From: Al Viro Date: Fri, 21 Mar 2014 08:58:33 +0000 (-0400) Subject: new helper: iov_iter_get_pages_alloc() X-Git-Tag: v4.9.8~6259^2~49 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=91f79c43d1b54d7154b118860d81b39bad07dfff;p=platform%2Fkernel%2Flinux-rpi3.git new helper: iov_iter_get_pages_alloc() same as iov_iter_get_pages(), except that pages array is allocated (kmalloc if possible, vmalloc if that fails) and left for caller to free. Lustre and NFS ->direct_IO() switched to it. Signed-off-by: Al Viro --- diff --git a/drivers/staging/lustre/lustre/llite/rw26.c b/drivers/staging/lustre/lustre/llite/rw26.c index f718585..6b59945 100644 --- a/drivers/staging/lustre/lustre/llite/rw26.c +++ b/drivers/staging/lustre/lustre/llite/rw26.c @@ -218,14 +218,11 @@ static void ll_free_user_pages(struct page **pages, int npages, int do_dirty) int i; for (i = 0; i < npages; i++) { - if (pages[i] == NULL) - break; if (do_dirty) set_page_dirty_lock(pages[i]); page_cache_release(pages[i]); } - - OBD_FREE_LARGE(pages, npages * sizeof(*pages)); + kvfree(pages); } ssize_t ll_direct_rw_pages(const struct lu_env *env, struct cl_io *io, @@ -370,10 +367,9 @@ static ssize_t ll_direct_IO_26(int rw, struct kiocb *iocb, struct file *file = iocb->ki_filp; struct inode *inode = file->f_mapping->host; struct ccc_object *obj = cl_inode2ccc(inode); - long count = iov_iter_count(iter); - long tot_bytes = 0, result = 0; + ssize_t count = iov_iter_count(iter); + ssize_t tot_bytes = 0, result = 0; struct ll_inode_info *lli = ll_i2info(inode); - unsigned long seg = 0; long size = MAX_DIO_SIZE; int refcheck; @@ -407,63 +403,49 @@ static ssize_t ll_direct_IO_26(int rw, struct kiocb *iocb, mutex_lock(&inode->i_mutex); LASSERT(obj->cob_transient_pages == 0); - for (seg = 0; seg < iter->nr_segs; seg++) { - long iov_left = iter->iov[seg].iov_len; - unsigned long user_addr = (unsigned long)iter->iov[seg].iov_base; + while (iov_iter_count(iter)) { + struct page **pages; + size_t offs; + count = min_t(size_t, iov_iter_count(iter), size); if (rw == READ) { if (file_offset >= i_size_read(inode)) break; - if (file_offset + iov_left > i_size_read(inode)) - iov_left = i_size_read(inode) - file_offset; + if (file_offset + count > i_size_read(inode)) + count = i_size_read(inode) - file_offset; } - while (iov_left > 0) { - struct page **pages; - int page_count, max_pages = 0; - long bytes; - - bytes = min(size, iov_left); - page_count = ll_get_user_pages(rw, user_addr, bytes, - &pages, &max_pages); - if (likely(page_count > 0)) { - if (unlikely(page_count < max_pages)) - bytes = page_count << PAGE_CACHE_SHIFT; - result = ll_direct_IO_26_seg(env, io, rw, inode, - file->f_mapping, - bytes, file_offset, - pages, page_count); - ll_free_user_pages(pages, max_pages, rw==READ); - } else if (page_count == 0) { - GOTO(out, result = -EFAULT); - } else { - result = page_count; - } - if (unlikely(result <= 0)) { - /* If we can't allocate a large enough buffer - * for the request, shrink it to a smaller - * PAGE_SIZE multiple and try again. - * We should always be able to kmalloc for a - * page worth of page pointers = 4MB on i386. */ - if (result == -ENOMEM && - size > (PAGE_CACHE_SIZE / sizeof(*pages)) * - PAGE_CACHE_SIZE) { - size = ((((size / 2) - 1) | - ~CFS_PAGE_MASK) + 1) & - CFS_PAGE_MASK; - CDEBUG(D_VFSTRACE,"DIO size now %lu\n", - size); - continue; - } - - GOTO(out, result); + result = iov_iter_get_pages_alloc(iter, &pages, count, &offs); + if (likely(result > 0)) { + int n = (result + offs + PAGE_SIZE - 1) / PAGE_SIZE; + result = ll_direct_IO_26_seg(env, io, rw, inode, + file->f_mapping, + result, file_offset, + pages, n); + ll_free_user_pages(pages, n, rw==READ); + } + if (unlikely(result <= 0)) { + /* If we can't allocate a large enough buffer + * for the request, shrink it to a smaller + * PAGE_SIZE multiple and try again. + * We should always be able to kmalloc for a + * page worth of page pointers = 4MB on i386. */ + if (result == -ENOMEM && + size > (PAGE_CACHE_SIZE / sizeof(*pages)) * + PAGE_CACHE_SIZE) { + size = ((((size / 2) - 1) | + ~CFS_PAGE_MASK) + 1) & + CFS_PAGE_MASK; + CDEBUG(D_VFSTRACE,"DIO size now %lu\n", + size); + continue; } - tot_bytes += result; - file_offset += result; - iov_left -= result; - user_addr += result; + GOTO(out, result); } + iov_iter_advance(iter, result); + tot_bytes += result; + file_offset += result; } out: LASSERT(obj->cob_transient_pages == 0); diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c index 1d34f45..b122fe2 100644 --- a/fs/nfs/direct.c +++ b/fs/nfs/direct.c @@ -322,60 +322,37 @@ static const struct nfs_pgio_completion_ops nfs_direct_read_completion_ops = { * handled automatically by nfs_direct_read_result(). Otherwise, if * no requests have been sent, just return an error. */ -static ssize_t nfs_direct_read_schedule_segment(struct nfs_pageio_descriptor *desc, - const struct iovec *iov, - loff_t pos, bool uio) -{ - struct nfs_direct_req *dreq = desc->pg_dreq; - struct nfs_open_context *ctx = dreq->ctx; - struct inode *inode = ctx->dentry->d_inode; - unsigned long user_addr = (unsigned long)iov->iov_base; - size_t count = iov->iov_len; - size_t rsize = NFS_SERVER(inode)->rsize; - unsigned int pgbase; - int result; - ssize_t started = 0; - struct page **pagevec = NULL; - unsigned int npages; - - do { - size_t bytes; - int i; - pgbase = user_addr & ~PAGE_MASK; - bytes = min(max_t(size_t, rsize, PAGE_SIZE), count); +static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq, + struct iov_iter *iter, + loff_t pos) +{ + struct nfs_pageio_descriptor desc; + struct inode *inode = dreq->inode; + ssize_t result = -EINVAL; + size_t requested_bytes = 0; + size_t rsize = max_t(size_t, NFS_SERVER(inode)->rsize, PAGE_SIZE); - result = -ENOMEM; - npages = nfs_page_array_len(pgbase, bytes); - if (!pagevec) - pagevec = kmalloc(npages * sizeof(struct page *), - GFP_KERNEL); - if (!pagevec) - break; - if (uio) { - down_read(¤t->mm->mmap_sem); - result = get_user_pages(current, current->mm, user_addr, - npages, 1, 0, pagevec, NULL); - up_read(¤t->mm->mmap_sem); - if (result < 0) - break; - } else { - WARN_ON(npages != 1); - result = get_kernel_page(user_addr, 1, pagevec); - if (WARN_ON(result != 1)) - break; - } + NFS_PROTO(dreq->inode)->read_pageio_init(&desc, dreq->inode, + &nfs_direct_read_completion_ops); + get_dreq(dreq); + desc.pg_dreq = dreq; + atomic_inc(&inode->i_dio_count); - if ((unsigned)result < npages) { - bytes = result * PAGE_SIZE; - if (bytes <= pgbase) { - nfs_direct_release_pages(pagevec, result); - break; - } - bytes -= pgbase; - npages = result; - } + while (iov_iter_count(iter)) { + struct page **pagevec; + size_t bytes; + size_t pgbase; + unsigned npages, i; + result = iov_iter_get_pages_alloc(iter, &pagevec, + rsize, &pgbase); + if (result < 0) + break; + + bytes = result; + iov_iter_advance(iter, bytes); + npages = (result + pgbase + PAGE_SIZE - 1) / PAGE_SIZE; for (i = 0; i < npages; i++) { struct nfs_page *req; unsigned int req_len = min_t(size_t, bytes, PAGE_SIZE - pgbase); @@ -389,55 +366,21 @@ static ssize_t nfs_direct_read_schedule_segment(struct nfs_pageio_descriptor *de } req->wb_index = pos >> PAGE_SHIFT; req->wb_offset = pos & ~PAGE_MASK; - if (!nfs_pageio_add_request(desc, req)) { - result = desc->pg_error; + if (!nfs_pageio_add_request(&desc, req)) { + result = desc.pg_error; nfs_release_request(req); break; } pgbase = 0; bytes -= req_len; - started += req_len; - user_addr += req_len; + requested_bytes += req_len; pos += req_len; - count -= req_len; dreq->bytes_left -= req_len; } - /* The nfs_page now hold references to these pages */ nfs_direct_release_pages(pagevec, npages); - } while (count != 0 && result >= 0); - - kfree(pagevec); - - if (started) - return started; - return result < 0 ? (ssize_t) result : -EFAULT; -} - -static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq, - struct iov_iter *iter, - loff_t pos, bool uio) -{ - struct nfs_pageio_descriptor desc; - struct inode *inode = dreq->inode; - ssize_t result = -EINVAL; - size_t requested_bytes = 0; - unsigned long seg; - - NFS_PROTO(dreq->inode)->read_pageio_init(&desc, dreq->inode, - &nfs_direct_read_completion_ops); - get_dreq(dreq); - desc.pg_dreq = dreq; - atomic_inc(&inode->i_dio_count); - - for (seg = 0; seg < iter->nr_segs; seg++) { - const struct iovec *vec = &iter->iov[seg]; - result = nfs_direct_read_schedule_segment(&desc, vec, pos, uio); + kvfree(pagevec); if (result < 0) break; - requested_bytes += result; - if ((size_t)result < vec->iov_len) - break; - pos += vec->iov_len; } nfs_pageio_complete(&desc); @@ -521,7 +464,7 @@ ssize_t nfs_file_direct_read(struct kiocb *iocb, struct iov_iter *iter, dreq->iocb = iocb; NFS_I(inode)->read_io += count; - result = nfs_direct_read_schedule_iovec(dreq, iter, pos, uio); + result = nfs_direct_read_schedule_iovec(dreq, iter, pos); mutex_unlock(&inode->i_mutex); @@ -677,109 +620,6 @@ static void nfs_direct_write_complete(struct nfs_direct_req *dreq, struct inode } #endif -/* - * NB: Return the value of the first error return code. Subsequent - * errors after the first one are ignored. - */ -/* - * For each wsize'd chunk of the user's buffer, dispatch an NFS WRITE - * operation. If nfs_writedata_alloc() or get_user_pages() fails, - * bail and stop sending more writes. Write length accounting is - * handled automatically by nfs_direct_write_result(). Otherwise, if - * no requests have been sent, just return an error. - */ -static ssize_t nfs_direct_write_schedule_segment(struct nfs_pageio_descriptor *desc, - const struct iovec *iov, - loff_t pos, bool uio) -{ - struct nfs_direct_req *dreq = desc->pg_dreq; - struct nfs_open_context *ctx = dreq->ctx; - struct inode *inode = ctx->dentry->d_inode; - unsigned long user_addr = (unsigned long)iov->iov_base; - size_t count = iov->iov_len; - size_t wsize = NFS_SERVER(inode)->wsize; - unsigned int pgbase; - int result; - ssize_t started = 0; - struct page **pagevec = NULL; - unsigned int npages; - - do { - size_t bytes; - int i; - - pgbase = user_addr & ~PAGE_MASK; - bytes = min(max_t(size_t, wsize, PAGE_SIZE), count); - - result = -ENOMEM; - npages = nfs_page_array_len(pgbase, bytes); - if (!pagevec) - pagevec = kmalloc(npages * sizeof(struct page *), GFP_KERNEL); - if (!pagevec) - break; - - if (uio) { - down_read(¤t->mm->mmap_sem); - result = get_user_pages(current, current->mm, user_addr, - npages, 0, 0, pagevec, NULL); - up_read(¤t->mm->mmap_sem); - if (result < 0) - break; - } else { - WARN_ON(npages != 1); - result = get_kernel_page(user_addr, 0, pagevec); - if (WARN_ON(result != 1)) - break; - } - - if ((unsigned)result < npages) { - bytes = result * PAGE_SIZE; - if (bytes <= pgbase) { - nfs_direct_release_pages(pagevec, result); - break; - } - bytes -= pgbase; - npages = result; - } - - for (i = 0; i < npages; i++) { - struct nfs_page *req; - unsigned int req_len = min_t(size_t, bytes, PAGE_SIZE - pgbase); - - req = nfs_create_request(dreq->ctx, dreq->inode, - pagevec[i], - pgbase, req_len); - if (IS_ERR(req)) { - result = PTR_ERR(req); - break; - } - nfs_lock_request(req); - req->wb_index = pos >> PAGE_SHIFT; - req->wb_offset = pos & ~PAGE_MASK; - if (!nfs_pageio_add_request(desc, req)) { - result = desc->pg_error; - nfs_unlock_and_release_request(req); - break; - } - pgbase = 0; - bytes -= req_len; - started += req_len; - user_addr += req_len; - pos += req_len; - count -= req_len; - dreq->bytes_left -= req_len; - } - /* The nfs_page now hold references to these pages */ - nfs_direct_release_pages(pagevec, npages); - } while (count != 0 && result >= 0); - - kfree(pagevec); - - if (started) - return started; - return result < 0 ? (ssize_t) result : -EFAULT; -} - static void nfs_direct_write_completion(struct nfs_pgio_header *hdr) { struct nfs_direct_req *dreq = hdr->dreq; @@ -859,15 +699,27 @@ static const struct nfs_pgio_completion_ops nfs_direct_write_completion_ops = { .completion = nfs_direct_write_completion, }; + +/* + * NB: Return the value of the first error return code. Subsequent + * errors after the first one are ignored. + */ +/* + * For each wsize'd chunk of the user's buffer, dispatch an NFS WRITE + * operation. If nfs_writedata_alloc() or get_user_pages() fails, + * bail and stop sending more writes. Write length accounting is + * handled automatically by nfs_direct_write_result(). Otherwise, if + * no requests have been sent, just return an error. + */ static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq, struct iov_iter *iter, - loff_t pos, bool uio) + loff_t pos) { struct nfs_pageio_descriptor desc; struct inode *inode = dreq->inode; ssize_t result = 0; size_t requested_bytes = 0; - unsigned long seg; + size_t wsize = max_t(size_t, NFS_SERVER(inode)->wsize, PAGE_SIZE); NFS_PROTO(inode)->write_pageio_init(&desc, inode, FLUSH_COND_STABLE, &nfs_direct_write_completion_ops); @@ -875,16 +727,50 @@ static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq, get_dreq(dreq); atomic_inc(&inode->i_dio_count); - NFS_I(dreq->inode)->write_io += iov_iter_count(iter); - for (seg = 0; seg < iter->nr_segs; seg++) { - const struct iovec *vec = &iter->iov[seg]; - result = nfs_direct_write_schedule_segment(&desc, vec, pos, uio); + NFS_I(inode)->write_io += iov_iter_count(iter); + while (iov_iter_count(iter)) { + struct page **pagevec; + size_t bytes; + size_t pgbase; + unsigned npages, i; + + result = iov_iter_get_pages_alloc(iter, &pagevec, + wsize, &pgbase); if (result < 0) break; - requested_bytes += result; - if ((size_t)result < vec->iov_len) + + bytes = result; + iov_iter_advance(iter, bytes); + npages = (result + pgbase + PAGE_SIZE - 1) / PAGE_SIZE; + for (i = 0; i < npages; i++) { + struct nfs_page *req; + unsigned int req_len = min_t(size_t, bytes, PAGE_SIZE - pgbase); + + req = nfs_create_request(dreq->ctx, inode, + pagevec[i], + pgbase, req_len); + if (IS_ERR(req)) { + result = PTR_ERR(req); + break; + } + nfs_lock_request(req); + req->wb_index = pos >> PAGE_SHIFT; + req->wb_offset = pos & ~PAGE_MASK; + if (!nfs_pageio_add_request(&desc, req)) { + result = desc.pg_error; + nfs_unlock_and_release_request(req); + break; + } + pgbase = 0; + bytes -= req_len; + requested_bytes += req_len; + pos += req_len; + dreq->bytes_left -= req_len; + } + nfs_direct_release_pages(pagevec, npages); + kvfree(pagevec); + if (result < 0) break; - pos += vec->iov_len; } nfs_pageio_complete(&desc); @@ -985,7 +871,7 @@ ssize_t nfs_file_direct_write(struct kiocb *iocb, struct iov_iter *iter, if (!is_sync_kiocb(iocb)) dreq->iocb = iocb; - result = nfs_direct_write_schedule_iovec(dreq, iter, pos, uio); + result = nfs_direct_write_schedule_iovec(dreq, iter, pos); if (mapping->nrpages) { invalidate_inode_pages2_range(mapping, diff --git a/include/linux/uio.h b/include/linux/uio.h index 2f8825b..4876e9f 100644 --- a/include/linux/uio.h +++ b/include/linux/uio.h @@ -73,6 +73,8 @@ void iov_iter_init(struct iov_iter *i, int direction, const struct iovec *iov, unsigned long nr_segs, size_t count); ssize_t iov_iter_get_pages(struct iov_iter *i, struct page **pages, size_t maxsize, size_t *start); +ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, struct page ***pages, + size_t maxsize, size_t *start); int iov_iter_npages(const struct iov_iter *i, int maxpages); static inline size_t iov_iter_count(struct iov_iter *i) diff --git a/mm/iov_iter.c b/mm/iov_iter.c index 0b677f8..a5c691c 100644 --- a/mm/iov_iter.c +++ b/mm/iov_iter.c @@ -1,6 +1,8 @@ #include #include #include +#include +#include size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes, struct iov_iter *i) @@ -263,6 +265,44 @@ ssize_t iov_iter_get_pages(struct iov_iter *i, } EXPORT_SYMBOL(iov_iter_get_pages); +ssize_t iov_iter_get_pages_alloc(struct iov_iter *i, + struct page ***pages, size_t maxsize, + size_t *start) +{ + size_t offset = i->iov_offset; + const struct iovec *iov = i->iov; + size_t len; + unsigned long addr; + void *p; + int n; + int res; + + len = iov->iov_len - offset; + if (len > i->count) + len = i->count; + if (len > maxsize) + len = maxsize; + addr = (unsigned long)iov->iov_base + offset; + len += *start = addr & (PAGE_SIZE - 1); + addr &= ~(PAGE_SIZE - 1); + n = (len + PAGE_SIZE - 1) / PAGE_SIZE; + + p = kmalloc(n * sizeof(struct page *), GFP_KERNEL); + if (!p) + p = vmalloc(n * sizeof(struct page *)); + if (!p) + return -ENOMEM; + + res = get_user_pages_fast(addr, n, (i->type & WRITE) != WRITE, p); + if (unlikely(res < 0)) { + kvfree(p); + return res; + } + *pages = p; + return (res == n ? len : res * PAGE_SIZE) - *start; +} +EXPORT_SYMBOL(iov_iter_get_pages_alloc); + int iov_iter_npages(const struct iov_iter *i, int maxpages) { size_t offset = i->iov_offset;