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[SCSI] zfcp: code cleanup

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improve code for buffer enqueue. easy readability and maintainability.

Signed-off-by: Swen Schillig <swen@vnet.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
This commit is contained in:
Swen Schillig 2007-07-18 10:55:13 +02:00 committed by James Bottomley
parent aa551daf5c
commit b4e44590f0
2 changed files with 38 additions and 86 deletions
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1
drivers/s390/scsi/zfcp_def.h
View file

@ -126,6 +126,7 @@ zfcp_address_to_sg(void *address, struct scatterlist *list)
#define ZFCP_MIN_OUTPUT_THRESHOLD 1 /* ignored by QDIO layer */
#define QDIO_SCSI_QFMT 1 /* 1 for FSF */
#define QBUFF_PER_PAGE (PAGE_SIZE / sizeof(struct qdio_buffer))
/********************* FSF SPECIFIC DEFINES *********************************/

123
drivers/s390/scsi/zfcp_qdio.c
View file

@ -46,104 +46,57 @@ static int zfcp_qdio_handler_error_check(struct zfcp_adapter *,
#define ZFCP_LOG_AREA ZFCP_LOG_AREA_QDIO
/*
* Allocates BUFFER memory to each of the pointers of the qdio_buffer_t
* array in the adapter struct.
* Cur_buf is the pointer array and count can be any number of required
* buffers, the page-fitting arithmetic is done entirely within this funciton.
*
* returns: number of buffers allocated
* locks: must only be called with zfcp_data.config_sema taken
*/
static int
zfcp_qdio_buffers_enqueue(struct qdio_buffer **cur_buf, int count)
{
int buf_pos;
int qdio_buffers_per_page;
int page_pos = 0;
struct qdio_buffer *first_in_page = NULL;
qdio_buffers_per_page = PAGE_SIZE / sizeof (struct qdio_buffer);
ZFCP_LOG_TRACE("buffers_per_page=%d\n", qdio_buffers_per_page);
for (buf_pos = 0; buf_pos < count; buf_pos++) {
if (page_pos == 0) {
cur_buf[buf_pos] = (struct qdio_buffer *)
get_zeroed_page(GFP_KERNEL);
if (cur_buf[buf_pos] == NULL) {
ZFCP_LOG_INFO("error: allocation of "
"QDIO buffer failed \n");
goto out;
}
first_in_page = cur_buf[buf_pos];
} else {
cur_buf[buf_pos] = first_in_page + page_pos;
}
/* was initialised to zero */
page_pos++;
page_pos %= qdio_buffers_per_page;
}
out:
return buf_pos;
}
/*
* Frees BUFFER memory for each of the pointers of the struct qdio_buffer array
* in the adapter struct cur_buf is the pointer array and count can be any
* number of buffers in the array that should be freed starting from buffer 0
* in the adapter struct sbuf is the pointer array.
*
* locks: must only be called with zfcp_data.config_sema taken
*/
static void
zfcp_qdio_buffers_dequeue(struct qdio_buffer **cur_buf, int count)
zfcp_qdio_buffers_dequeue(struct qdio_buffer **sbuf)
{
int buf_pos;
int qdio_buffers_per_page;
int pos;
qdio_buffers_per_page = PAGE_SIZE / sizeof (struct qdio_buffer);
ZFCP_LOG_TRACE("buffers_per_page=%d\n", qdio_buffers_per_page);
for (pos = 0; pos < QDIO_MAX_BUFFERS_PER_Q; pos += QBUFF_PER_PAGE)
free_page((unsigned long) sbuf[pos]);
}
for (buf_pos = 0; buf_pos < count; buf_pos += qdio_buffers_per_page)
free_page((unsigned long) cur_buf[buf_pos]);
return;
/*
* Allocates BUFFER memory to each of the pointers of the qdio_buffer_t
* array in the adapter struct.
* Cur_buf is the pointer array
*
* returns: zero on success else -ENOMEM
* locks: must only be called with zfcp_data.config_sema taken
*/
static int
zfcp_qdio_buffers_enqueue(struct qdio_buffer **sbuf)
{
int pos;
for (pos = 0; pos < QDIO_MAX_BUFFERS_PER_Q; pos += QBUFF_PER_PAGE) {
sbuf[pos] = (struct qdio_buffer *) get_zeroed_page(GFP_KERNEL);
if (!sbuf[pos]) {
zfcp_qdio_buffers_dequeue(sbuf);
return -ENOMEM;
}
}
for (pos = 0; pos < QDIO_MAX_BUFFERS_PER_Q; pos++)
if (pos % QBUFF_PER_PAGE)
sbuf[pos] = sbuf[pos - 1] + 1;
return 0;
}
/* locks: must only be called with zfcp_data.config_sema taken */
int
zfcp_qdio_allocate_queues(struct zfcp_adapter *adapter)
{
int buffer_count;
int retval = 0;
int ret;
buffer_count =
zfcp_qdio_buffers_enqueue(&(adapter->request_queue.buffer[0]),
QDIO_MAX_BUFFERS_PER_Q);
if (buffer_count < QDIO_MAX_BUFFERS_PER_Q) {
ZFCP_LOG_DEBUG("only %d QDIO buffers allocated for request "
"queue\n", buffer_count);
zfcp_qdio_buffers_dequeue(&(adapter->request_queue.buffer[0]),
buffer_count);
retval = -ENOMEM;
goto out;
}
buffer_count =
zfcp_qdio_buffers_enqueue(&(adapter->response_queue.buffer[0]),
QDIO_MAX_BUFFERS_PER_Q);
if (buffer_count < QDIO_MAX_BUFFERS_PER_Q) {
ZFCP_LOG_DEBUG("only %d QDIO buffers allocated for response "
"queue", buffer_count);
zfcp_qdio_buffers_dequeue(&(adapter->response_queue.buffer[0]),
buffer_count);
ZFCP_LOG_TRACE("freeing request_queue buffers\n");
zfcp_qdio_buffers_dequeue(&(adapter->request_queue.buffer[0]),
QDIO_MAX_BUFFERS_PER_Q);
retval = -ENOMEM;
goto out;
}
out:
return retval;
ret = zfcp_qdio_buffers_enqueue(adapter->request_queue.buffer);
if (ret)
return ret;
return zfcp_qdio_buffers_enqueue(adapter->response_queue.buffer);
}
/* locks: must only be called with zfcp_data.config_sema taken */
@ -151,12 +104,10 @@ void
zfcp_qdio_free_queues(struct zfcp_adapter *adapter)
{
ZFCP_LOG_TRACE("freeing request_queue buffers\n");
zfcp_qdio_buffers_dequeue(&(adapter->request_queue.buffer[0]),
QDIO_MAX_BUFFERS_PER_Q);
zfcp_qdio_buffers_dequeue(adapter->request_queue.buffer);
ZFCP_LOG_TRACE("freeing response_queue buffers\n");
zfcp_qdio_buffers_dequeue(&(adapter->response_queue.buffer[0]),
QDIO_MAX_BUFFERS_PER_Q);
zfcp_qdio_buffers_dequeue(adapter->response_queue.buffer);
}
int