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Message-ID: <20120919163308.29482.77401.stgit@maximpc.sw.ru>
Date: Wed, 19 Sep 2012 20:33:12 +0400
From: Maxim Patlasov <mpatlasov@...allels.com>
To: miklos@...redi.hu
Cc: fuse-devel@...ts.sourceforge.net, linux-kernel@...r.kernel.org,
devel@...nvz.org
Subject: [PATCH 09/11] 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@...allels.com>
---
fs/fuse/file.c | 108 +++++++++++++++++++++++++++++---------------------------
1 files changed, 55 insertions(+), 53 deletions(-)
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 8a1f833..db9efb5 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -1056,11 +1056,15 @@ static inline void fuse_page_descs_length_init(struct fuse_req *req)
req->page_descs[i].offset;
}
-static int fuse_get_user_pages(struct fuse_req *req, const char __user *buf,
+static int fuse_get_user_pages(struct fuse_req *req,
+ const struct iovec **iov_pp,
+ unsigned long *nr_segs_p,
+ size_t *iov_offset_p,
size_t *nbytesp, int write)
{
size_t nbytes = *nbytesp;
- unsigned long user_addr = (unsigned long) buf;
+ size_t frag_size = min_t(size_t, nbytes, (*iov_pp)->iov_len - *iov_offset_p);
+ unsigned long user_addr = (unsigned long)(*iov_pp)->iov_base + *iov_offset_p;
unsigned offset = user_addr & ~PAGE_MASK;
int npages;
@@ -1071,10 +1075,13 @@ static int fuse_get_user_pages(struct fuse_req *req, const char __user *buf,
else
req->out.args[0].value = (void *) user_addr;
+ (*iov_pp)++;
+ (*nr_segs_p)--;
+ *nbytesp = frag_size;
return 0;
}
- nbytes = min_t(size_t, nbytes, FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT);
+ nbytes = min_t(size_t, frag_size, FUSE_MAX_PAGES_PER_REQ << PAGE_SHIFT);
npages = (nbytes + offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
npages = clamp(npages, 1, FUSE_MAX_PAGES_PER_REQ);
npages = get_user_pages_fast(user_addr, npages, !write, req->pages);
@@ -1092,17 +1099,26 @@ static int fuse_get_user_pages(struct fuse_req *req, const char __user *buf,
nbytes = (req->num_pages << PAGE_SHIFT) - req->page_descs[0].offset;
- if (*nbytesp < nbytes)
+ if (frag_size < nbytes)
req->page_descs[req->num_pages - 1].length -=
- nbytes - *nbytesp;
+ nbytes - frag_size;
- *nbytesp = min(*nbytesp, nbytes);
+ *nbytesp = min(frag_size, nbytes);
+
+ if (*nbytesp < (*iov_pp)->iov_len - *iov_offset_p) {
+ *iov_offset_p += *nbytesp;
+ } else {
+ (*iov_pp)++;
+ (*nr_segs_p)--;
+ *iov_offset_p = 0;
+ }
return 0;
}
-ssize_t fuse_direct_io(struct file *file, const char __user *buf,
- size_t count, loff_t *ppos, int write)
+static ssize_t __fuse_direct_io(struct file *file, const struct iovec *iov,
+ unsigned long nr_segs, size_t count,
+ loff_t *ppos, int write)
{
struct fuse_file *ff = file->private_data;
struct fuse_conn *fc = ff->fc;
@@ -1110,6 +1126,7 @@ ssize_t fuse_direct_io(struct file *file, const char __user *buf,
loff_t pos = *ppos;
ssize_t res = 0;
struct fuse_req *req;
+ size_t iov_offset = 0;
req = fuse_get_req(fc, FUSE_MAX_PAGES_PER_REQ);
if (IS_ERR(req))
@@ -1119,7 +1136,8 @@ ssize_t fuse_direct_io(struct file *file, const char __user *buf,
size_t nres;
fl_owner_t owner = current->files;
size_t nbytes = min(count, nmax);
- int err = fuse_get_user_pages(req, buf, &nbytes, write);
+ int err = fuse_get_user_pages(req, &iov, &nr_segs, &iov_offset,
+ &nbytes, write);
if (err) {
res = err;
break;
@@ -1142,7 +1160,6 @@ ssize_t fuse_direct_io(struct file *file, const char __user *buf,
count -= nres;
res += nres;
pos += nres;
- buf += nres;
if (nres != nbytes)
break;
if (count) {
@@ -1159,10 +1176,17 @@ ssize_t fuse_direct_io(struct file *file, const char __user *buf,
return res;
}
+
+ssize_t fuse_direct_io(struct file *file, const char __user *buf,
+ size_t count, loff_t *ppos, int write)
+{
+ struct iovec iov = { .iov_base = (void *)buf, .iov_len = count };
+ return __fuse_direct_io(file, &iov, 1, count, ppos, write);
+}
EXPORT_SYMBOL_GPL(fuse_direct_io);
-static ssize_t fuse_direct_read(struct file *file, char __user *buf,
- size_t count, loff_t *ppos)
+static ssize_t __fuse_direct_read(struct file *file, const struct iovec *iov,
+ unsigned long nr_segs, loff_t *ppos)
{
ssize_t res;
struct inode *inode = file->f_path.dentry->d_inode;
@@ -1170,22 +1194,31 @@ static ssize_t fuse_direct_read(struct file *file, char __user *buf,
if (is_bad_inode(inode))
return -EIO;
- res = fuse_direct_io(file, buf, count, ppos, 0);
+ res = __fuse_direct_io(file, iov, nr_segs, iov_length(iov, nr_segs),
+ ppos, 0);
fuse_invalidate_attr(inode);
return res;
}
-static ssize_t __fuse_direct_write(struct file *file, const char __user *buf,
- size_t count, loff_t *ppos)
+static ssize_t fuse_direct_read(struct file *file, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct iovec iov = { .iov_base = (void *)buf, .iov_len = count };
+ return __fuse_direct_read(file, &iov, 1, ppos);
+}
+
+static ssize_t __fuse_direct_write(struct file *file, const struct iovec *iov,
+ unsigned long nr_segs, loff_t *ppos)
{
struct inode *inode = file->f_path.dentry->d_inode;
+ size_t count = iov_length(iov, nr_segs);
ssize_t res;
res = generic_write_checks(file, ppos, &count, 0);
if (!res) {
- res = fuse_direct_io(file, buf, count, ppos, 1);
+ res = __fuse_direct_io(file, iov, nr_segs, count, ppos, 1);
if (res > 0)
fuse_write_update_size(inode, *ppos);
}
@@ -1198,6 +1231,7 @@ static ssize_t __fuse_direct_write(struct file *file, const char __user *buf,
static ssize_t fuse_direct_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
+ struct iovec iov = { .iov_base = (void *)buf, .iov_len = count };
struct inode *inode = file->f_path.dentry->d_inode;
ssize_t res;
@@ -1206,7 +1240,7 @@ static ssize_t fuse_direct_write(struct file *file, const char __user *buf,
/* Don't allow parallel writes to the same file */
mutex_lock(&inode->i_mutex);
- res = __fuse_direct_write(file, buf, count, ppos);
+ res = __fuse_direct_write(file, &iov, 1, ppos);
mutex_unlock(&inode->i_mutex);
return res;
@@ -2166,41 +2200,6 @@ int fuse_notify_poll_wakeup(struct fuse_conn *fc,
return 0;
}
-static ssize_t fuse_loop_dio(struct file *filp, const struct iovec *iov,
- unsigned long nr_segs, loff_t *ppos, int rw)
-{
- const struct iovec *vector = iov;
- ssize_t ret = 0;
-
- while (nr_segs > 0) {
- void __user *base;
- size_t len;
- ssize_t nr;
-
- base = vector->iov_base;
- len = vector->iov_len;
- vector++;
- nr_segs--;
-
- if (rw == WRITE)
- nr = __fuse_direct_write(filp, base, len, ppos);
- else
- nr = fuse_direct_read(filp, base, len, ppos);
-
- if (nr < 0) {
- if (!ret)
- ret = nr;
- break;
- }
- ret += nr;
- if (nr != len)
- break;
- }
-
- return ret;
-}
-
-
static ssize_t
fuse_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
loff_t offset, unsigned long nr_segs)
@@ -2212,7 +2211,10 @@ fuse_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
file = iocb->ki_filp;
pos = offset;
- ret = fuse_loop_dio(file, iov, nr_segs, &pos, rw);
+ if (rw == WRITE)
+ ret = __fuse_direct_write(file, iov, nr_segs, &pos);
+ else
+ ret = __fuse_direct_read(file, iov, nr_segs, &pos);
return ret;
}
--
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