibmvscsi_queuecommand(struct scsi_cmnd *cmnd,
{
struct srp_cmd *srp_cmd;
struct srp_event_struct *evt_struct;
struct indirect_descriptor *indirect;
struct ibmvscsi_host_data *hostdata =
(struct ibmvscsi_host_data *)&cmnd->device->host->hostdata;
u16 lun = lun_from_dev(cmnd->device);
Expand All @@ -591,32 +660,32 @@ static int ibmvscsi_queuecommand(struct scsi_cmnd *cmnd,
if (!evt_struct)
return SCSI_MLQUEUE_HOST_BUSY;

init_event_struct(evt_struct,
handle_cmd_rsp,
VIOSRP_SRP_FORMAT,
cmnd->timeout_per_command/HZ);

evt_struct->cmnd = cmnd;
evt_struct->cmnd_done = done;

/* Set up the actual SRP IU */
srp_cmd = &evt_struct->iu.srp.cmd;
memset(srp_cmd, 0x00, sizeof(*srp_cmd));
srp_cmd->type = SRP_CMD_TYPE;
memcpy(srp_cmd->cdb, cmnd->cmnd, sizeof(cmnd->cmnd));
srp_cmd->lun = ((u64) lun) << 48;

if (!map_data_for_srp_cmd(cmnd, srp_cmd, hostdata->dev)) {
if (!map_data_for_srp_cmd(cmnd, evt_struct, srp_cmd, hostdata->dev)) {
printk(KERN_ERR "ibmvscsi: couldn't convert cmd to srp_cmd\n");
free_event_struct(&hostdata->pool, evt_struct);
return SCSI_MLQUEUE_HOST_BUSY;
}

init_event_struct(evt_struct,
handle_cmd_rsp,
VIOSRP_SRP_FORMAT,
cmnd->timeout_per_command/HZ);

evt_struct->cmnd = cmnd;
evt_struct->cmnd_done = done;

/* Fix up dma address of the buffer itself */
if ((srp_cmd->data_out_format == SRP_INDIRECT_BUFFER) ||
(srp_cmd->data_in_format == SRP_INDIRECT_BUFFER)) {
struct indirect_descriptor *indirect =
(struct indirect_descriptor *)srp_cmd->additional_data;
indirect = (struct indirect_descriptor *)srp_cmd->additional_data;
if (((srp_cmd->data_out_format == SRP_INDIRECT_BUFFER) ||
(srp_cmd->data_in_format == SRP_INDIRECT_BUFFER)) &&
(indirect->head.virtual_address == 0)) {
indirect->head.virtual_address = evt_struct->crq.IU_data_ptr +
offsetof(struct srp_cmd, additional_data) +
offsetof(struct indirect_descriptor, list);
Expand Down Expand Up @@ -931,7 +1000,8 @@ static int ibmvscsi_eh_abort_handler(struct scsi_cmnd *cmd)

cmd->result = (DID_ABORT << 16);
list_del(&found_evt->list);
unmap_cmd_data(&found_evt->iu.srp.cmd, found_evt->hostdata->dev);
unmap_cmd_data(&found_evt->iu.srp.cmd, found_evt,
found_evt->hostdata->dev);
free_event_struct(&found_evt->hostdata->pool, found_evt);
spin_unlock_irqrestore(hostdata->host->host_lock, flags);
atomic_inc(&hostdata->request_limit);
Expand Down Expand Up @@ -1023,7 +1093,8 @@ static int ibmvscsi_eh_device_reset_handler(struct scsi_cmnd *cmd)
if (tmp_evt->cmnd)
tmp_evt->cmnd->result = (DID_RESET << 16);
list_del(&tmp_evt->list);
unmap_cmd_data(&tmp_evt->iu.srp.cmd, tmp_evt->hostdata->dev);
unmap_cmd_data(&tmp_evt->iu.srp.cmd, tmp_evt,
tmp_evt->hostdata->dev);
free_event_struct(&tmp_evt->hostdata->pool,
tmp_evt);
atomic_inc(&hostdata->request_limit);
Expand Down Expand Up @@ -1052,6 +1123,7 @@ static void purge_requests(struct ibmvscsi_host_data *hostdata)
if (tmp_evt->cmnd) {
tmp_evt->cmnd->result = (DID_ERROR << 16);
unmap_cmd_data(&tmp_evt->iu.srp.cmd,
tmp_evt,
tmp_evt->hostdata->dev);
if (tmp_evt->cmnd_done)
tmp_evt->cmnd_done(tmp_evt->cmnd);
Expand Down Expand Up @@ -1356,7 +1428,7 @@ static struct scsi_host_template driver_template = {
.cmd_per_lun = 16,
.can_queue = 1, /* Updated after SRP_LOGIN */
.this_id = -1,
.sg_tablesize = MAX_INDIRECT_BUFS,
.sg_tablesize = SG_ALL,
.use_clustering = ENABLE_CLUSTERING,
.shost_attrs = ibmvscsi_attrs,
};
Expand Down
2 changes: 2 additions & 0 deletions drivers/scsi/ibmvscsi/ibmvscsi.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -68,6 +68,8 @@ struct srp_event_struct {
void (*cmnd_done) (struct scsi_cmnd *);
struct completion comp;
union viosrp_iu *sync_srp;
struct memory_descriptor *ext_list;
dma_addr_t ext_list_token;
};

/* a pool of event structs for use */
Expand Down

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