NFS: create common nfs_pgio_header for both read and write
In order to avoid duplicating all the data in nfs_read_data whenever we
split it up into multiple RPC calls (either due to a short read result
or due to rsize < PAGE_SIZE), we split out the bits that are the same
per RPC call into a separate "header" structure.
The goal this patch moves towards is to have a single header
refcounted by several rpc_data structures. Thus, want to always refer
from rpc_data to the header, and not the other way. This patch comes
close to that ideal, but the directio code currently needs some
special casing, isolated in the nfs_direct_[read_write]hdr_release()
functions. This will be dealt with in a future patch.
Signed-off-by: Fred Isaman <iisaman@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c
index fb7fbaa..56176af 100644
--- a/fs/nfs/direct.c
+++ b/fs/nfs/direct.c
@@ -242,7 +242,7 @@
{
struct nfs_read_data *data = calldata;
- struct nfs_direct_req *dreq = (struct nfs_direct_req *) data->req;
+ struct nfs_direct_req *dreq = (struct nfs_direct_req *)data->header->req;
int status = data->task.tk_status;
spin_lock(&dreq->lock);
@@ -269,6 +269,15 @@
.rpc_release = nfs_direct_read_release,
};
+static void nfs_direct_readhdr_release(struct nfs_read_header *rhdr)
+{
+ struct nfs_read_data *data = &rhdr->rpc_data;
+
+ if (data->pagevec != data->page_array)
+ kfree(data->pagevec);
+ nfs_readhdr_free(&rhdr->header);
+}
+
/*
* For each rsize'd chunk of the user's buffer, dispatch an NFS READ
* operation. If nfs_readdata_alloc() or get_user_pages() fails,
@@ -301,6 +310,7 @@
ssize_t started = 0;
do {
+ struct nfs_read_header *rhdr;
struct nfs_read_data *data;
size_t bytes;
@@ -308,23 +318,24 @@
bytes = min(rsize,count);
result = -ENOMEM;
- data = nfs_readdata_alloc(nfs_page_array_len(pgbase, bytes));
- if (unlikely(!data))
+ rhdr = nfs_readhdr_alloc(nfs_page_array_len(pgbase, bytes));
+ if (unlikely(!rhdr))
break;
+ data = &rhdr->rpc_data;
down_read(¤t->mm->mmap_sem);
result = get_user_pages(current, current->mm, user_addr,
data->npages, 1, 0, data->pagevec, NULL);
up_read(¤t->mm->mmap_sem);
if (result < 0) {
- nfs_readdata_free(data);
+ nfs_direct_readhdr_release(rhdr);
break;
}
if ((unsigned)result < data->npages) {
bytes = result * PAGE_SIZE;
if (bytes <= pgbase) {
nfs_direct_release_pages(data->pagevec, result);
- nfs_readdata_free(data);
+ nfs_direct_readhdr_release(rhdr);
break;
}
bytes -= pgbase;
@@ -333,9 +344,9 @@
get_dreq(dreq);
- data->req = (struct nfs_page *) dreq;
- data->inode = inode;
- data->cred = msg.rpc_cred;
+ rhdr->header.req = (struct nfs_page *) dreq;
+ rhdr->header.inode = inode;
+ rhdr->header.cred = msg.rpc_cred;
data->args.fh = NFS_FH(inode);
data->args.context = get_nfs_open_context(ctx);
data->args.lock_context = dreq->l_ctx;
@@ -447,13 +458,23 @@
return result;
}
+static void nfs_direct_writehdr_release(struct nfs_write_header *whdr)
+{
+ struct nfs_write_data *data = &whdr->rpc_data;
+
+ if (data->pagevec != data->page_array)
+ kfree(data->pagevec);
+ nfs_writehdr_free(&whdr->header);
+}
+
static void nfs_direct_free_writedata(struct nfs_direct_req *dreq)
{
while (!list_empty(&dreq->rewrite_list)) {
- struct nfs_write_data *data = list_entry(dreq->rewrite_list.next, struct nfs_write_data, pages);
- list_del(&data->pages);
- nfs_direct_release_pages(data->pagevec, data->npages);
- nfs_writedata_free(data);
+ struct nfs_pgio_header *hdr = list_entry(dreq->rewrite_list.next, struct nfs_pgio_header, pages);
+ struct nfs_write_header *whdr = container_of(hdr, struct nfs_write_header, header);
+ list_del(&hdr->pages);
+ nfs_direct_release_pages(whdr->rpc_data.pagevec, whdr->rpc_data.npages);
+ nfs_direct_writehdr_release(whdr);
}
}
@@ -463,6 +484,7 @@
struct inode *inode = dreq->inode;
struct list_head *p;
struct nfs_write_data *data;
+ struct nfs_pgio_header *hdr;
struct rpc_task *task;
struct rpc_message msg = {
.rpc_cred = dreq->ctx->cred,
@@ -479,7 +501,8 @@
get_dreq(dreq);
list_for_each(p, &dreq->rewrite_list) {
- data = list_entry(p, struct nfs_write_data, pages);
+ hdr = list_entry(p, struct nfs_pgio_header, pages);
+ data = &(container_of(hdr, struct nfs_write_header, header))->rpc_data;
get_dreq(dreq);
@@ -652,7 +675,8 @@
static void nfs_direct_write_release(void *calldata)
{
struct nfs_write_data *data = calldata;
- struct nfs_direct_req *dreq = (struct nfs_direct_req *) data->req;
+ struct nfs_pgio_header *hdr = data->header;
+ struct nfs_direct_req *dreq = (struct nfs_direct_req *) hdr->req;
int status = data->task.tk_status;
spin_lock(&dreq->lock);
@@ -684,7 +708,7 @@
spin_unlock(&dreq->lock);
if (put_dreq(dreq))
- nfs_direct_write_complete(dreq, data->inode);
+ nfs_direct_write_complete(dreq, hdr->inode);
}
static const struct rpc_call_ops nfs_write_direct_ops = {
@@ -725,6 +749,7 @@
ssize_t started = 0;
do {
+ struct nfs_write_header *whdr;
struct nfs_write_data *data;
size_t bytes;
@@ -732,23 +757,25 @@
bytes = min(wsize,count);
result = -ENOMEM;
- data = nfs_writedata_alloc(nfs_page_array_len(pgbase, bytes));
- if (unlikely(!data))
+ whdr = nfs_writehdr_alloc(nfs_page_array_len(pgbase, bytes));
+ if (unlikely(!whdr))
break;
+ data = &whdr->rpc_data;
+
down_read(¤t->mm->mmap_sem);
result = get_user_pages(current, current->mm, user_addr,
data->npages, 0, 0, data->pagevec, NULL);
up_read(¤t->mm->mmap_sem);
if (result < 0) {
- nfs_writedata_free(data);
+ nfs_direct_writehdr_release(whdr);
break;
}
if ((unsigned)result < data->npages) {
bytes = result * PAGE_SIZE;
if (bytes <= pgbase) {
nfs_direct_release_pages(data->pagevec, result);
- nfs_writedata_free(data);
+ nfs_direct_writehdr_release(whdr);
break;
}
bytes -= pgbase;
@@ -757,11 +784,11 @@
get_dreq(dreq);
- list_move_tail(&data->pages, &dreq->rewrite_list);
+ list_move_tail(&whdr->header.pages, &dreq->rewrite_list);
- data->req = (struct nfs_page *) dreq;
- data->inode = inode;
- data->cred = msg.rpc_cred;
+ whdr->header.req = (struct nfs_page *) dreq;
+ whdr->header.inode = inode;
+ whdr->header.cred = msg.rpc_cred;
data->args.fh = NFS_FH(inode);
data->args.context = ctx;
data->args.lock_context = dreq->l_ctx;