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Commit 91f79c43 authored by Al Viro's avatar Al Viro
Browse files

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: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent f67da30c

drivers/staging/lustre/lustre/llite/rw26.c

+37 −55
Original line number Diff line number Diff line
@@ -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;
@@ -407,37 +403,26 @@ 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 = 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,

							     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;

						     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
@@ -458,12 +443,9 @@ static ssize_t ll_direct_IO_26(int rw, struct kiocb *iocb, 


			GOTO(out, result);

		}



		iov_iter_advance(iter, result);

		tot_bytes += result;

		file_offset += result;

			iov_left -= result;

			user_addr += result;

		}

	}

out:

	LASSERT(obj->cob_transient_pages == 0);

fs/nfs/direct.c

+88 −202
Original line number Diff line number Diff line
@@ -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)



static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,

					      struct iov_iter *iter,

					      loff_t pos)

{

	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;

	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);



		pgbase = user_addr & ~PAGE_MASK;

		bytes = min(max_t(size_t, rsize, PAGE_SIZE), count);

	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);



		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(&current->mm->mmap_sem);

			result = get_user_pages(current, current->mm, user_addr,

					npages, 1, 0, pagevec, NULL);

			up_read(&current->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;

		}

	while (iov_iter_count(iter)) {

		struct page **pagevec;

		size_t bytes;

		size_t pgbase;

		unsigned npages, i;



		if ((unsigned)result < npages) {

			bytes = result * PAGE_SIZE;

			if (bytes <= pgbase) {

				nfs_direct_release_pages(pagevec, result);

		result = iov_iter_get_pages_alloc(iter, &pagevec, 

						  rsize, &pgbase);

		if (result < 0)

			break;

			}

			bytes -= pgbase;

			npages = result;

		}

	

		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(&current->mm->mmap_sem);

			result = get_user_pages(current, current->mm, user_addr,

						npages, 0, 0, pagevec, NULL);

			up_read(&current->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,

include/linux/uio.h

+2 −0
Original line number Diff line number Diff line
@@ -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)

mm/iov_iter.c

+40 −0
Original line number Diff line number Diff line 
#include <linux/export.h>

#include <linux/uio.h>

#include <linux/pagemap.h>

#include <linux/slab.h>

#include <linux/vmalloc.h>



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;