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fuse: pass iov[] to fuse_get_user_pages()
The patch makes preliminary work for the next patch optimizing scatter-gather direct IO. The idea is to allow fuse_get_user_pages() to pack as many iov-s to each fuse request as possible. So, here we only rework all related call-paths to carry iov[] from fuse_direct_IO() to fuse_get_user_pages(). Signed-off-by: Maxim Patlasov <mpatlasov@parallels.com> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
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parent
d28574e043
commit
b98d023a24
1 changed files with 49 additions and 54 deletions
103
fs/fuse/file.c
103
fs/fuse/file.c
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@ -1056,14 +1056,18 @@ static inline void fuse_page_descs_length_init(struct fuse_req *req)
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req->page_descs[i].offset;
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}
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static int fuse_get_user_pages(struct fuse_req *req, const char __user *buf,
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static int fuse_get_user_pages(struct fuse_req *req, struct iov_iter *ii,
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size_t *nbytesp, int write)
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{
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size_t nbytes = *nbytesp;
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unsigned long user_addr = (unsigned long) buf;
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unsigned offset = user_addr & ~PAGE_MASK;
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size_t frag_size = min(iov_iter_single_seg_count(ii), nbytes);
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unsigned long user_addr;
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unsigned offset;
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int npages;
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user_addr = (unsigned long)ii->iov->iov_base + ii->iov_offset;
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offset = user_addr & ~PAGE_MASK;
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/* Special case for kernel I/O: can copy directly into the buffer */
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if (segment_eq(get_fs(), KERNEL_DS)) {
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if (write)
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@ -1071,10 +1075,12 @@ static int fuse_get_user_pages(struct fuse_req *req, const char __user *buf,
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else
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req->out.args[0].value = (void *) user_addr;
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iov_iter_advance(ii, frag_size);
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*nbytesp = frag_size;
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return 0;
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}
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nbytes = min_t(size_t, nbytes, FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT);
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nbytes = min_t(size_t, frag_size, FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT);
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npages = (nbytes + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
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npages = clamp(npages, 1, FUSE_MAX_PAGES_PER_REQ);
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npages = get_user_pages_fast(user_addr, npages, !write, req->pages);
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@ -1092,17 +1098,19 @@ static int fuse_get_user_pages(struct fuse_req *req, const char __user *buf,
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nbytes = (req->num_pages << PAGE_SHIFT) - req->page_descs[0].offset;
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if (*nbytesp < nbytes)
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if (frag_size < nbytes)
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req->page_descs[req->num_pages - 1].length -=
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nbytes - *nbytesp;
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nbytes - frag_size;
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*nbytesp = min(*nbytesp, nbytes);
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*nbytesp = min(frag_size, nbytes);
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iov_iter_advance(ii, *nbytesp);
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return 0;
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}
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ssize_t fuse_direct_io(struct file *file, const char __user *buf,
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size_t count, loff_t *ppos, int write)
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static ssize_t __fuse_direct_io(struct file *file, const struct iovec *iov,
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unsigned long nr_segs, size_t count,
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loff_t *ppos, int write)
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{
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struct fuse_file *ff = file->private_data;
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struct fuse_conn *fc = ff->fc;
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@ -1110,6 +1118,9 @@ ssize_t fuse_direct_io(struct file *file, const char __user *buf,
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loff_t pos = *ppos;
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ssize_t res = 0;
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struct fuse_req *req;
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struct iov_iter ii;
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iov_iter_init(&ii, iov, nr_segs, count, 0);
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req = fuse_get_req(fc, FUSE_MAX_PAGES_PER_REQ);
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if (IS_ERR(req))
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@ -1119,7 +1130,7 @@ ssize_t fuse_direct_io(struct file *file, const char __user *buf,
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size_t nres;
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fl_owner_t owner = current->files;
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size_t nbytes = min(count, nmax);
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int err = fuse_get_user_pages(req, buf, &nbytes, write);
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int err = fuse_get_user_pages(req, &ii, &nbytes, write);
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if (err) {
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res = err;
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break;
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@ -1142,7 +1153,6 @@ ssize_t fuse_direct_io(struct file *file, const char __user *buf,
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count -= nres;
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res += nres;
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pos += nres;
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buf += nres;
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if (nres != nbytes)
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break;
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if (count) {
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@ -1159,10 +1169,17 @@ ssize_t fuse_direct_io(struct file *file, const char __user *buf,
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return res;
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}
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ssize_t fuse_direct_io(struct file *file, const char __user *buf,
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size_t count, loff_t *ppos, int write)
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{
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struct iovec iov = { .iov_base = (void *)buf, .iov_len = count };
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return __fuse_direct_io(file, &iov, 1, count, ppos, write);
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}
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EXPORT_SYMBOL_GPL(fuse_direct_io);
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static ssize_t fuse_direct_read(struct file *file, char __user *buf,
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size_t count, loff_t *ppos)
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static ssize_t __fuse_direct_read(struct file *file, const struct iovec *iov,
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unsigned long nr_segs, loff_t *ppos)
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{
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ssize_t res;
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struct inode *inode = file->f_path.dentry->d_inode;
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@ -1170,22 +1187,31 @@ static ssize_t fuse_direct_read(struct file *file, char __user *buf,
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if (is_bad_inode(inode))
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return -EIO;
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res = fuse_direct_io(file, buf, count, ppos, 0);
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res = __fuse_direct_io(file, iov, nr_segs, iov_length(iov, nr_segs),
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ppos, 0);
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fuse_invalidate_attr(inode);
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return res;
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}
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static ssize_t __fuse_direct_write(struct file *file, const char __user *buf,
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size_t count, loff_t *ppos)
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static ssize_t fuse_direct_read(struct file *file, char __user *buf,
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size_t count, loff_t *ppos)
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{
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struct iovec iov = { .iov_base = (void *)buf, .iov_len = count };
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return __fuse_direct_read(file, &iov, 1, ppos);
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}
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static ssize_t __fuse_direct_write(struct file *file, const struct iovec *iov,
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unsigned long nr_segs, loff_t *ppos)
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{
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struct inode *inode = file->f_path.dentry->d_inode;
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size_t count = iov_length(iov, nr_segs);
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ssize_t res;
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res = generic_write_checks(file, ppos, &count, 0);
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if (!res) {
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res = fuse_direct_io(file, buf, count, ppos, 1);
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res = __fuse_direct_io(file, iov, nr_segs, count, ppos, 1);
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if (res > 0)
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fuse_write_update_size(inode, *ppos);
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}
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@ -1198,6 +1224,7 @@ static ssize_t __fuse_direct_write(struct file *file, const char __user *buf,
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static ssize_t fuse_direct_write(struct file *file, const char __user *buf,
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size_t count, loff_t *ppos)
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{
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struct iovec iov = { .iov_base = (void *)buf, .iov_len = count };
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struct inode *inode = file->f_path.dentry->d_inode;
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ssize_t res;
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@ -1206,7 +1233,7 @@ static ssize_t fuse_direct_write(struct file *file, const char __user *buf,
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/* Don't allow parallel writes to the same file */
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mutex_lock(&inode->i_mutex);
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res = __fuse_direct_write(file, buf, count, ppos);
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res = __fuse_direct_write(file, &iov, 1, ppos);
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mutex_unlock(&inode->i_mutex);
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return res;
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@ -2167,41 +2194,6 @@ int fuse_notify_poll_wakeup(struct fuse_conn *fc,
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return 0;
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}
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static ssize_t fuse_loop_dio(struct file *filp, const struct iovec *iov,
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unsigned long nr_segs, loff_t *ppos, int rw)
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{
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const struct iovec *vector = iov;
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ssize_t ret = 0;
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while (nr_segs > 0) {
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void __user *base;
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size_t len;
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ssize_t nr;
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base = vector->iov_base;
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len = vector->iov_len;
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vector++;
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nr_segs--;
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if (rw == WRITE)
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nr = __fuse_direct_write(filp, base, len, ppos);
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else
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nr = fuse_direct_read(filp, base, len, ppos);
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if (nr < 0) {
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if (!ret)
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ret = nr;
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break;
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}
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ret += nr;
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if (nr != len)
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break;
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}
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return ret;
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}
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static ssize_t
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fuse_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
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loff_t offset, unsigned long nr_segs)
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@ -2213,7 +2205,10 @@ fuse_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
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file = iocb->ki_filp;
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pos = offset;
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ret = fuse_loop_dio(file, iov, nr_segs, &pos, rw);
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if (rw == WRITE)
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ret = __fuse_direct_write(file, iov, nr_segs, &pos);
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else
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ret = __fuse_direct_read(file, iov, nr_segs, &pos);
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return ret;
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}
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