diff options
Diffstat (limited to 'arch/um/drivers/ubd_kern.c')
-rw-r--r-- | arch/um/drivers/ubd_kern.c | 566 |
1 files changed, 316 insertions, 250 deletions
diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c index e77a38da435..93898917cbe 100644 --- a/arch/um/drivers/ubd_kern.c +++ b/arch/um/drivers/ubd_kern.c @@ -35,7 +35,7 @@ #include "linux/blkpg.h" #include "linux/genhd.h" #include "linux/spinlock.h" -#include "asm/atomic.h" +#include "linux/platform_device.h" #include "asm/segment.h" #include "asm/uaccess.h" #include "asm/irq.h" @@ -54,21 +54,20 @@ #include "mem.h" #include "mem_kern.h" #include "cow.h" -#include "aio.h" enum ubd_req { UBD_READ, UBD_WRITE }; struct io_thread_req { - enum aio_type op; + enum ubd_req op; int fds[2]; unsigned long offsets[2]; unsigned long long offset; unsigned long length; char *buffer; int sectorsize; - int bitmap_offset; - long bitmap_start; - long bitmap_end; + unsigned long sector_mask; + unsigned long long cow_offset; + unsigned long bitmap_words[2]; int error; }; @@ -82,31 +81,28 @@ extern int create_cow_file(char *cow_file, char *backing_file, unsigned long *bitmap_len_out, int *data_offset_out); extern int read_cow_bitmap(int fd, void *buf, int offset, int len); -extern void do_io(struct io_thread_req *req, struct request *r, - unsigned long *bitmap); +extern void do_io(struct io_thread_req *req); -static inline int ubd_test_bit(__u64 bit, void *data) +static inline int ubd_test_bit(__u64 bit, unsigned char *data) { - unsigned char *buffer = data; __u64 n; int bits, off; - bits = sizeof(buffer[0]) * 8; + bits = sizeof(data[0]) * 8; n = bit / bits; off = bit % bits; - return((buffer[n] & (1 << off)) != 0); + return((data[n] & (1 << off)) != 0); } -static inline void ubd_set_bit(__u64 bit, void *data) +static inline void ubd_set_bit(__u64 bit, unsigned char *data) { - unsigned char *buffer = data; __u64 n; int bits, off; - bits = sizeof(buffer[0]) * 8; + bits = sizeof(data[0]) * 8; n = bit / bits; off = bit % bits; - buffer[n] |= (1 << off); + data[n] |= (1 << off); } /*End stuff from ubd_user.h*/ @@ -115,6 +111,8 @@ static inline void ubd_set_bit(__u64 bit, void *data) static DEFINE_SPINLOCK(ubd_io_lock); static DEFINE_SPINLOCK(ubd_lock); +static void (*do_ubd)(void); + static int ubd_open(struct inode * inode, struct file * filp); static int ubd_release(struct inode * inode, struct file * file); static int ubd_ioctl(struct inode * inode, struct file * file, @@ -161,8 +159,6 @@ struct cow { int data_offset; }; -#define MAX_SG 64 - struct ubd { char *file; int count; @@ -173,7 +169,6 @@ struct ubd { int no_cow; struct cow cow; struct platform_device pdev; - struct scatterlist sg[MAX_SG]; }; #define DEFAULT_COW { \ @@ -466,114 +461,81 @@ __uml_help(fakehd, ); static void do_ubd_request(request_queue_t * q); -static int in_ubd; + +/* Only changed by ubd_init, which is an initcall. */ +int thread_fd = -1; /* Changed by ubd_handler, which is serialized because interrupts only * happen on CPU 0. */ int intr_count = 0; -static void ubd_end_request(struct request *req, int bytes, int uptodate) +/* call ubd_finish if you need to serialize */ +static void __ubd_finish(struct request *req, int error) { - if (!end_that_request_first(req, uptodate, bytes >> 9)) { - add_disk_randomness(req->rq_disk); - end_that_request_last(req); + int nsect; + + if(error){ + end_request(req, 0); + return; } + 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); } -/* call ubd_finish if you need to serialize */ -static void __ubd_finish(struct request *req, int bytes) +static inline void ubd_finish(struct request *req, int error) { - if(bytes < 0){ - ubd_end_request(req, 0, 0); - return; - } - - ubd_end_request(req, bytes, 1); + spin_lock(&ubd_io_lock); + __ubd_finish(req, error); + spin_unlock(&ubd_io_lock); } -static inline void ubd_finish(struct request *req, int bytes) +/* Called without ubd_io_lock held */ +static void ubd_handler(void) { - spin_lock(&ubd_io_lock); - __ubd_finish(req, bytes); - spin_unlock(&ubd_io_lock); + struct io_thread_req req; + struct request *rq = elv_next_request(ubd_queue); + int n; + + do_ubd = NULL; + intr_count++; + n = os_read_file(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); + spin_lock(&ubd_io_lock); + end_request(rq, 0); + spin_unlock(&ubd_io_lock); + return; + } + + ubd_finish(rq, req.error); + reactivate_fd(thread_fd, UBD_IRQ); + do_ubd_request(ubd_queue); } -struct bitmap_io { - atomic_t count; - struct aio_context aio; -}; - -struct ubd_aio { - struct aio_context aio; - struct request *req; - int len; - struct bitmap_io *bitmap; - void *bitmap_buf; -}; - -static int ubd_reply_fd = -1; - static irqreturn_t ubd_intr(int irq, void *dev, struct pt_regs *unused) { - struct aio_thread_reply reply; - struct ubd_aio *aio; - struct request *req; - int err, n, fd = (int) (long) dev; - - while(1){ - err = os_read_file(fd, &reply, sizeof(reply)); - if(err == -EAGAIN) - break; - if(err < 0){ - printk("ubd_aio_handler - read returned err %d\n", - -err); - break; - } - - aio = container_of(reply.data, struct ubd_aio, aio); - n = reply.err; - - if(n == 0){ - req = aio->req; - req->nr_sectors -= aio->len >> 9; - - if((aio->bitmap != NULL) && - (atomic_dec_and_test(&aio->bitmap->count))){ - aio->aio = aio->bitmap->aio; - aio->len = 0; - kfree(aio->bitmap); - aio->bitmap = NULL; - submit_aio(&aio->aio); - } - else { - if((req->nr_sectors == 0) && - (aio->bitmap == NULL)){ - int len = req->hard_nr_sectors << 9; - ubd_finish(req, len); - } - - if(aio->bitmap_buf != NULL) - kfree(aio->bitmap_buf); - kfree(aio); - } - } - else if(n < 0){ - ubd_finish(aio->req, n); - if(aio->bitmap != NULL) - kfree(aio->bitmap); - if(aio->bitmap_buf != NULL) - kfree(aio->bitmap_buf); - kfree(aio); - } - } - reactivate_fd(fd, UBD_IRQ); + ubd_handler(); + return(IRQ_HANDLED); +} - do_ubd_request(ubd_queue); +/* Only changed by ubd_init, which is an initcall. */ +static int io_pid = -1; - return(IRQ_HANDLED); +void kill_io_thread(void) +{ + if(io_pid != -1) + os_kill_process(io_pid, 1); } +__uml_exitcall(kill_io_thread); + static int ubd_file_size(struct ubd *dev, __u64 *size_out) { char *file; @@ -608,7 +570,7 @@ static int ubd_open_dev(struct ubd *dev) &dev->cow.data_offset, create_ptr); if((dev->fd == -ENOENT) && create_cow){ - dev->fd = create_cow_file(dev->file, dev->cow.file, + dev->fd = create_cow_file(dev->file, dev->cow.file, dev->openflags, 1 << 9, PAGE_SIZE, &dev->cow.bitmap_offset, &dev->cow.bitmap_len, @@ -861,19 +823,16 @@ static int ubd_mc_init(void) __initcall(ubd_mc_init); -static struct device_driver ubd_driver = { - .name = DRIVER_NAME, - .bus = &platform_bus_type, +static struct platform_driver ubd_driver = { + .driver = { + .name = DRIVER_NAME, + }, }; int ubd_init(void) { int i; - ubd_reply_fd = init_aio_irq(UBD_IRQ, "ubd", ubd_intr); - if(ubd_reply_fd < 0) - printk("Setting up ubd AIO failed, err = %d\n", ubd_reply_fd); - devfs_mk_dir("ubd"); if (register_blkdev(MAJOR_NR, "ubd")) return -1; @@ -884,7 +843,6 @@ int ubd_init(void) return -1; } - blk_queue_max_hw_segments(ubd_queue, MAX_SG); if (fake_major != MAJOR_NR) { char name[sizeof("ubd_nnn\0")]; @@ -893,15 +851,43 @@ int ubd_init(void) if (register_blkdev(fake_major, "ubd")) return -1; } - driver_register(&ubd_driver); + platform_driver_register(&ubd_driver); for (i = 0; i < MAX_DEV; i++) ubd_add(i); - return 0; } late_initcall(ubd_init); +int ubd_driver_init(void){ + unsigned long stack; + int err; + + /* Set by CONFIG_BLK_DEV_UBD_SYNC or ubd=sync.*/ + if(global_openflags.s){ + printk(KERN_INFO "ubd: Synchronous mode\n"); + /* Letting ubd=sync be like using ubd#s= instead of ubd#= is + * enough. So use anyway the io thread. */ + } + stack = alloc_stack(0, 0); + io_pid = start_io_thread(stack + PAGE_SIZE - sizeof(void *), + &thread_fd); + if(io_pid < 0){ + printk(KERN_ERR + "ubd : Failed to start I/O thread (errno = %d) - " + "falling back to synchronous I/O\n", -io_pid); + io_pid = -1; + return(0); + } + err = um_request_irq(UBD_IRQ, thread_fd, IRQ_READ, ubd_intr, + SA_INTERRUPT, "ubd", ubd_dev); + if(err != 0) + printk(KERN_ERR "um_request_irq failed - errno = %d\n", -err); + return(err); +} + +device_initcall(ubd_driver_init); + static int ubd_open(struct inode *inode, struct file *filp) { struct gendisk *disk = inode->i_bdev->bd_disk; @@ -939,55 +925,105 @@ static int ubd_release(struct inode * inode, struct file * file) return(0); } -static void cowify_bitmap(struct io_thread_req *req, unsigned long *bitmap) +static void cowify_bitmap(__u64 io_offset, int length, unsigned long *cow_mask, + __u64 *cow_offset, unsigned long *bitmap, + __u64 bitmap_offset, unsigned long *bitmap_words, + __u64 bitmap_len) { - __u64 sector = req->offset / req->sectorsize; - int i; + __u64 sector = io_offset >> 9; + int i, update_bitmap = 0; + + for(i = 0; i < length >> 9; i++){ + if(cow_mask != NULL) + ubd_set_bit(i, (unsigned char *) cow_mask); + if(ubd_test_bit(sector + i, (unsigned char *) bitmap)) + continue; - for(i = 0; i < req->length / req->sectorsize; i++){ - if(ubd_test_bit(sector + i, bitmap)) - continue; + update_bitmap = 1; + ubd_set_bit(sector + i, (unsigned char *) bitmap); + } + + if(!update_bitmap) + return; - if(req->bitmap_start == -1) - req->bitmap_start = sector + i; - req->bitmap_end = sector + i + 1; + *cow_offset = sector / (sizeof(unsigned long) * 8); - ubd_set_bit(sector + i, bitmap); - } + /* This takes care of the case where we're exactly at the end of the + * device, and *cow_offset + 1 is off the end. So, just back it up + * by one word. Thanks to Lynn Kerby for the fix and James McMechan + * for the original diagnosis. + */ + if(*cow_offset == ((bitmap_len + sizeof(unsigned long) - 1) / + sizeof(unsigned long) - 1)) + (*cow_offset)--; + + bitmap_words[0] = bitmap[*cow_offset]; + bitmap_words[1] = bitmap[*cow_offset + 1]; + + *cow_offset *= sizeof(unsigned long); + *cow_offset += bitmap_offset; +} + +static void cowify_req(struct io_thread_req *req, unsigned long *bitmap, + __u64 bitmap_offset, __u64 bitmap_len) +{ + __u64 sector = req->offset >> 9; + int i; + + if(req->length > (sizeof(req->sector_mask) * 8) << 9) + panic("Operation too long"); + + if(req->op == UBD_READ) { + for(i = 0; i < req->length >> 9; i++){ + if(ubd_test_bit(sector + i, (unsigned char *) bitmap)) + ubd_set_bit(i, (unsigned char *) + &req->sector_mask); + } + } + else cowify_bitmap(req->offset, req->length, &req->sector_mask, + &req->cow_offset, bitmap, bitmap_offset, + req->bitmap_words, bitmap_len); } /* Called with ubd_io_lock held */ -static int prepare_request(struct request *req, struct io_thread_req *io_req, - unsigned long long offset, int page_offset, - int len, struct page *page) +static int prepare_request(struct request *req, struct io_thread_req *io_req) { struct gendisk *disk = req->rq_disk; struct ubd *dev = disk->private_data; + __u64 offset; + int len; + + if(req->rq_status == RQ_INACTIVE) return(1); /* This should be impossible now */ if((rq_data_dir(req) == WRITE) && !dev->openflags.w){ printk("Write attempted on readonly ubd device %s\n", disk->disk_name); - ubd_end_request(req, 0, 0); + end_request(req, 0); return(1); } + offset = ((__u64) req->sector) << 9; + len = req->current_nr_sectors << 9; + io_req->fds[0] = (dev->cow.file != NULL) ? dev->cow.fd : dev->fd; io_req->fds[1] = dev->fd; + io_req->cow_offset = -1; io_req->offset = offset; io_req->length = len; io_req->error = 0; - io_req->op = (rq_data_dir(req) == READ) ? AIO_READ : AIO_WRITE; + io_req->sector_mask = 0; + + io_req->op = (rq_data_dir(req) == READ) ? UBD_READ : UBD_WRITE; io_req->offsets[0] = 0; io_req->offsets[1] = dev->cow.data_offset; - io_req->buffer = page_address(page) + page_offset; + io_req->buffer = req->buffer; io_req->sectorsize = 1 << 9; - io_req->bitmap_offset = dev->cow.bitmap_offset; - io_req->bitmap_start = -1; - io_req->bitmap_end = -1; - if((dev->cow.file != NULL) && (io_req->op == UBD_WRITE)) - cowify_bitmap(io_req, dev->cow.bitmap); + if(dev->cow.file != NULL) + cowify_req(io_req, dev->cow.bitmap, dev->cow.bitmap_offset, + dev->cow.bitmap_len); + return(0); } @@ -996,36 +1032,30 @@ static void do_ubd_request(request_queue_t *q) { struct io_thread_req io_req; struct request *req; - __u64 sector; - int err; - - if(in_ubd) - return; - in_ubd = 1; - while((req = elv_next_request(q)) != NULL){ - struct gendisk *disk = req->rq_disk; - struct ubd *dev = disk->private_data; - int n, i; - - blkdev_dequeue_request(req); - - sector = req->sector; - n = blk_rq_map_sg(q, req, dev->sg); - - for(i = 0; i < n; i++){ - struct scatterlist *sg = &dev->sg[i]; - - err = prepare_request(req, &io_req, sector << 9, - sg->offset, sg->length, - sg->page); - if(err) - continue; - - sector += sg->length >> 9; - do_io(&io_req, req, dev->cow.bitmap); + 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 { + if(do_ubd || (req = elv_next_request(q)) == NULL) + return; + err = prepare_request(req, &io_req); + if(!err){ + do_ubd = ubd_handler; + n = os_write_file(thread_fd, (char *) &io_req, + sizeof(io_req)); + if(n != sizeof(io_req)) + printk("write to io thread failed, " + "errno = %d\n", -n); } } - in_ubd = 0; } static int ubd_ioctl(struct inode * inode, struct file * file, @@ -1241,95 +1271,131 @@ int create_cow_file(char *cow_file, char *backing_file, struct openflags flags, return(err); } -void do_io(struct io_thread_req *req, struct request *r, unsigned long *bitmap) +static int update_bitmap(struct io_thread_req *req) { - struct ubd_aio *aio; - struct bitmap_io *bitmap_io = NULL; - char *buf; - void *bitmap_buf = NULL; - unsigned long len, sector; - int nsectors, start, end, bit, err; - __u64 off; - - if(req->bitmap_start != -1){ - /* Round up to the nearest word */ - int round = sizeof(unsigned long); - len = (req->bitmap_end - req->bitmap_start + - round * 8 - 1) / (round * 8); - len *= round; - - off = req->bitmap_start / (8 * round); - off *= round; - - bitmap_io = kmalloc(sizeof(*bitmap_io), GFP_KERNEL); - if(bitmap_io == NULL){ - printk("Failed to kmalloc bitmap IO\n"); - req->error = 1; - return; - } + int n; - bitmap_buf = kmalloc(len, GFP_KERNEL); - if(bitmap_buf == NULL){ - printk("do_io : kmalloc of bitmap chunk " - "failed\n"); - kfree(bitmap_io); - req->error = 1; - return; - } - memcpy(bitmap_buf, &bitmap[off / sizeof(bitmap[0])], len); - - *bitmap_io = ((struct bitmap_io) - { .count = ATOMIC_INIT(0), - .aio = INIT_AIO(AIO_WRITE, req->fds[1], - bitmap_buf, len, - req->bitmap_offset + off, - ubd_reply_fd) } ); - } + if(req->cow_offset == -1) + return(0); - nsectors = req->length / req->sectorsize; - start = 0; - end = nsectors; - bit = 0; - do { - if(bitmap != NULL){ - sector = req->offset / req->sectorsize; - bit = ubd_test_bit(sector + start, bitmap); - end = start; - while((end < nsectors) && - (ubd_test_bit(sector + end, bitmap) == bit)) - end++; - } + n = os_seek_file(req->fds[1], req->cow_offset); + if(n < 0){ + printk("do_io - bitmap lseek failed : err = %d\n", -n); + return(1); + } - off = req->offsets[bit] + req->offset + - start * req->sectorsize; - len = (end - start) * req->sectorsize; - buf = &req->buffer[start * req->sectorsize]; + n = os_write_file(req->fds[1], &req->bitmap_words, + sizeof(req->bitmap_words)); + if(n != sizeof(req->bitmap_words)){ + printk("do_io - bitmap update failed, err = %d fd = %d\n", -n, + req->fds[1]); + return(1); + } - aio = kmalloc(sizeof(*aio), GFP_KERNEL); - if(aio == NULL){ - req->error = 1; - return; - } + return(0); +} - *aio = ((struct ubd_aio) - { .aio = INIT_AIO(req->op, req->fds[bit], buf, - len, off, ubd_reply_fd), - .len = len, - .req = r, - .bitmap = bitmap_io, - .bitmap_buf = bitmap_buf }); - - if(aio->bitmap != NULL) - atomic_inc(&aio->bitmap->count); - - err = submit_aio(&aio->aio); - if(err){ - printk("do_io - submit_aio failed, " - "err = %d\n", err); - req->error = 1; - return; - } +void do_io(struct io_thread_req *req) +{ + char *buf; + unsigned long len; + int n, nsectors, start, end, bit; + int err; + __u64 off; + + nsectors = req->length / req->sectorsize; + start = 0; + do { + bit = ubd_test_bit(start, (unsigned char *) &req->sector_mask); + end = start; + while((end < nsectors) && + (ubd_test_bit(end, (unsigned char *) + &req->sector_mask) == bit)) + end++; + + off = req->offset + req->offsets[bit] + + start * req->sectorsize; + len = (end - start) * req->sectorsize; + buf = &req->buffer[start * req->sectorsize]; + + err = os_seek_file(req->fds[bit], off); + if(err < 0){ + printk("do_io - lseek failed : err = %d\n", -err); + req->error = 1; + return; + } + if(req->op == UBD_READ){ + n = 0; + do { + buf = &buf[n]; + len -= n; + n = os_read_file(req->fds[bit], buf, len); + if (n < 0) { + printk("do_io - read failed, err = %d " + "fd = %d\n", -n, req->fds[bit]); + req->error = 1; + return; + } + } while((n < len) && (n != 0)); + if (n < len) memset(&buf[n], 0, len - n); + } else { + n = os_write_file(req->fds[bit], buf, len); + if(n != len){ + printk("do_io - write failed err = %d " + "fd = %d\n", -n, req->fds[bit]); + req->error = 1; + return; + } + } + + start = end; + } while(start < nsectors); - start = end; - } while(start < nsectors); + req->error = update_bitmap(req); } + +/* Changed in start_io_thread, which is serialized by being called only + * from ubd_init, which is an initcall. + */ +int kernel_fd = -1; + +/* Only changed by the io thread */ +int io_count = 0; + +int io_thread(void *arg) +{ + struct io_thread_req req; + int n; + + ignore_sigwinch_sig(); + while(1){ + n = os_read_file(kernel_fd, &req, sizeof(req)); + if(n != sizeof(req)){ + if(n < 0) + printk("io_thread - read failed, fd = %d, " + "err = %d\n", kernel_fd, -n); + else { + printk("io_thread - short read, fd = %d, " + "length = %d\n", kernel_fd, n); + } + continue; + } + io_count++; + do_io(&req); + n = os_write_file(kernel_fd, &req, sizeof(req)); + if(n != sizeof(req)) + printk("io_thread - write failed, fd = %d, err = %d\n", + kernel_fd, -n); + } +} + +/* + * Overrides for Emacs so that we follow Linus's tabbing style. + * Emacs will notice this stuff at the end of the file and automatically + * adjust the settings for this buffer only. This must remain at the end + * of the file. + * --------------------------------------------------------------------------- + * Local variables: + * c-file-style: "linux" + * End: + */ |