From: Jeff Dike Date: Fri, 20 May 2005 20:59:11 +0000 (-0700) Subject: [PATCH] uml: Remove ubd-mmap support X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=7b9014c1da380384efe7752db38a0253a74d0238;p=openwrt%2Fstaging%2Fblogic.git [PATCH] uml: Remove ubd-mmap support Finally rip out the ubd-mmap code, which turned out to be broken by design. Signed-off-by: Jeff Dike Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c index 9a56ff94308d..88f956c34fed 100644 --- a/arch/um/drivers/ubd_kern.c +++ b/arch/um/drivers/ubd_kern.c @@ -55,7 +55,7 @@ #include "mem_kern.h" #include "cow.h" -enum ubd_req { UBD_READ, UBD_WRITE, UBD_MMAP }; +enum ubd_req { UBD_READ, UBD_WRITE }; struct io_thread_req { enum ubd_req op; @@ -68,8 +68,6 @@ struct io_thread_req { unsigned long sector_mask; unsigned long long cow_offset; unsigned long bitmap_words[2]; - int map_fd; - unsigned long long map_offset; int error; }; @@ -122,10 +120,6 @@ static int ubd_ioctl(struct inode * inode, struct file * file, #define MAX_DEV (8) -/* Changed in early boot */ -static int ubd_do_mmap = 0; -#define UBD_MMAP_BLOCK_SIZE PAGE_SIZE - static struct block_device_operations ubd_blops = { .owner = THIS_MODULE, .open = ubd_open, @@ -175,12 +169,6 @@ struct ubd { int no_cow; struct cow cow; struct platform_device pdev; - - int map_writes; - int map_reads; - int nomap_writes; - int nomap_reads; - int write_maps; }; #define DEFAULT_COW { \ @@ -200,11 +188,6 @@ struct ubd { .openflags = OPEN_FLAGS, \ .no_cow = 0, \ .cow = DEFAULT_COW, \ - .map_writes = 0, \ - .map_reads = 0, \ - .nomap_writes = 0, \ - .nomap_reads = 0, \ - .write_maps = 0, \ } struct ubd ubd_dev[MAX_DEV] = { [ 0 ... MAX_DEV - 1 ] = DEFAULT_UBD }; @@ -314,13 +297,6 @@ static int ubd_setup_common(char *str, int *index_out) int major; str++; - if(!strcmp(str, "mmap")){ - CHOOSE_MODE(printk("mmap not supported by the ubd " - "driver in tt mode\n"), - ubd_do_mmap = 1); - return(0); - } - if(!strcmp(str, "sync")){ global_openflags = of_sync(global_openflags); return(0); @@ -524,7 +500,7 @@ static void ubd_handler(void) { struct io_thread_req req; struct request *rq = elv_next_request(ubd_queue); - int n, err; + int n; do_ubd = NULL; intr_count++; @@ -538,19 +514,6 @@ static void ubd_handler(void) return; } - if((req.op != UBD_MMAP) && - ((req.offset != ((__u64) (rq->sector)) << 9) || - (req.length != (rq->current_nr_sectors) << 9))) - panic("I/O op mismatch"); - - if(req.map_fd != -1){ - err = physmem_subst_mapping(req.buffer, req.map_fd, - req.map_offset, 1); - if(err) - printk("ubd_handler - physmem_subst_mapping failed, " - "err = %d\n", -err); - } - ubd_finish(rq, req.error); reactivate_fd(thread_fd, UBD_IRQ); do_ubd_request(ubd_queue); @@ -583,14 +546,10 @@ static int ubd_file_size(struct ubd *dev, __u64 *size_out) static void ubd_close(struct ubd *dev) { - if(ubd_do_mmap) - physmem_forget_descriptor(dev->fd); os_close_file(dev->fd); if(dev->cow.file == NULL) return; - if(ubd_do_mmap) - physmem_forget_descriptor(dev->cow.fd); os_close_file(dev->cow.fd); vfree(dev->cow.bitmap); dev->cow.bitmap = NULL; @@ -1010,94 +969,13 @@ static void cowify_req(struct io_thread_req *req, unsigned long *bitmap, req->bitmap_words, bitmap_len); } -static int mmap_fd(struct request *req, struct ubd *dev, __u64 offset) -{ - __u64 sector; - unsigned char *bitmap; - int bit, i; - - /* mmap must have been requested on the command line */ - if(!ubd_do_mmap) - return(-1); - - /* The buffer must be page aligned */ - if(((unsigned long) req->buffer % UBD_MMAP_BLOCK_SIZE) != 0) - return(-1); - - /* The request must be a page long */ - if((req->current_nr_sectors << 9) != PAGE_SIZE) - return(-1); - - if(dev->cow.file == NULL) - return(dev->fd); - - sector = offset >> 9; - bitmap = (unsigned char *) dev->cow.bitmap; - bit = ubd_test_bit(sector, bitmap); - - for(i = 1; i < req->current_nr_sectors; i++){ - if(ubd_test_bit(sector + i, bitmap) != bit) - return(-1); - } - - if(bit || (rq_data_dir(req) == WRITE)) - offset += dev->cow.data_offset; - - /* The data on disk must be page aligned */ - if((offset % UBD_MMAP_BLOCK_SIZE) != 0) - return(-1); - - return(bit ? dev->fd : dev->cow.fd); -} - -static int prepare_mmap_request(struct ubd *dev, int fd, __u64 offset, - struct request *req, - struct io_thread_req *io_req) -{ - int err; - - if(rq_data_dir(req) == WRITE){ - /* Writes are almost no-ops since the new data is already in the - * host page cache - */ - dev->map_writes++; - if(dev->cow.file != NULL) - cowify_bitmap(io_req->offset, io_req->length, - &io_req->sector_mask, &io_req->cow_offset, - dev->cow.bitmap, dev->cow.bitmap_offset, - io_req->bitmap_words, - dev->cow.bitmap_len); - } - else { - int w; - - if((dev->cow.file != NULL) && (fd == dev->cow.fd)) - w = 0; - else w = dev->openflags.w; - - if((dev->cow.file != NULL) && (fd == dev->fd)) - offset += dev->cow.data_offset; - - err = physmem_subst_mapping(req->buffer, fd, offset, w); - if(err){ - printk("physmem_subst_mapping failed, err = %d\n", - -err); - return(1); - } - dev->map_reads++; - } - io_req->op = UBD_MMAP; - io_req->buffer = req->buffer; - return(0); -} - /* Called with ubd_io_lock held */ 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, fd; + int len; if(req->rq_status == RQ_INACTIVE) return(1); @@ -1114,34 +992,12 @@ static int prepare_request(struct request *req, struct io_thread_req *io_req) io_req->fds[0] = (dev->cow.file != NULL) ? dev->cow.fd : dev->fd; io_req->fds[1] = dev->fd; - io_req->map_fd = -1; io_req->cow_offset = -1; io_req->offset = offset; io_req->length = len; io_req->error = 0; io_req->sector_mask = 0; - fd = mmap_fd(req, dev, io_req->offset); - if(fd > 0){ - /* If mmapping is otherwise OK, but the first access to the - * page is a write, then it's not mapped in yet. So we have - * to write the data to disk first, then we can map the disk - * page in and continue normally from there. - */ - if((rq_data_dir(req) == WRITE) && !is_remapped(req->buffer)){ - io_req->map_fd = dev->fd; - io_req->map_offset = io_req->offset + - dev->cow.data_offset; - dev->write_maps++; - } - else return(prepare_mmap_request(dev, fd, io_req->offset, req, - io_req)); - } - - if(rq_data_dir(req) == READ) - dev->nomap_reads++; - else dev->nomap_writes++; - 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; @@ -1229,143 +1085,6 @@ static int ubd_ioctl(struct inode * inode, struct file * file, return(-EINVAL); } -static int ubd_check_remapped(int fd, unsigned long address, int is_write, - __u64 offset) -{ - __u64 bitmap_offset; - unsigned long new_bitmap[2]; - int i, err, n; - - /* If it's not a write access, we can't do anything about it */ - if(!is_write) - return(0); - - /* We have a write */ - for(i = 0; i < sizeof(ubd_dev) / sizeof(ubd_dev[0]); i++){ - struct ubd *dev = &ubd_dev[i]; - - if((dev->fd != fd) && (dev->cow.fd != fd)) - continue; - - /* It's a write to a ubd device */ - - /* This should be impossible now */ - if(!dev->openflags.w){ - /* It's a write access on a read-only device - probably - * shouldn't happen. If the kernel is trying to change - * something with no intention of writing it back out, - * then this message will clue us in that this needs - * fixing - */ - printk("Write access to mapped page from readonly ubd " - "device %d\n", i); - return(0); - } - - /* It's a write to a writeable ubd device - it must be COWed - * because, otherwise, the page would have been mapped in - * writeable - */ - - if(!dev->cow.file) - panic("Write fault on writeable non-COW ubd device %d", - i); - - /* It should also be an access to the backing file since the - * COW pages should be mapped in read-write - */ - - if(fd == dev->fd) - panic("Write fault on a backing page of ubd " - "device %d\n", i); - - /* So, we do the write, copying the backing data to the COW - * file... - */ - - err = os_seek_file(dev->fd, offset + dev->cow.data_offset); - if(err < 0) - panic("Couldn't seek to %lld in COW file of ubd " - "device %d, err = %d", - offset + dev->cow.data_offset, i, -err); - - n = os_write_file(dev->fd, (void *) address, PAGE_SIZE); - if(n != PAGE_SIZE) - panic("Couldn't copy data to COW file of ubd " - "device %d, err = %d", i, -n); - - /* ... updating the COW bitmap... */ - - cowify_bitmap(offset, PAGE_SIZE, NULL, &bitmap_offset, - dev->cow.bitmap, dev->cow.bitmap_offset, - new_bitmap, dev->cow.bitmap_len); - - err = os_seek_file(dev->fd, bitmap_offset); - if(err < 0) - panic("Couldn't seek to %lld in COW file of ubd " - "device %d, err = %d", bitmap_offset, i, -err); - - n = os_write_file(dev->fd, new_bitmap, sizeof(new_bitmap)); - if(n != sizeof(new_bitmap)) - panic("Couldn't update bitmap of ubd device %d, " - "err = %d", i, -n); - - /* Maybe we can map the COW page in, and maybe we can't. If - * it is a pre-V3 COW file, we can't, since the alignment will - * be wrong. If it is a V3 or later COW file which has been - * moved to a system with a larger page size, then maybe we - * can't, depending on the exact location of the page. - */ - - offset += dev->cow.data_offset; - - /* Remove the remapping, putting the original anonymous page - * back. If the COW file can be mapped in, that is done. - * Otherwise, the COW page is read in. - */ - - if(!physmem_remove_mapping((void *) address)) - panic("Address 0x%lx not remapped by ubd device %d", - address, i); - if((offset % UBD_MMAP_BLOCK_SIZE) == 0) - physmem_subst_mapping((void *) address, dev->fd, - offset, 1); - else { - err = os_seek_file(dev->fd, offset); - if(err < 0) - panic("Couldn't seek to %lld in COW file of " - "ubd device %d, err = %d", offset, i, - -err); - - n = os_read_file(dev->fd, (void *) address, PAGE_SIZE); - if(n != PAGE_SIZE) - panic("Failed to read page from offset %llx of " - "COW file of ubd device %d, err = %d", - offset, i, -n); - } - - return(1); - } - - /* It's not a write on a ubd device */ - return(0); -} - -static struct remapper ubd_remapper = { - .list = LIST_HEAD_INIT(ubd_remapper.list), - .proc = ubd_check_remapped, -}; - -static int ubd_remapper_setup(void) -{ - if(ubd_do_mmap) - register_remapper(&ubd_remapper); - - return(0); -} - -__initcall(ubd_remapper_setup); - static int same_backing_files(char *from_cmdline, char *from_cow, char *cow) { struct uml_stat buf1, buf2; @@ -1568,15 +1287,6 @@ void do_io(struct io_thread_req *req) int err; __u64 off; - if(req->op == UBD_MMAP){ - /* Touch the page to force the host to do any necessary IO to - * get it into memory - */ - n = *((volatile int *) req->buffer); - req->error = update_bitmap(req); - return; - } - nsectors = req->length / req->sectorsize; start = 0; do { diff --git a/arch/um/kernel/trap_kern.c b/arch/um/kernel/trap_kern.c index 9ae2eff0d8f3..1de22d8a313a 100644 --- a/arch/um/kernel/trap_kern.c +++ b/arch/um/kernel/trap_kern.c @@ -107,33 +107,6 @@ out_of_memory: goto out; } -LIST_HEAD(physmem_remappers); - -void register_remapper(struct remapper *info) -{ - list_add(&info->list, &physmem_remappers); -} - -static int check_remapped_addr(unsigned long address, int is_write) -{ - struct remapper *remapper; - struct list_head *ele; - __u64 offset; - int fd; - - fd = phys_mapping(__pa(address), &offset); - if(fd == -1) - return(0); - - list_for_each(ele, &physmem_remappers){ - remapper = list_entry(ele, struct remapper, list); - if((*remapper->proc)(fd, address, is_write, offset)) - return(1); - } - - return(0); -} - /* * We give a *copy* of the faultinfo in the regs to segv. * This must be done, since nesting SEGVs could overwrite @@ -152,8 +125,6 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user, void *sc) flush_tlb_kernel_vm(); return(0); } - else if(check_remapped_addr(address & PAGE_MASK, is_write)) - return(0); else if(current->mm == NULL) panic("Segfault with no mm"); err = handle_page_fault(address, ip, is_write, is_user, &si.si_code);