[PATCH v2 3/4] btrfs/ioctl: store btrfs_uring_encoded_data in io_btrfs_cmd

[Caleb Sander Mateos <csander@purestorage.com>]

btrfs is the only user of struct io_uring_cmd_data and its op_data
field. Switch its ->uring_cmd() implementations to store the struct
btrfs_uring_encoded_data * in the struct io_btrfs_cmd, overlayed with
io_uring_cmd's pdu field. This avoids having to touch another cache line
to access the struct btrfs_uring_encoded_data *, and allows op_data and
struct io_uring_cmd_data to be removed.

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
---
 fs/btrfs/ioctl.c | 38 +++++++++++++++++++++++++++-----------
 1 file changed, 27 insertions(+), 11 deletions(-)

diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index ff15160e2581..6183729c93a1 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -4627,10 +4627,17 @@ static int btrfs_ioctl_encoded_write(struct file *file, void __user *argp, bool
 		add_wchar(current, ret);
 	inc_syscw(current);
 	return ret;
 }
 
+struct btrfs_uring_encoded_data {
+	struct btrfs_ioctl_encoded_io_args args;
+	struct iovec iovstack[UIO_FASTIOV];
+	struct iovec *iov;
+	struct iov_iter iter;
+};
+
 /*
  * Context that's attached to an encoded read io_uring command, in cmd->pdu. It
  * contains the fields in btrfs_uring_read_extent that are necessary to finish
  * off and cleanup the I/O in btrfs_uring_read_finished.
  */
@@ -4648,10 +4655,11 @@ struct btrfs_uring_priv {
 	int err;
 	bool compressed;
 };
 
 struct io_btrfs_cmd {
+	struct btrfs_uring_encoded_data *data;
 	struct btrfs_uring_priv *priv;
 };
 
 static void btrfs_uring_read_finished(struct io_uring_cmd *cmd, unsigned int issue_flags)
 {
@@ -4706,10 +4714,11 @@ static void btrfs_uring_read_finished(struct io_uring_cmd *cmd, unsigned int iss
 		__free_page(priv->pages[index]);
 
 	kfree(priv->pages);
 	kfree(priv->iov);
 	kfree(priv);
+	kfree(bc->data);
 }
 
 void btrfs_uring_read_extent_endio(void *ctx, int err)
 {
 	struct btrfs_uring_priv *priv = ctx;
@@ -4789,17 +4798,10 @@ static int btrfs_uring_read_extent(struct kiocb *iocb, struct iov_iter *iter,
 	btrfs_inode_unlock(inode, BTRFS_ILOCK_SHARED);
 	kfree(priv);
 	return ret;
 }
 
-struct btrfs_uring_encoded_data {
-	struct btrfs_ioctl_encoded_io_args args;
-	struct iovec iovstack[UIO_FASTIOV];
-	struct iovec *iov;
-	struct iov_iter iter;
-};
-
 static int btrfs_uring_encoded_read(struct io_uring_cmd *cmd, unsigned int issue_flags)
 {
 	size_t copy_end_kernel = offsetofend(struct btrfs_ioctl_encoded_io_args, flags);
 	size_t copy_end;
 	int ret;
@@ -4811,11 +4813,15 @@ static int btrfs_uring_encoded_read(struct io_uring_cmd *cmd, unsigned int issue
 	loff_t pos;
 	struct kiocb kiocb;
 	struct extent_state *cached_state = NULL;
 	u64 start, lockend;
 	void __user *sqe_addr;
-	struct btrfs_uring_encoded_data *data = io_uring_cmd_get_async_data(cmd)->op_data;
+	struct io_btrfs_cmd *bc = io_uring_cmd_to_pdu(cmd, struct io_btrfs_cmd);
+	struct btrfs_uring_encoded_data *data = NULL;
+
+	if (cmd->flags & IORING_URING_CMD_REISSUE)
+		data = bc->data;
 
 	if (!capable(CAP_SYS_ADMIN)) {
 		ret = -EPERM;
 		goto out_acct;
 	}
@@ -4841,11 +4847,11 @@ static int btrfs_uring_encoded_read(struct io_uring_cmd *cmd, unsigned int issue
 		if (!data) {
 			ret = -ENOMEM;
 			goto out_acct;
 		}
 
-		io_uring_cmd_get_async_data(cmd)->op_data = data;
+		bc->data = data;
 
 		if (issue_flags & IO_URING_F_COMPAT) {
 #if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT)
 			struct btrfs_ioctl_encoded_io_args_32 args32;
 
@@ -4939,21 +4945,28 @@ static int btrfs_uring_encoded_read(struct io_uring_cmd *cmd, unsigned int issue
 out_acct:
 	if (ret > 0)
 		add_rchar(current, ret);
 	inc_syscr(current);
 
+	if (ret != -EIOCBQUEUED && ret != -EAGAIN)
+		kfree(data);
+
 	return ret;
 }
 
 static int btrfs_uring_encoded_write(struct io_uring_cmd *cmd, unsigned int issue_flags)
 {
 	loff_t pos;
 	struct kiocb kiocb;
 	struct file *file;
 	ssize_t ret;
 	void __user *sqe_addr;
-	struct btrfs_uring_encoded_data *data = io_uring_cmd_get_async_data(cmd)->op_data;
+	struct io_btrfs_cmd *bc = io_uring_cmd_to_pdu(cmd, struct io_btrfs_cmd);
+	struct btrfs_uring_encoded_data *data = NULL;
+
+	if (cmd->flags & IORING_URING_CMD_REISSUE)
+		data = bc->data;
 
 	if (!capable(CAP_SYS_ADMIN)) {
 		ret = -EPERM;
 		goto out_acct;
 	}
@@ -4971,11 +4984,11 @@ static int btrfs_uring_encoded_write(struct io_uring_cmd *cmd, unsigned int issu
 		if (!data) {
 			ret = -ENOMEM;
 			goto out_acct;
 		}
 
-		io_uring_cmd_get_async_data(cmd)->op_data = data;
+		bc->data = data;
 
 		if (issue_flags & IO_URING_F_COMPAT) {
 #if defined(CONFIG_64BIT) && defined(CONFIG_COMPAT)
 			struct btrfs_ioctl_encoded_io_args_32 args32;
 
@@ -5061,10 +5074,13 @@ static int btrfs_uring_encoded_write(struct io_uring_cmd *cmd, unsigned int issu
 	kfree(data->iov);
 out_acct:
 	if (ret > 0)
 		add_wchar(current, ret);
 	inc_syscw(current);
+
+	if (ret != -EAGAIN)
+		kfree(data);
 	return ret;
 }
 
 int btrfs_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags)
 {
-- 
2.45.2