This patch adds support to process write calls passed by io_submit()
asynchronously. It based on the previously introduced async context
that allows to process i/o responses in a separate thread and
return the caller immediately for asynchronous calls.
This improves writing performance of single threaded applications
with increasing of i/o queue depth size.
Signed-off-by: Pavel Shilovsky <pshilov@xxxxxxxxxxxxx>
---
fs/cifs/cifsglob.h | 2 +
fs/cifs/file.c | 188 ++++++++++++++++++++++++++++++++++++++---------------
2 files changed, 139 insertions(+), 51 deletions(-)
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 9438c7c..5c0e11a 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -1124,6 +1124,7 @@ struct cifs_aio_ctx {
struct kiocb *iocb;
struct cifsFileInfo *cfile;
struct bio_vec *bv;
+ loff_t pos;
unsigned int npages;
ssize_t rc;
unsigned int len;
@@ -1171,6 +1172,7 @@ struct cifs_writedata {
enum writeback_sync_modes sync_mode;
struct work_struct work;
struct cifsFileInfo *cfile;
+ struct cifs_aio_ctx *ctx;
__u64 offset;
pid_t pid;
unsigned int bytes;
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 9564e2c..6ef78ad 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -2458,11 +2458,14 @@ cifs_uncached_writedata_release(struct kref *refcount)
struct cifs_writedata *wdata = container_of(refcount,
struct cifs_writedata, refcount);
+ kref_put(&wdata->ctx->refcount, cifs_aio_ctx_release);
for (i = 0; i < wdata->nr_pages; i++)
put_page(wdata->pages[i]);
cifs_writedata_release(refcount);
}
+static void collect_uncached_write_data(struct cifs_aio_ctx *ctx);
+
static void
cifs_uncached_writev_complete(struct work_struct *work)
{
@@ -2478,7 +2481,8 @@ cifs_uncached_writev_complete(struct work_struct *work)
spin_unlock(&inode->i_lock);
complete(&wdata->done);
-
+ collect_uncached_write_data(wdata->ctx);
+ /* the below call can possibly free the last ref to aio ctx */
kref_put(&wdata->refcount, cifs_uncached_writedata_release);
}
@@ -2527,7 +2531,8 @@ wdata_fill_from_iovec(struct cifs_writedata *wdata, struct iov_iter *from,
static int
cifs_write_from_iter(loff_t offset, size_t len, struct iov_iter *from,
struct cifsFileInfo *open_file,
- struct cifs_sb_info *cifs_sb, struct list_head *wdata_list)
+ struct cifs_sb_info *cifs_sb, struct list_head *wdata_list,
+ struct cifs_aio_ctx *ctx)
{
int rc = 0;
size_t cur_len;
@@ -2595,6 +2600,8 @@ cifs_write_from_iter(loff_t offset, size_t len, struct iov_iter *from,
wdata->pagesz = PAGE_SIZE;
wdata->tailsz = cur_len - ((nr_pages - 1) * PAGE_SIZE);
wdata->credits = credits;
+ wdata->ctx = ctx;
+ kref_get(&ctx->refcount);
if (!wdata->cfile->invalidHandle ||
!(rc = cifs_reopen_file(wdata->cfile, false)))
@@ -2620,81 +2627,61 @@ cifs_write_from_iter(loff_t offset, size_t len, struct iov_iter *from,
return rc;
}
-ssize_t cifs_user_writev(struct kiocb *iocb, struct iov_iter *from)
+static void collect_uncached_write_data(struct cifs_aio_ctx *ctx)
{
- struct file *file = iocb->ki_filp;
- ssize_t total_written = 0;
- struct cifsFileInfo *open_file;
+ struct cifs_writedata *wdata, *tmp;
struct cifs_tcon *tcon;
struct cifs_sb_info *cifs_sb;
- struct cifs_writedata *wdata, *tmp;
- struct list_head wdata_list;
- struct iov_iter saved_from = *from;
+ struct dentry *dentry = ctx->cfile->dentry;
+ unsigned int i;
int rc;
- /*
- * BB - optimize the way when signing is disabled. We can drop this
- * extra memory-to-memory copying and use iovec buffers for constructing
- * write request.
- */
-
- rc = generic_write_checks(iocb, from);
- if (rc <= 0)
- return rc;
-
- INIT_LIST_HEAD(&wdata_list);
- cifs_sb = CIFS_FILE_SB(file);
- open_file = file->private_data;
- tcon = tlink_tcon(open_file->tlink);
-
- if (!tcon->ses->server->ops->async_writev)
- return -ENOSYS;
+ tcon = tlink_tcon(ctx->cfile->tlink);
+ cifs_sb = CIFS_SB(dentry->d_sb);
- rc = cifs_write_from_iter(iocb->ki_pos, iov_iter_count(from), from,
- open_file, cifs_sb, &wdata_list);
+ mutex_lock(&ctx->aio_mutex);
- /*
- * If at least one write was successfully sent, then discard any rc
- * value from the later writes. If the other write succeeds, then
- * we'll end up returning whatever was written. If it fails, then
- * we'll get a new rc value from that.
- */
- if (!list_empty(&wdata_list))
- rc = 0;
+ if (list_empty(&ctx->list)) {
+ mutex_unlock(&ctx->aio_mutex);
+ return;
+ }
+ rc = ctx->rc;
/*
* Wait for and collect replies for any successful sends in order of
- * increasing offset. Once an error is hit or we get a fatal signal
- * while waiting, then return without waiting for any more replies.
+ * increasing offset. Once an error is hit, then return without waiting
+ * for any more replies.
*/
restart_loop:
- list_for_each_entry_safe(wdata, tmp, &wdata_list, list) {
+ list_for_each_entry_safe(wdata, tmp, &ctx->list, list) {
if (!rc) {
- /* FIXME: freezable too? */
- rc = wait_for_completion_killable(&wdata->done);
- if (rc)
- rc = -EINTR;
- else if (wdata->result)
+ if (!try_wait_for_completion(&wdata->done)) {
+ mutex_unlock(&ctx->aio_mutex);
+ return;
+ }
+
+ if (wdata->result)
rc = wdata->result;
else
- total_written += wdata->bytes;
+ ctx->total_len += wdata->bytes;
/* resend call if it's a retryable error */
if (rc == -EAGAIN) {
struct list_head tmp_list;
- struct iov_iter tmp_from = saved_from;
+ struct iov_iter tmp_from = ctx->iter;
INIT_LIST_HEAD(&tmp_list);
list_del_init(&wdata->list);
iov_iter_advance(&tmp_from,
- wdata->offset - iocb->ki_pos);
+ wdata->offset - ctx->pos);
rc = cifs_write_from_iter(wdata->offset,
wdata->bytes, &tmp_from,
- open_file, cifs_sb, &tmp_list);
+ ctx->cfile, cifs_sb, &tmp_list,
+ ctx);
- list_splice(&tmp_list, &wdata_list);
+ list_splice(&tmp_list, &ctx->list);
kref_put(&wdata->refcount,
cifs_uncached_writedata_release);
@@ -2705,12 +2692,111 @@ ssize_t cifs_user_writev(struct kiocb *iocb, struct iov_iter *from)
kref_put(&wdata->refcount, cifs_uncached_writedata_release);
}
+ for (i = 0; i < ctx->npages; i++)
+ put_page(ctx->bv[i].bv_page);
+
+ cifs_stats_bytes_written(tcon, ctx->total_len);
+ set_bit(CIFS_INO_INVALID_MAPPING, &CIFS_I(dentry->d_inode)->flags);
+
+ ctx->rc = (rc == 0) ? ctx->total_len : rc;
+
+ mutex_unlock(&ctx->aio_mutex);
+
+ if (ctx->iocb && ctx->iocb->ki_complete)
+ ctx->iocb->ki_complete(ctx->iocb, ctx->rc, 0);
+ else
+ complete(&ctx->done);
+}
+
+ssize_t cifs_user_writev(struct kiocb *iocb, struct iov_iter *from)
+{
+ struct file *file = iocb->ki_filp;
+ ssize_t total_written = 0;
+ struct cifsFileInfo *cfile;
+ struct cifs_tcon *tcon;
+ struct cifs_sb_info *cifs_sb;
+ struct cifs_aio_ctx *ctx;
+ struct iov_iter saved_from = *from;
+ int rc;
+
+ /*
+ * BB - optimize the way when signing is disabled. We can drop this
+ * extra memory-to-memory copying and use iovec buffers for constructing
+ * write request.
+ */
+
+ rc = generic_write_checks(iocb, from);
+ if (rc <= 0)
+ return rc;
+
+ cifs_sb = CIFS_FILE_SB(file);
+ cfile = file->private_data;
+ tcon = tlink_tcon(cfile->tlink);
+
+ if (!tcon->ses->server->ops->async_writev)
+ return -ENOSYS;
+
+ ctx = cifs_aio_ctx_alloc();
+ if (!ctx)
+ return -ENOMEM;
+
+ ctx->cfile = cifsFileInfo_get(cfile);
+
+ if (!is_sync_kiocb(iocb))
+ ctx->iocb = iocb;
+
+ ctx->pos = iocb->ki_pos;
+
+ rc = setup_aio_ctx_iter(ctx, from, WRITE);
+ if (rc) {
+ kref_put(&ctx->refcount, cifs_aio_ctx_release);
+ return rc;
+ }
+
+ /* grab a lock here due to read response handlers can access ctx */
+ mutex_lock(&ctx->aio_mutex);
+
+ rc = cifs_write_from_iter(iocb->ki_pos, ctx->len, &saved_from,
+ cfile, cifs_sb, &ctx->list, ctx);
+
+ /*
+ * If at least one write was successfully sent, then discard any rc
+ * value from the later writes. If the other write succeeds, then
+ * we'll end up returning whatever was written. If it fails, then
+ * we'll get a new rc value from that.
+ */
+ if (!list_empty(&ctx->list))
+ rc = 0;
+
+ mutex_unlock(&ctx->aio_mutex);
+
+ if (rc) {
+ kref_put(&ctx->refcount, cifs_aio_ctx_release);
+ return rc;
+ }
+
+ if (!is_sync_kiocb(iocb)) {
+ kref_put(&ctx->refcount, cifs_aio_ctx_release);
+ return -EIOCBQUEUED;
+ }
+
+ rc = wait_for_completion_killable(&ctx->done);
+ if (rc) {
+ mutex_lock(&ctx->aio_mutex);
+ ctx->rc = rc = -EINTR;
+ total_written = ctx->total_len;
+ mutex_unlock(&ctx->aio_mutex);
+ } else {
+ rc = ctx->rc;
+ total_written = ctx->total_len;
+ }
+
+ kref_put(&ctx->refcount, cifs_aio_ctx_release);
+
if (unlikely(!total_written))
return rc;
iocb->ki_pos += total_written;
- set_bit(CIFS_INO_INVALID_MAPPING, &CIFS_I(file_inode(file))->flags);
- cifs_stats_bytes_written(tcon, total_written);
return total_written;
}
--
2.7.4
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