diff options
| -rw-r--r-- | fs/block_dev.c | 2 | ||||
| -rw-r--r-- | fs/pipe.c | 184 | ||||
| -rw-r--r-- | fs/splice.c | 166 | ||||
| -rw-r--r-- | include/linux/pipe_fs_i.h | 29 |
4 files changed, 255 insertions, 126 deletions
diff --git a/fs/block_dev.c b/fs/block_dev.c index af88c43043d5..f5958f413bd1 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -1104,6 +1104,8 @@ const struct file_operations def_blk_fops = { .readv = generic_file_readv, .writev = generic_file_write_nolock, .sendfile = generic_file_sendfile, + .splice_read = generic_file_splice_read, + .splice_write = generic_file_splice_write, }; int ioctl_by_bdev(struct block_device *bdev, unsigned cmd, unsigned long arg) diff --git a/fs/pipe.c b/fs/pipe.c index 7fefb10db8d9..3941a7f78b5d 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -55,7 +55,8 @@ void pipe_wait(struct pipe_inode_info *pipe) } static int -pipe_iov_copy_from_user(void *to, struct iovec *iov, unsigned long len) +pipe_iov_copy_from_user(void *to, struct iovec *iov, unsigned long len, + int atomic) { unsigned long copy; @@ -64,8 +65,13 @@ pipe_iov_copy_from_user(void *to, struct iovec *iov, unsigned long len) iov++; copy = min_t(unsigned long, len, iov->iov_len); - if (copy_from_user(to, iov->iov_base, copy)) - return -EFAULT; + if (atomic) { + if (__copy_from_user_inatomic(to, iov->iov_base, copy)) + return -EFAULT; + } else { + if (copy_from_user(to, iov->iov_base, copy)) + return -EFAULT; + } to += copy; len -= copy; iov->iov_base += copy; @@ -75,7 +81,8 @@ pipe_iov_copy_from_user(void *to, struct iovec *iov, unsigned long len) } static int -pipe_iov_copy_to_user(struct iovec *iov, const void *from, unsigned long len) +pipe_iov_copy_to_user(struct iovec *iov, const void *from, unsigned long len, + int atomic) { unsigned long copy; @@ -84,8 +91,13 @@ pipe_iov_copy_to_user(struct iovec *iov, const void *from, unsigned long len) iov++; copy = min_t(unsigned long, len, iov->iov_len); - if (copy_to_user(iov->iov_base, from, copy)) - return -EFAULT; + if (atomic) { + if (__copy_to_user_inatomic(iov->iov_base, from, copy)) + return -EFAULT; + } else { + if (copy_to_user(iov->iov_base, from, copy)) + return -EFAULT; + } from += copy; len -= copy; iov->iov_base += copy; @@ -94,13 +106,52 @@ pipe_iov_copy_to_user(struct iovec *iov, const void *from, unsigned long len) return 0; } +/* + * Attempt to pre-fault in the user memory, so we can use atomic copies. + * Returns the number of bytes not faulted in. + */ +static int iov_fault_in_pages_write(struct iovec *iov, unsigned long len) +{ + while (!iov->iov_len) + iov++; + + while (len > 0) { + unsigned long this_len; + + this_len = min_t(unsigned long, len, iov->iov_len); + if (fault_in_pages_writeable(iov->iov_base, this_len)) + break; + + len -= this_len; + iov++; + } + + return len; +} + +/* + * Pre-fault in the user memory, so we can use atomic copies. + */ +static void iov_fault_in_pages_read(struct iovec *iov, unsigned long len) +{ + while (!iov->iov_len) + iov++; + + while (len > 0) { + unsigned long this_len; + + this_len = min_t(unsigned long, len, iov->iov_len); + fault_in_pages_readable(iov->iov_base, this_len); + len -= this_len; + iov++; + } +} + static void anon_pipe_buf_release(struct pipe_inode_info *pipe, struct pipe_buffer *buf) { struct page *page = buf->page; - buf->flags &= ~PIPE_BUF_FLAG_STOLEN; - /* * If nobody else uses this page, and we don't already have a * temporary page, let's keep track of it as a one-deep @@ -112,38 +163,58 @@ static void anon_pipe_buf_release(struct pipe_inode_info *pipe, page_cache_release(page); } -static void * anon_pipe_buf_map(struct file *file, struct pipe_inode_info *pipe, - struct pipe_buffer *buf) +void *generic_pipe_buf_map(struct pipe_inode_info *pipe, + struct pipe_buffer *buf, int atomic) { + if (atomic) { + buf->flags |= PIPE_BUF_FLAG_ATOMIC; + return kmap_atomic(buf->page, KM_USER0); + } + return kmap(buf->page); } -static void anon_pipe_buf_unmap(struct pipe_inode_info *pipe, - struct pipe_buffer *buf) +void generic_pipe_buf_unmap(struct pipe_inode_info *pipe, + struct pipe_buffer *buf, void *map_data) { - kunmap(buf->page); + if (buf->flags & PIPE_BUF_FLAG_ATOMIC) { + buf->flags &= ~PIPE_BUF_FLAG_ATOMIC; + kunmap_atomic(map_data, KM_USER0); + } else + kunmap(buf->page); } static int anon_pipe_buf_steal(struct pipe_inode_info *pipe, struct pipe_buffer *buf) { - buf->flags |= PIPE_BUF_FLAG_STOLEN; - return 0; + struct page *page = buf->page; + + if (page_count(page) == 1) { + lock_page(page); + return 0; + } + + return 1; } -static void anon_pipe_buf_get(struct pipe_inode_info *info, - struct pipe_buffer *buf) +void generic_pipe_buf_get(struct pipe_inode_info *info, struct pipe_buffer *buf) { page_cache_get(buf->page); } +int generic_pipe_buf_pin(struct pipe_inode_info *info, struct pipe_buffer *buf) +{ + return 0; +} + static struct pipe_buf_operations anon_pipe_buf_ops = { .can_merge = 1, - .map = anon_pipe_buf_map, - .unmap = anon_pipe_buf_unmap, + .map = generic_pipe_buf_map, + .unmap = generic_pipe_buf_unmap, + .pin = generic_pipe_buf_pin, .release = anon_pipe_buf_release, .steal = anon_pipe_buf_steal, - .get = anon_pipe_buf_get, + .get = generic_pipe_buf_get, }; static ssize_t @@ -174,22 +245,33 @@ pipe_readv(struct file *filp, const struct iovec *_iov, struct pipe_buf_operations *ops = buf->ops; void *addr; size_t chars = buf->len; - int error; + int error, atomic; if (chars > total_len) chars = total_len; - addr = ops->map(filp, pipe, buf); - if (IS_ERR(addr)) { + error = ops->pin(pipe, buf); + if (error) { if (!ret) - ret = PTR_ERR(addr); + error = ret; break; } - error = pipe_iov_copy_to_user(iov, addr + buf->offset, chars); - ops->unmap(pipe, buf); + + atomic = !iov_fault_in_pages_write(iov, chars); +redo: + addr = ops->map(pipe, buf, atomic); + error = pipe_iov_copy_to_user(iov, addr + buf->offset, chars, atomic); + ops->unmap(pipe, buf, addr); if (unlikely(error)) { + /* + * Just retry with the slow path if we failed. + */ + if (atomic) { + atomic = 0; + goto redo; + } if (!ret) - ret = -EFAULT; + ret = error; break; } ret += chars; @@ -293,21 +375,28 @@ pipe_writev(struct file *filp, const struct iovec *_iov, int offset = buf->offset + buf->len; if (ops->can_merge && offset + chars <= PAGE_SIZE) { + int error, atomic = 1; void *addr; - int error; - addr = ops->map(filp, pipe, buf); - if (IS_ERR(addr)) { - error = PTR_ERR(addr); + error = ops->pin(pipe, buf); + if (error) goto out; - } + + iov_fault_in_pages_read(iov, chars); +redo1: + addr = ops->map(pipe, buf, atomic); error = pipe_iov_copy_from_user(offset + addr, iov, - chars); - ops->unmap(pipe, buf); + chars, atomic); + ops->unmap(pipe, buf, addr); ret = error; do_wakeup = 1; - if (error) + if (error) { + if (atomic) { + atomic = 0; + goto redo1; + } goto out; + } buf->len += chars; total_len -= chars; ret = chars; @@ -330,7 +419,8 @@ pipe_writev(struct file *filp, const struct iovec *_iov, int newbuf = (pipe->curbuf + bufs) & (PIPE_BUFFERS-1); struct pipe_buffer *buf = pipe->bufs + newbuf; struct page *page = pipe->tmp_page; - int error; + char *src; + int error, atomic = 1; if (!page) { page = alloc_page(GFP_HIGHUSER); @@ -350,11 +440,27 @@ pipe_writev(struct file *filp, const struct iovec *_iov, if (chars > total_len) chars = total_len; - error = pipe_iov_copy_from_user(kmap(page), iov, chars); - kunmap(page); + iov_fault_in_pages_read(iov, chars); +redo2: + if (atomic) + src = kmap_atomic(page, KM_USER0); + else + src = kmap(page); + + error = pipe_iov_copy_from_user(src, iov, chars, + atomic); + if (atomic) + kunmap_atomic(src, KM_USER0); + else + kunmap(page); + if (unlikely(error)) { + if (atomic) { + atomic = 0; + goto redo2; + } if (!ret) - ret = -EFAULT; + ret = error; break; } ret += chars; diff --git a/fs/splice.c b/fs/splice.c index a46ddd28561e..b150493b6fc3 100644 --- a/fs/splice.c +++ b/fs/splice.c @@ -78,7 +78,7 @@ static int page_cache_pipe_buf_steal(struct pipe_inode_info *info, return 1; } - buf->flags |= PIPE_BUF_FLAG_STOLEN | PIPE_BUF_FLAG_LRU; + buf->flags |= PIPE_BUF_FLAG_LRU; return 0; } @@ -87,12 +87,11 @@ static void page_cache_pipe_buf_release(struct pipe_inode_info *info, { page_cache_release(buf->page); buf->page = NULL; - buf->flags &= ~(PIPE_BUF_FLAG_STOLEN | PIPE_BUF_FLAG_LRU); + buf->flags &= ~PIPE_BUF_FLAG_LRU; } -static void *page_cache_pipe_buf_map(struct file *file, - struct pipe_inode_info *info, - struct pipe_buffer *buf) +static int page_cache_pipe_buf_pin(struct pipe_inode_info *info, + struct pipe_buffer *buf) { struct page *page = buf->page; int err; @@ -118,64 +117,44 @@ static void *page_cache_pipe_buf_map(struct file *file, } /* - * Page is ok afterall, fall through to mapping. + * Page is ok afterall, we are done. */ unlock_page(page); } - return kmap(page); + return 0; error: unlock_page(page); - return ERR_PTR(err); -} - -static void page_cache_pipe_buf_unmap(struct pipe_inode_info *info, - struct pipe_buffer *buf) -{ - kunmap(buf->page); -} - -static void *user_page_pipe_buf_map(struct file *file, - struct pipe_inode_info *pipe, - struct pipe_buffer *buf) -{ - return kmap(buf->page); -} - -static void user_page_pipe_buf_unmap(struct pipe_inode_info *pipe, - struct pipe_buffer *buf) -{ - kunmap(buf->page); -} - -static void page_cache_pipe_buf_get(struct pipe_inode_info *info, - struct pipe_buffer *buf) -{ - page_cache_get(buf->page); + return err; } static struct pipe_buf_operations page_cache_pipe_buf_ops = { .can_merge = 0, - .map = page_cache_pipe_buf_map, - .unmap = page_cache_pipe_buf_unmap, + .map = generic_pipe_buf_map, + .unmap = generic_pipe_buf_unmap, + .pin = page_cache_pipe_buf_pin, .release = page_cache_pipe_buf_release, .steal = page_cache_pipe_buf_steal, - .get = page_cache_pipe_buf_get, + .get = generic_pipe_buf_get, }; static int user_page_pipe_buf_steal(struct pipe_inode_info *pipe, struct pipe_buffer *buf) { - return 1; + if (!(buf->flags & PIPE_BUF_FLAG_GIFT)) + return 1; + + return 0; } static struct pipe_buf_operations user_page_pipe_buf_ops = { .can_merge = 0, - .map = user_page_pipe_buf_map, - .unmap = user_page_pipe_buf_unmap, + .map = generic_pipe_buf_map, + .unmap = generic_pipe_buf_unmap, + .pin = generic_pipe_buf_pin, .release = page_cache_pipe_buf_release, .steal = user_page_pipe_buf_steal, - .get = page_cache_pipe_buf_get, + .get = generic_pipe_buf_get, }; /* @@ -210,6 +189,9 @@ static ssize_t splice_to_pipe(struct pipe_inode_info *pipe, buf->offset = spd->partial[page_nr].offset; buf->len = spd->partial[page_nr].len; buf->ops = spd->ops; + if (spd->flags & SPLICE_F_GIFT) + buf->flags |= PIPE_BUF_FLAG_GIFT; + pipe->nrbufs++; page_nr++; ret += buf->len; @@ -326,6 +308,12 @@ __generic_file_splice_read(struct file *in, loff_t *ppos, page = find_get_page(mapping, index); if (!page) { /* + * Make sure the read-ahead engine is notified + * about this failure. + */ + handle_ra_miss(mapping, &in->f_ra, index); + + /* * page didn't exist, allocate one. */ page = page_cache_alloc_cold(mapping); @@ -517,26 +505,16 @@ static int pipe_to_sendpage(struct pipe_inode_info *info, { struct file *file = sd->file; loff_t pos = sd->pos; - ssize_t ret; - void *ptr; - int more; - - /* - * Sub-optimal, but we are limited by the pipe ->map. We don't - * need a kmap'ed buffer here, we just want to make sure we - * have the page pinned if the pipe page originates from the - * page cache. - */ - ptr = buf->ops->map(file, info, buf); - if (IS_ERR(ptr)) - return PTR_ERR(ptr); + int ret, more; - more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len; + ret = buf->ops->pin(info, buf); + if (!ret) { + more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len; - ret = file->f_op->sendpage(file, buf->page, buf->offset, sd->len, - &pos, more); + ret = file->f_op->sendpage(file, buf->page, buf->offset, + sd->len, &pos, more); + } - buf->ops->unmap(info, buf); return ret; } @@ -569,15 +547,14 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf, unsigned int offset, this_len; struct page *page; pgoff_t index; - char *src; int ret; /* * make sure the data in this buffer is uptodate */ - src = buf->ops->map(file, info, buf); - if (IS_ERR(src)) - return PTR_ERR(src); + ret = buf->ops->pin(info, buf); + if (unlikely(ret)) + return ret; index = sd->pos >> PAGE_CACHE_SHIFT; offset = sd->pos & ~PAGE_CACHE_MASK; @@ -587,9 +564,10 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf, this_len = PAGE_CACHE_SIZE - offset; /* - * Reuse buf page, if SPLICE_F_MOVE is set. + * Reuse buf page, if SPLICE_F_MOVE is set and we are doing a full + * page. */ - if (sd->flags & SPLICE_F_MOVE) { + if ((sd->flags & SPLICE_F_MOVE) && this_len == PAGE_CACHE_SIZE) { /* * If steal succeeds, buf->page is now pruned from the vm * side (LRU and page cache) and we can reuse it. The page @@ -599,8 +577,12 @@ static int pipe_to_file(struct pipe_inode_info *info, struct pipe_buffer *buf, goto find_page; page = buf->page; - if (add_to_page_cache(page, mapping, index, gfp_mask)) + if (add_to_page_cache(page, mapping, index, gfp_mask)) { + unlock_page(page); goto find_page; + } + + page_cache_get(page); if (!(buf->flags & PIPE_BUF_FLAG_LRU)) lru_cache_add(page); @@ -660,34 +642,36 @@ find_page: } else if (ret) goto out; - if (!(buf->flags & PIPE_BUF_FLAG_STOLEN)) { - char *dst = kmap_atomic(page, KM_USER0); + if (buf->page != page) { + /* + * Careful, ->map() uses KM_USER0! + */ + char *src = buf->ops->map(info, buf, 1); + char *dst = kmap_atomic(page, KM_USER1); memcpy(dst + offset, src + buf->offset, this_len); flush_dcache_page(page); - kunmap_atomic(dst, KM_USER0); + kunmap_atomic(dst, KM_USER1); + buf->ops->unmap(info, buf, src); } ret = mapping->a_ops->commit_write(file, page, offset, offset+this_len); - if (ret == AOP_TRUNCATED_PAGE) { + if (!ret) { + /* + * Return the number of bytes written and mark page as + * accessed, we are now done! + */ + ret = this_len; + mark_page_accessed(page); + balance_dirty_pages_ratelimited(mapping); + } else if (ret == AOP_TRUNCATED_PAGE) { page_cache_release(page); goto find_page; - } else if (ret) - goto out; - - /* - * Return the number of bytes written. - */ - ret = this_len; - mark_page_accessed(page); - balance_dirty_pages_ratelimited(mapping); + } out: - if (!(buf->flags & PIPE_BUF_FLAG_STOLEN)) - page_cache_release(page); - + page_cache_release(page); unlock_page(page); out_nomem: - buf->ops->unmap(info, buf); return ret; } @@ -1095,7 +1079,7 @@ static long do_splice(struct file *in, loff_t __user *off_in, */ static int get_iovec_page_array(const struct iovec __user *iov, unsigned int nr_vecs, struct page **pages, - struct partial_page *partial) + struct partial_page *partial, int aligned) { int buffers = 0, error = 0; @@ -1135,6 +1119,15 @@ static int get_iovec_page_array(const struct iovec __user *iov, * in the user pages. */ off = (unsigned long) base & ~PAGE_MASK; + + /* + * If asked for alignment, the offset must be zero and the + * length a multiple of the PAGE_SIZE. + */ + error = -EINVAL; + if (aligned && (off || len & ~PAGE_MASK)) + break; + npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT; if (npages > PIPE_BUFFERS - buffers) npages = PIPE_BUFFERS - buffers; @@ -1228,7 +1221,8 @@ static long do_vmsplice(struct file *file, const struct iovec __user *iov, else if (unlikely(!nr_segs)) return 0; - spd.nr_pages = get_iovec_page_array(iov, nr_segs, pages, partial); + spd.nr_pages = get_iovec_page_array(iov, nr_segs, pages, partial, + flags & SPLICE_F_GIFT); if (spd.nr_pages <= 0) return spd.nr_pages; @@ -1336,6 +1330,12 @@ static int link_pipe(struct pipe_inode_info *ipipe, obuf = opipe->bufs + nbuf; *obuf = *ibuf; + /* + * Don't inherit the gift flag, we need to + * prevent multiple steals of this page. + */ + obuf->flags &= ~PIPE_BUF_FLAG_GIFT; + if (obuf->len > len) obuf->len = len; diff --git a/include/linux/pipe_fs_i.h b/include/linux/pipe_fs_i.h index 0008d4bd4059..df4d3fa7d3dc 100644 --- a/include/linux/pipe_fs_i.h +++ b/include/linux/pipe_fs_i.h @@ -5,8 +5,9 @@ #define PIPE_BUFFERS (16) -#define PIPE_BUF_FLAG_STOLEN 0x01 -#define PIPE_BUF_FLAG_LRU 0x02 +#define PIPE_BUF_FLAG_LRU 0x01 /* page is on the LRU */ +#define PIPE_BUF_FLAG_ATOMIC 0x02 /* was atomically mapped */ +#define PIPE_BUF_FLAG_GIFT 0x04 /* page is a gift */ struct pipe_buffer { struct page *page; @@ -15,10 +16,23 @@ struct pipe_buffer { unsigned int flags; }; +/* + * Note on the nesting of these functions: + * + * ->pin() + * ->steal() + * ... + * ->map() + * ... + * ->unmap() + * + * That is, ->map() must be called on a pinned buffer, same goes for ->steal(). + */ struct pipe_buf_operations { int can_merge; - void * (*map)(struct file *, struct pipe_inode_info *, struct pipe_buffer *); - void (*unmap)(struct pipe_inode_info *, struct pipe_buffer *); + void * (*map)(struct pipe_inode_info *, struct pipe_buffer *, int); + void (*unmap)(struct pipe_inode_info *, struct pipe_buffer *, void *); + int (*pin)(struct pipe_inode_info *, struct pipe_buffer *); void (*release)(struct pipe_inode_info *, struct pipe_buffer *); int (*steal)(struct pipe_inode_info *, struct pipe_buffer *); void (*get)(struct pipe_inode_info *, struct pipe_buffer *); @@ -51,6 +65,12 @@ struct pipe_inode_info * alloc_pipe_info(struct inode * inode); void free_pipe_info(struct inode * inode); void __free_pipe_info(struct pipe_inode_info *); +/* Generic pipe buffer ops functions */ +void *generic_pipe_buf_map(struct pipe_inode_info *, struct pipe_buffer *, int); +void generic_pipe_buf_unmap(struct pipe_inode_info *, struct pipe_buffer *, void *); +void generic_pipe_buf_get(struct pipe_inode_info *, struct pipe_buffer *); +int generic_pipe_buf_pin(struct pipe_inode_info *, struct pipe_buffer *); + /* * splice is tied to pipes as a transport (at least for now), so we'll just * add the splice flags here. @@ -60,6 +80,7 @@ void __free_pipe_info(struct pipe_inode_info *); /* we may still block on the fd we splice */ /* from/to, of course */ #define SPLICE_F_MORE (0x04) /* expect more data */ +#define SPLICE_F_GIFT (0x08) /* pages passed in are a gift */ /* * Passed to the actors |