Commit 507df40e authored by Chuck Lever's avatar Chuck Lever

NFSD: Hoist rq_vec preparation into nfsd_read()

Accrue the following benefits:

a) Deduplicate this common bit of code.

b) Don't prepare rq_vec for NFSv2 and NFSv3 spliced reads, which
   don't use rq_vec. This is already the case for
   nfsd4_encode_read().

c) Eventually, converting NFSD's read path to use a bvec iterator
   will be simpler.

In the next patch, nfsd_iter_read() will replace nfsd_readv() for
all NFS versions.
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
parent ed4a567a
...@@ -151,8 +151,6 @@ nfsd3_proc_read(struct svc_rqst *rqstp) ...@@ -151,8 +151,6 @@ nfsd3_proc_read(struct svc_rqst *rqstp)
{ {
struct nfsd3_readargs *argp = rqstp->rq_argp; struct nfsd3_readargs *argp = rqstp->rq_argp;
struct nfsd3_readres *resp = rqstp->rq_resp; struct nfsd3_readres *resp = rqstp->rq_resp;
unsigned int len;
int v;
dprintk("nfsd: READ(3) %s %lu bytes at %Lu\n", dprintk("nfsd: READ(3) %s %lu bytes at %Lu\n",
SVCFH_fmt(&argp->fh), SVCFH_fmt(&argp->fh),
...@@ -166,17 +164,7 @@ nfsd3_proc_read(struct svc_rqst *rqstp) ...@@ -166,17 +164,7 @@ nfsd3_proc_read(struct svc_rqst *rqstp)
if (argp->offset + argp->count > (u64)OFFSET_MAX) if (argp->offset + argp->count > (u64)OFFSET_MAX)
argp->count = (u64)OFFSET_MAX - argp->offset; argp->count = (u64)OFFSET_MAX - argp->offset;
v = 0;
len = argp->count;
resp->pages = rqstp->rq_next_page; resp->pages = rqstp->rq_next_page;
while (len > 0) {
struct page *page = *(rqstp->rq_next_page++);
rqstp->rq_vec[v].iov_base = page_address(page);
rqstp->rq_vec[v].iov_len = min_t(unsigned int, len, PAGE_SIZE);
len -= rqstp->rq_vec[v].iov_len;
v++;
}
/* Obtain buffer pointer for payload. /* Obtain buffer pointer for payload.
* 1 (status) + 22 (post_op_attr) + 1 (count) + 1 (eof) * 1 (status) + 22 (post_op_attr) + 1 (count) + 1 (eof)
...@@ -187,7 +175,7 @@ nfsd3_proc_read(struct svc_rqst *rqstp) ...@@ -187,7 +175,7 @@ nfsd3_proc_read(struct svc_rqst *rqstp)
fh_copy(&resp->fh, &argp->fh); fh_copy(&resp->fh, &argp->fh);
resp->status = nfsd_read(rqstp, &resp->fh, argp->offset, resp->status = nfsd_read(rqstp, &resp->fh, argp->offset,
rqstp->rq_vec, v, &resp->count, &resp->eof); &resp->count, &resp->eof);
return rpc_success; return rpc_success;
} }
......
...@@ -176,9 +176,7 @@ nfsd_proc_read(struct svc_rqst *rqstp) ...@@ -176,9 +176,7 @@ nfsd_proc_read(struct svc_rqst *rqstp)
{ {
struct nfsd_readargs *argp = rqstp->rq_argp; struct nfsd_readargs *argp = rqstp->rq_argp;
struct nfsd_readres *resp = rqstp->rq_resp; struct nfsd_readres *resp = rqstp->rq_resp;
unsigned int len;
u32 eof; u32 eof;
int v;
dprintk("nfsd: READ %s %d bytes at %d\n", dprintk("nfsd: READ %s %d bytes at %d\n",
SVCFH_fmt(&argp->fh), SVCFH_fmt(&argp->fh),
...@@ -187,17 +185,7 @@ nfsd_proc_read(struct svc_rqst *rqstp) ...@@ -187,17 +185,7 @@ nfsd_proc_read(struct svc_rqst *rqstp)
argp->count = min_t(u32, argp->count, NFSSVC_MAXBLKSIZE_V2); argp->count = min_t(u32, argp->count, NFSSVC_MAXBLKSIZE_V2);
argp->count = min_t(u32, argp->count, rqstp->rq_res.buflen); argp->count = min_t(u32, argp->count, rqstp->rq_res.buflen);
v = 0;
len = argp->count;
resp->pages = rqstp->rq_next_page; resp->pages = rqstp->rq_next_page;
while (len > 0) {
struct page *page = *(rqstp->rq_next_page++);
rqstp->rq_vec[v].iov_base = page_address(page);
rqstp->rq_vec[v].iov_len = min_t(unsigned int, len, PAGE_SIZE);
len -= rqstp->rq_vec[v].iov_len;
v++;
}
/* Obtain buffer pointer for payload. 19 is 1 word for /* Obtain buffer pointer for payload. 19 is 1 word for
* status, 17 words for fattr, and 1 word for the byte count. * status, 17 words for fattr, and 1 word for the byte count.
...@@ -207,7 +195,7 @@ nfsd_proc_read(struct svc_rqst *rqstp) ...@@ -207,7 +195,7 @@ nfsd_proc_read(struct svc_rqst *rqstp)
resp->count = argp->count; resp->count = argp->count;
fh_copy(&resp->fh, &argp->fh); fh_copy(&resp->fh, &argp->fh);
resp->status = nfsd_read(rqstp, &resp->fh, argp->offset, resp->status = nfsd_read(rqstp, &resp->fh, argp->offset,
rqstp->rq_vec, v, &resp->count, &eof); &resp->count, &eof);
if (resp->status == nfs_ok) if (resp->status == nfs_ok)
resp->status = fh_getattr(&resp->fh, &resp->stat); resp->status = fh_getattr(&resp->fh, &resp->stat);
else if (resp->status == nfserr_jukebox) else if (resp->status == nfserr_jukebox)
......
...@@ -1036,6 +1036,50 @@ __be32 nfsd_readv(struct svc_rqst *rqstp, struct svc_fh *fhp, ...@@ -1036,6 +1036,50 @@ __be32 nfsd_readv(struct svc_rqst *rqstp, struct svc_fh *fhp,
return nfsd_finish_read(rqstp, fhp, file, offset, count, eof, host_err); return nfsd_finish_read(rqstp, fhp, file, offset, count, eof, host_err);
} }
/**
* nfsd_iter_read - Perform a VFS read using an iterator
* @rqstp: RPC transaction context
* @fhp: file handle of file to be read
* @file: opened struct file of file to be read
* @offset: starting byte offset
* @count: IN: requested number of bytes; OUT: number of bytes read
* @base: offset in first page of read buffer
* @eof: OUT: set non-zero if operation reached the end of the file
*
* Some filesystems or situations cannot use nfsd_splice_read. This
* function is the slightly less-performant fallback for those cases.
*
* Returns nfs_ok on success, otherwise an nfserr stat value is
* returned.
*/
__be32 nfsd_iter_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
struct file *file, loff_t offset, unsigned long *count,
unsigned int base, u32 *eof)
{
unsigned long v, total;
struct iov_iter iter;
loff_t ppos = offset;
struct page *page;
ssize_t host_err;
v = 0;
total = *count;
while (total) {
page = *(rqstp->rq_next_page++);
rqstp->rq_vec[v].iov_base = page_address(page) + base;
rqstp->rq_vec[v].iov_len = min_t(size_t, total, PAGE_SIZE - base);
total -= rqstp->rq_vec[v].iov_len;
++v;
base = 0;
}
WARN_ON_ONCE(v > ARRAY_SIZE(rqstp->rq_vec));
trace_nfsd_read_vector(rqstp, fhp, offset, *count);
iov_iter_kvec(&iter, ITER_DEST, rqstp->rq_vec, v, *count);
host_err = vfs_iter_read(file, &iter, &ppos, 0);
return nfsd_finish_read(rqstp, fhp, file, offset, count, eof, host_err);
}
/* /*
* Gathered writes: If another process is currently writing to the file, * Gathered writes: If another process is currently writing to the file,
* there's a high chance this is another nfsd (triggered by a bulk write * there's a high chance this is another nfsd (triggered by a bulk write
...@@ -1161,14 +1205,24 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf, ...@@ -1161,14 +1205,24 @@ nfsd_vfs_write(struct svc_rqst *rqstp, struct svc_fh *fhp, struct nfsd_file *nf,
return nfserr; return nfserr;
} }
/* /**
* Read data from a file. count must contain the requested read count * nfsd_read - Read data from a file
* on entry. On return, *count contains the number of bytes actually read. * @rqstp: RPC transaction context
* @fhp: file handle of file to be read
* @offset: starting byte offset
* @count: IN: requested number of bytes; OUT: number of bytes read
* @eof: OUT: set non-zero if operation reached the end of the file
*
* The caller must verify that there is enough space in @rqstp.rq_res
* to perform this operation.
*
* N.B. After this call fhp needs an fh_put * N.B. After this call fhp needs an fh_put
*
* Returns nfs_ok on success, otherwise an nfserr stat value is
* returned.
*/ */
__be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp, __be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
loff_t offset, struct kvec *vec, int vlen, unsigned long *count, loff_t offset, unsigned long *count, u32 *eof)
u32 *eof)
{ {
struct nfsd_file *nf; struct nfsd_file *nf;
struct file *file; struct file *file;
...@@ -1183,12 +1237,10 @@ __be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp, ...@@ -1183,12 +1237,10 @@ __be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
if (file->f_op->splice_read && test_bit(RQ_SPLICE_OK, &rqstp->rq_flags)) if (file->f_op->splice_read && test_bit(RQ_SPLICE_OK, &rqstp->rq_flags))
err = nfsd_splice_read(rqstp, fhp, file, offset, count, eof); err = nfsd_splice_read(rqstp, fhp, file, offset, count, eof);
else else
err = nfsd_readv(rqstp, fhp, file, offset, vec, vlen, count, eof); err = nfsd_iter_read(rqstp, fhp, file, offset, count, 0, eof);
nfsd_file_put(nf); nfsd_file_put(nf);
trace_nfsd_read_done(rqstp, fhp, offset, *count); trace_nfsd_read_done(rqstp, fhp, offset, *count);
return err; return err;
} }
......
...@@ -115,8 +115,12 @@ __be32 nfsd_readv(struct svc_rqst *rqstp, struct svc_fh *fhp, ...@@ -115,8 +115,12 @@ __be32 nfsd_readv(struct svc_rqst *rqstp, struct svc_fh *fhp,
struct kvec *vec, int vlen, struct kvec *vec, int vlen,
unsigned long *count, unsigned long *count,
u32 *eof); u32 *eof);
__be32 nfsd_read(struct svc_rqst *, struct svc_fh *, __be32 nfsd_iter_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
loff_t, struct kvec *, int, unsigned long *, struct file *file, loff_t offset,
unsigned long *count, unsigned int base,
u32 *eof);
__be32 nfsd_read(struct svc_rqst *rqstp, struct svc_fh *fhp,
loff_t offset, unsigned long *count,
u32 *eof); u32 *eof);
__be32 nfsd_write(struct svc_rqst *, struct svc_fh *, loff_t, __be32 nfsd_write(struct svc_rqst *, struct svc_fh *, loff_t,
struct kvec *, int, unsigned long *, struct kvec *, int, unsigned long *,
......
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