diff mbox series

[for-6.13,05/19] nfs/localio: remove extra indirect nfs_to call to check {read,write}_iter

Message ID 20241108234002.16392-6-snitzer@kernel.org (mailing list archive)
State New
Headers show
Series nfs/nfsd: fixes and improvements for LOCALIO | expand

Commit Message

Mike Snitzer Nov. 8, 2024, 11:39 p.m. UTC 
Push the read_iter and write_iter availability checks down to
nfs_do_local_read and nfs_do_local_write respectively.

This eliminates a redundant nfs_to->nfsd_file_file() call.

Signed-off-by: Mike Snitzer <snitzer@kernel.org>
---
 fs/nfs/localio.c | 32 +++++++++++++++++++-------------
 1 file changed, 19 insertions(+), 13 deletions(-)

Comments

NeilBrown Nov. 11, 2024, 1:20 a.m. UTC | #1 
On Sat, 09 Nov 2024, Mike Snitzer wrote:
> Push the read_iter and write_iter availability checks down to
> nfs_do_local_read and nfs_do_local_write respectively.
> 
> This eliminates a redundant nfs_to->nfsd_file_file() call.

Do it?

The patch removes 2 of these calls and add 2 of these calls.  So it
isn't clear what is being eliminated.

Maybe it is a good think to do, but it isn't obvious to me why.

Thanks,
NeilBrown


> 
> Signed-off-by: Mike Snitzer <snitzer@kernel.org>
> ---
>  fs/nfs/localio.c | 32 +++++++++++++++++++-------------
>  1 file changed, 19 insertions(+), 13 deletions(-)
> 
> diff --git a/fs/nfs/localio.c b/fs/nfs/localio.c
> index a7eb83a604d0..a77ac7e8a05c 100644
> --- a/fs/nfs/localio.c
> +++ b/fs/nfs/localio.c
> @@ -273,7 +273,7 @@ nfs_local_iocb_free(struct nfs_local_kiocb *iocb)
>  
>  static struct nfs_local_kiocb *
>  nfs_local_iocb_alloc(struct nfs_pgio_header *hdr,
> -		     struct nfsd_file *localio, gfp_t flags)
> +		     struct file *file, gfp_t flags)
>  {
>  	struct nfs_local_kiocb *iocb;
>  
> @@ -286,9 +286,8 @@ nfs_local_iocb_alloc(struct nfs_pgio_header *hdr,
>  		kfree(iocb);
>  		return NULL;
>  	}
> -	init_sync_kiocb(&iocb->kiocb, nfs_to->nfsd_file_file(localio));
> +	init_sync_kiocb(&iocb->kiocb, file);
>  	iocb->kiocb.ki_pos = hdr->args.offset;
> -	iocb->localio = localio;
>  	iocb->hdr = hdr;
>  	iocb->kiocb.ki_flags &= ~IOCB_APPEND;
>  	return iocb;
> @@ -395,13 +394,19 @@ nfs_do_local_read(struct nfs_pgio_header *hdr,
>  		  const struct rpc_call_ops *call_ops)
>  {
>  	struct nfs_local_kiocb *iocb;
> +	struct file *file = nfs_to->nfsd_file_file(localio);
> +
> +	/* Don't support filesystems without read_iter */
> +	if (!file->f_op->read_iter)
> +		return -EAGAIN;
>  
>  	dprintk("%s: vfs_read count=%u pos=%llu\n",
>  		__func__, hdr->args.count, hdr->args.offset);
>  
> -	iocb = nfs_local_iocb_alloc(hdr, localio, GFP_KERNEL);
> +	iocb = nfs_local_iocb_alloc(hdr, file, GFP_KERNEL);
>  	if (iocb == NULL)
>  		return -ENOMEM;
> +	iocb->localio = localio;
>  
>  	nfs_local_pgio_init(hdr, call_ops);
>  	hdr->res.eof = false;
> @@ -564,14 +569,20 @@ nfs_do_local_write(struct nfs_pgio_header *hdr,
>  		   const struct rpc_call_ops *call_ops)
>  {
>  	struct nfs_local_kiocb *iocb;
> +	struct file *file = nfs_to->nfsd_file_file(localio);
> +
> +	/* Don't support filesystems without write_iter */
> +	if (!file->f_op->write_iter)
> +		return -EAGAIN;
>  
>  	dprintk("%s: vfs_write count=%u pos=%llu %s\n",
>  		__func__, hdr->args.count, hdr->args.offset,
>  		(hdr->args.stable == NFS_UNSTABLE) ?  "unstable" : "stable");
>  
> -	iocb = nfs_local_iocb_alloc(hdr, localio, GFP_NOIO);
> +	iocb = nfs_local_iocb_alloc(hdr, file, GFP_NOIO);
>  	if (iocb == NULL)
>  		return -ENOMEM;
> +	iocb->localio = localio;
>  
>  	switch (hdr->args.stable) {
>  	default:
> @@ -597,16 +608,9 @@ int nfs_local_doio(struct nfs_client *clp, struct nfsd_file *localio,
>  		   const struct rpc_call_ops *call_ops)
>  {
>  	int status = 0;
> -	struct file *filp = nfs_to->nfsd_file_file(localio);
>  
>  	if (!hdr->args.count)
>  		return 0;
> -	/* Don't support filesystems without read_iter/write_iter */
> -	if (!filp->f_op->read_iter || !filp->f_op->write_iter) {
> -		nfs_local_disable(clp);
> -		status = -EAGAIN;
> -		goto out;
> -	}
>  
>  	switch (hdr->rw_mode) {
>  	case FMODE_READ:
> @@ -620,8 +624,10 @@ int nfs_local_doio(struct nfs_client *clp, struct nfsd_file *localio,
>  			hdr->rw_mode);
>  		status = -EINVAL;
>  	}
> -out:
> +
>  	if (status != 0) {
> +		if (status == -EAGAIN)
> +			nfs_local_disable(clp);
>  		nfs_to_nfsd_file_put_local(localio);
>  		hdr->task.tk_status = status;
>  		nfs_local_hdr_release(hdr, call_ops);
> -- 
> 2.44.0
> 
>
Mike Snitzer Nov. 11, 2024, 3:09 p.m. UTC | #2 
On Mon, Nov 11, 2024 at 12:20:12PM +1100, NeilBrown wrote:
> On Sat, 09 Nov 2024, Mike Snitzer wrote:
> > Push the read_iter and write_iter availability checks down to
> > nfs_do_local_read and nfs_do_local_write respectively.
> > 
> > This eliminates a redundant nfs_to->nfsd_file_file() call.
> 
> Do it?

It does.. it is harder to see just from looking at the patch.

> The patch removes 2 of these calls and add 2 of these calls.  So it
> isn't clear what is being eliminated.
> 
> Maybe it is a good thing to do, but it isn't obvious to me why.

nfs_local_doio() is common to both read and write, and both
nfs_do_local_read() and nfs_do_local_write() already call
nfs_to->nfsd_file_file(). This patch simply pushes nfs_local_doio()'s
nfs_to->nfsd_file_file() call down to nfs_do_local_{read,write} (or
put differently: moves their respective calls earlier) to kill 2 birds
with 1 stone.  Hence it eliminates an extra call to
nfs_to->nfsd_file_file() in both read and write paths.

Mike
diff mbox series

Patch

diff --git a/fs/nfs/localio.c b/fs/nfs/localio.c
index a7eb83a604d0..a77ac7e8a05c 100644
--- a/fs/nfs/localio.c
+++ b/fs/nfs/localio.c
@@ -273,7 +273,7 @@  nfs_local_iocb_free(struct nfs_local_kiocb *iocb)
 
 static struct nfs_local_kiocb *
 nfs_local_iocb_alloc(struct nfs_pgio_header *hdr,
-		     struct nfsd_file *localio, gfp_t flags)
+		     struct file *file, gfp_t flags)
 {
 	struct nfs_local_kiocb *iocb;
 
@@ -286,9 +286,8 @@  nfs_local_iocb_alloc(struct nfs_pgio_header *hdr,
 		kfree(iocb);
 		return NULL;
 	}
-	init_sync_kiocb(&iocb->kiocb, nfs_to->nfsd_file_file(localio));
+	init_sync_kiocb(&iocb->kiocb, file);
 	iocb->kiocb.ki_pos = hdr->args.offset;
-	iocb->localio = localio;
 	iocb->hdr = hdr;
 	iocb->kiocb.ki_flags &= ~IOCB_APPEND;
 	return iocb;
@@ -395,13 +394,19 @@  nfs_do_local_read(struct nfs_pgio_header *hdr,
 		  const struct rpc_call_ops *call_ops)
 {
 	struct nfs_local_kiocb *iocb;
+	struct file *file = nfs_to->nfsd_file_file(localio);
+
+	/* Don't support filesystems without read_iter */
+	if (!file->f_op->read_iter)
+		return -EAGAIN;
 
 	dprintk("%s: vfs_read count=%u pos=%llu\n",
 		__func__, hdr->args.count, hdr->args.offset);
 
-	iocb = nfs_local_iocb_alloc(hdr, localio, GFP_KERNEL);
+	iocb = nfs_local_iocb_alloc(hdr, file, GFP_KERNEL);
 	if (iocb == NULL)
 		return -ENOMEM;
+	iocb->localio = localio;
 
 	nfs_local_pgio_init(hdr, call_ops);
 	hdr->res.eof = false;
@@ -564,14 +569,20 @@  nfs_do_local_write(struct nfs_pgio_header *hdr,
 		   const struct rpc_call_ops *call_ops)
 {
 	struct nfs_local_kiocb *iocb;
+	struct file *file = nfs_to->nfsd_file_file(localio);
+
+	/* Don't support filesystems without write_iter */
+	if (!file->f_op->write_iter)
+		return -EAGAIN;
 
 	dprintk("%s: vfs_write count=%u pos=%llu %s\n",
 		__func__, hdr->args.count, hdr->args.offset,
 		(hdr->args.stable == NFS_UNSTABLE) ?  "unstable" : "stable");
 
-	iocb = nfs_local_iocb_alloc(hdr, localio, GFP_NOIO);
+	iocb = nfs_local_iocb_alloc(hdr, file, GFP_NOIO);
 	if (iocb == NULL)
 		return -ENOMEM;
+	iocb->localio = localio;
 
 	switch (hdr->args.stable) {
 	default:
@@ -597,16 +608,9 @@  int nfs_local_doio(struct nfs_client *clp, struct nfsd_file *localio,
 		   const struct rpc_call_ops *call_ops)
 {
 	int status = 0;
-	struct file *filp = nfs_to->nfsd_file_file(localio);
 
 	if (!hdr->args.count)
 		return 0;
-	/* Don't support filesystems without read_iter/write_iter */
-	if (!filp->f_op->read_iter || !filp->f_op->write_iter) {
-		nfs_local_disable(clp);
-		status = -EAGAIN;
-		goto out;
-	}
 
 	switch (hdr->rw_mode) {
 	case FMODE_READ:
@@ -620,8 +624,10 @@  int nfs_local_doio(struct nfs_client *clp, struct nfsd_file *localio,
 			hdr->rw_mode);
 		status = -EINVAL;
 	}
-out:
+
 	if (status != 0) {
+		if (status == -EAGAIN)
+			nfs_local_disable(clp);
 		nfs_to_nfsd_file_put_local(localio);
 		hdr->task.tk_status = status;
 		nfs_local_hdr_release(hdr, call_ops);