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Diffstat (limited to 'arch/um/drivers/ubd_kern.c')
-rw-r--r--arch/um/drivers/ubd_kern.c176
1 files changed, 99 insertions, 77 deletions
diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index 6d163c9e288..5ef47b73ce9 100644
--- a/arch/um/drivers/ubd_kern.c
+++ b/arch/um/drivers/ubd_kern.c
@@ -149,7 +149,10 @@ struct cow {
int data_offset;
};
+#define MAX_SG 64
+
struct ubd {
+ struct list_head restart;
/* name (and fd, below) of the file opened for writing, either the
* backing or the cow file. */
char *file;
@@ -164,7 +167,9 @@ struct ubd {
struct platform_device pdev;
struct request_queue *queue;
spinlock_t lock;
- int active;
+ struct scatterlist sg[MAX_SG];
+ struct request *request;
+ int start_sg, end_sg;
};
#define DEFAULT_COW { \
@@ -186,7 +191,9 @@ struct ubd {
.shared = 0, \
.cow = DEFAULT_COW, \
.lock = SPIN_LOCK_UNLOCKED, \
- .active = 0, \
+ .request = NULL, \
+ .start_sg = 0, \
+ .end_sg = 0, \
}
/* Protected by ubd_lock */
@@ -466,60 +473,67 @@ static void do_ubd_request(request_queue_t * q);
/* Only changed by ubd_init, which is an initcall. */
int thread_fd = -1;
-/* call ubd_finish if you need to serialize */
-static void __ubd_finish(struct request *req, int error)
+static void ubd_end_request(struct request *req, int bytes, int uptodate)
{
- int nsect;
-
- if(error){
- end_request(req, 0);
- return;
+ if (!end_that_request_first(req, uptodate, bytes >> 9)) {
+ struct ubd *dev = req->rq_disk->private_data;
+ unsigned long flags;
+
+ add_disk_randomness(req->rq_disk);
+ spin_lock_irqsave(&dev->lock, flags);
+ end_that_request_last(req, uptodate);
+ spin_unlock_irqrestore(&dev->lock, flags);
}
- nsect = req->current_nr_sectors;
- req->sector += nsect;
- req->buffer += nsect << 9;
- req->errors = 0;
- req->nr_sectors -= nsect;
- req->current_nr_sectors = 0;
- end_request(req, 1);
}
/* Callable only from interrupt context - otherwise you need to do
* spin_lock_irq()/spin_lock_irqsave() */
-static inline void ubd_finish(struct request *req, int error)
+static inline void ubd_finish(struct request *req, int bytes)
{
- struct ubd *dev = req->rq_disk->private_data;
-
- spin_lock(&dev->lock);
- __ubd_finish(req, error);
- spin_unlock(&dev->lock);
+ if(bytes < 0){
+ ubd_end_request(req, 0, 0);
+ return;
+ }
+ ubd_end_request(req, bytes, 1);
}
+static LIST_HEAD(restart);
+
/* XXX - move this inside ubd_intr. */
/* Called without dev->lock held, and only in interrupt context. */
static void ubd_handler(void)
{
struct io_thread_req req;
struct request *rq;
- struct ubd *dev;
+ struct ubd *ubd;
+ struct list_head *list, *next_ele;
+ unsigned long flags;
int n;
- n = os_read_file_k(thread_fd, &req, sizeof(req));
- if(n != sizeof(req)){
- printk(KERN_ERR "Pid %d - spurious interrupt in ubd_handler, "
- "err = %d\n", os_getpid(), -n);
- return;
- }
-
- rq = req.req;
- dev = rq->rq_disk->private_data;
- dev->active = 0;
+ while(1){
+ n = os_read_file_k(thread_fd, &req, sizeof(req));
+ if(n != sizeof(req)){
+ if(n == -EAGAIN)
+ break;
+ printk(KERN_ERR "spurious interrupt in ubd_handler, "
+ "err = %d\n", -n);
+ return;
+ }
- ubd_finish(rq, req.error);
+ rq = req.req;
+ rq->nr_sectors -= req.length >> 9;
+ if(rq->nr_sectors == 0)
+ ubd_finish(rq, rq->hard_nr_sectors << 9);
+ }
reactivate_fd(thread_fd, UBD_IRQ);
- spin_lock(&dev->lock);
- do_ubd_request(dev->queue);
- spin_unlock(&dev->lock);
+
+ list_for_each_safe(list, next_ele, &restart){
+ ubd = container_of(list, struct ubd, restart);
+ list_del_init(&ubd->restart);
+ spin_lock_irqsave(&ubd->lock, flags);
+ do_ubd_request(ubd->queue);
+ spin_unlock_irqrestore(&ubd->lock, flags);
+ }
}
static irqreturn_t ubd_intr(int irq, void *dev)
@@ -684,6 +698,8 @@ static int ubd_add(int n, char **error_out)
ubd_dev->size = ROUND_BLOCK(ubd_dev->size);
+ INIT_LIST_HEAD(&ubd_dev->restart);
+
err = -ENOMEM;
ubd_dev->queue = blk_init_queue(do_ubd_request, &ubd_dev->lock);
if (ubd_dev->queue == NULL) {
@@ -692,6 +708,7 @@ static int ubd_add(int n, char **error_out)
}
ubd_dev->queue->queuedata = ubd_dev;
+ blk_queue_max_hw_segments(ubd_dev->queue, MAX_SG);
err = ubd_disk_register(MAJOR_NR, ubd_dev->size, n, &ubd_gendisk[n]);
if(err){
*error_out = "Failed to register device";
@@ -1029,26 +1046,16 @@ static void cowify_req(struct io_thread_req *req, unsigned long *bitmap,
}
/* Called with dev->lock held */
-static int prepare_request(struct request *req, struct io_thread_req *io_req)
+static void prepare_request(struct request *req, struct io_thread_req *io_req,
+ unsigned long long offset, int page_offset,
+ int len, struct page *page)
{
struct gendisk *disk = req->rq_disk;
struct ubd *ubd_dev = disk->private_data;
- __u64 offset;
- int len;
-
- /* This should be impossible now */
- if((rq_data_dir(req) == WRITE) && !ubd_dev->openflags.w){
- printk("Write attempted on readonly ubd device %s\n",
- disk->disk_name);
- end_request(req, 0);
- return(1);
- }
-
- offset = ((__u64) req->sector) << 9;
- len = req->current_nr_sectors << 9;
io_req->req = req;
- io_req->fds[0] = (ubd_dev->cow.file != NULL) ? ubd_dev->cow.fd : ubd_dev->fd;
+ io_req->fds[0] = (ubd_dev->cow.file != NULL) ? ubd_dev->cow.fd :
+ ubd_dev->fd;
io_req->fds[1] = ubd_dev->fd;
io_req->cow_offset = -1;
io_req->offset = offset;
@@ -1059,14 +1066,13 @@ static int prepare_request(struct request *req, struct io_thread_req *io_req)
io_req->op = (rq_data_dir(req) == READ) ? UBD_READ : UBD_WRITE;
io_req->offsets[0] = 0;
io_req->offsets[1] = ubd_dev->cow.data_offset;
- io_req->buffer = req->buffer;
+ io_req->buffer = page_address(page) + page_offset;
io_req->sectorsize = 1 << 9;
if(ubd_dev->cow.file != NULL)
- cowify_req(io_req, ubd_dev->cow.bitmap, ubd_dev->cow.bitmap_offset,
- ubd_dev->cow.bitmap_len);
+ cowify_req(io_req, ubd_dev->cow.bitmap,
+ ubd_dev->cow.bitmap_offset, ubd_dev->cow.bitmap_len);
- return(0);
}
/* Called with dev->lock held */
@@ -1074,29 +1080,45 @@ static void do_ubd_request(request_queue_t *q)
{
struct io_thread_req io_req;
struct request *req;
- int err, n;
-
- if(thread_fd == -1){
- while((req = elv_next_request(q)) != NULL){
- err = prepare_request(req, &io_req);
- if(!err){
- do_io(&io_req);
- __ubd_finish(req, io_req.error);
- }
- }
- }
- else {
+ int n;
+
+ while(1){
struct ubd *dev = q->queuedata;
- if(dev->active || (req = elv_next_request(q)) == NULL)
- return;
- err = prepare_request(req, &io_req);
- if(!err){
- dev->active = 1;
- n = os_write_file_k(thread_fd, &io_req, sizeof(io_req));
- if(n != sizeof(io_req))
- printk("write to io thread failed, "
- "errno = %d\n", -n);
+ if(dev->end_sg == 0){
+ struct request *req = elv_next_request(q);
+ if(req == NULL)
+ return;
+
+ dev->request = req;
+ blkdev_dequeue_request(req);
+ dev->start_sg = 0;
+ dev->end_sg = blk_rq_map_sg(q, req, dev->sg);
+ }
+
+ req = dev->request;
+ while(dev->start_sg < dev->end_sg){
+ struct scatterlist *sg = &dev->sg[dev->start_sg];
+
+ prepare_request(req, &io_req,
+ (unsigned long long) req->sector << 9,
+ sg->offset, sg->length, sg->page);
+
+ n = os_write_file_k(thread_fd, (char *) &io_req,
+ sizeof(io_req));
+ if(n != sizeof(io_req)){
+ if(n != -EAGAIN)
+ printk("write to io thread failed, "
+ "errno = %d\n", -n);
+ else if(list_empty(&dev->restart))
+ list_add(&dev->restart, &restart);
+ return;
+ }
+
+ req->sector += sg->length >> 9;
+ dev->start_sg++;
}
+ dev->end_sg = 0;
+ dev->request = NULL;
}
}