Hi
I am not clear on the remainder/remainder_size would not a single offset
parameter work? rather than copying it off and back?
also max_recs does not seem to used except to calculate max buffer size so
would not using a buffer size be easier?
something like bulk_req_read( int fd, struct io_thread_req *buf, size_t len,
size_t *offset)
+static int bulk_req_safe_read(
+ int fd,
+ struct io_thread_req * (*request_buffer)[],
+ struct io_thread_req **remainder,
+ int *remainder_size,
+ int max_recs
+ )
+{
+ int n = 0;
+ int res = 0;
+
+ if (*remainder_size > 0) {
+ memmove(
+ (char *) request_buffer,
+ (char *) remainder, *remainder_size
+ );
+ n = *remainder_size;
+ }
+
+ res = os_read_file(
+ fd,
+ ((char *) request_buffer) + *remainder_size,
+ sizeof(struct io_thread_req *)*max_recs
+ - *remainder_size
then here it would be
res = os_read_file(fd, buf+*offset,len-*offset)
Note that if this is ever multithreaded buf and offset or
request_buffer/remainder/remainder_size need to be kept separate
+ );
+ if (res > 0) {
+ n += res;
+ if ((n % sizeof(struct io_thread_req *)) > 0) {
+ /*
+ * Read somehow returned not a multiple of dword
+ * theoretically possible, but never observed in the
+ * wild, so read routine must be able to handle it
+ */
maybe this should have a WARN_ON since it should never occur?
+ *remainder_size = n % sizeof(struct io_thread_req *);
+ memmove(
+ remainder,
+ ((char *) request_buffer) +
+ n/sizeof(struct io_thread_req *),
+ *remainder_size
I am pretty sure the 2nd parameter is off. I think it should be:
((char *) request_buffer) +(n/sizeof(struct io_thread_req *))*sizeof(struct
io_thread_req *)
also copying it off to a shared static buffer?
+ );
+ n = n - *remainder_size;
+ }
+ } else {
+ n = res;
+ }
+ return n;
+}
+
/* Called without dev->lock held, and only in interrupt context. */
static void ubd_handler(void)
{
- struct io_thread_req *req;
struct ubd *ubd;
struct list_head *list, *next_ele;
unsigned long flags;
int n;
+ int count;
while(1){
- n = os_read_file(thread_fd, &req,
- sizeof(struct io_thread_req *));
- if(n != sizeof(req)){
if it is being rewritten n could just be the number of complete buffers for the
for loop below
+ n = bulk_req_safe_read(
+ thread_fd,
+ irq_req_buffer,
+ &irq_remainder,
+ &irq_remainder_size,
+ UBD_REQ_BUFFER_SIZE
+ );
+ if (n < 0) {
if(n == -EAGAIN)
break;
printk(KERN_ERR "spurious interrupt in ubd_handler, "
"err = %d\n", -n);
return;
}
-
- blk_end_request(req->req, 0, req->length);
- kfree(req);
+ for (count = 0; count < n/sizeof(struct io_thread_req *);
count++) {
+ blk_end_request(
+ (*irq_req_buffer)[count]->req,
+ 0,
+ (*irq_req_buffer)[count]->length
+ );
+ kfree((*irq_req_buffer)[count]);
+ }
}
reactivate_fd(thread_fd, UBD_IRQ);
@@ -1064,6 +1137,28 @@ static int __init ubd_init(void)
if (register_blkdev(fake_major, "ubd"))
return -1;
}
+
+ irq_req_buffer = kmalloc(
+ sizeof(struct io_thread_req *) * UBD_REQ_BUFFER_SIZE,
+ GFP_KERNEL
+ );
+ irq_remainder = 0;
+
+ if (irq_req_buffer == NULL) {
+ printk(KERN_ERR "Failed to initialize ubd buffering\n");
+ return -1;
+ }
Ok, I am really not tracking this, the same buffer allocated twice?
+ io_req_buffer = kmalloc(
+ sizeof(struct io_thread_req *) * UBD_REQ_BUFFER_SIZE,
+ GFP_KERNEL
+ );
+
+ io_remainder = 0;
+
+ if (io_req_buffer == NULL) {
+ printk(KERN_ERR "Failed to initialize ubd buffering\n");
+ return -1;
+ }
platform_driver_register(&ubd_driver);
mutex_lock(&ubd_lock);
for (i = 0; i < MAX_DEV; i++){
Sorry of the poor email I am using a web interface and it keeps dropping
chars...
Jim
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