Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-11-11 06:31:49 +00:00
Code Issues Packages Projects Releases Wiki Activity

NFSD: Replace the internals of the READ_BUF() macro

Browse Source 
Convert the READ_BUF macro in nfs4xdr.c from open code to instead
use the new xdr_stream-style decoders already in use by the encode
side (and by the in-kernel NFS client implementation). Once this
conversion is done, each individual NFSv4 argument decoder can be
independently cleaned up to replace these macros with C code.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
This commit is contained in:
Chuck Lever 2020-11-03 11:54:23 -05:00
parent 08281341be
commit c1346a1216
5 changed files with 77 additions and 165 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
fs/nfsd/nfs4proc.c
View File

@ -1023,8 +1023,8 @@ nfsd4_write(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
write->wr_how_written = write->wr_stable_how;
nvecs = svc_fill_write_vector(rqstp, write->wr_pagelist,
&write->wr_head, write->wr_buflen);
nvecs = svc_fill_write_vector(rqstp, write->wr_payload.pages,
write->wr_payload.head, write->wr_buflen);
WARN_ON_ONCE(nvecs > ARRAY_SIZE(rqstp->rq_vec));
status = nfsd_vfs_write(rqstp, &cstate->current_fh, nf,

181
fs/nfsd/nfs4xdr.c
View File

@ -131,90 +131,13 @@ xdr_error: \
memcpy((x), p, nbytes); \
p += XDR_QUADLEN(nbytes); \
} while (0)
/* READ_BUF, read_buf(): nbytes must be <= PAGE_SIZE */
#define READ_BUF(nbytes) do { \
if (nbytes <= (u32)((char *)argp->end - (char *)argp->p)) { \
p = argp->p; \
argp->p += XDR_QUADLEN(nbytes); \
} else if (!(p = read_buf(argp, nbytes))) { \
dprintk("NFSD: xdr error (%s:%d)\n", \
__FILE__, __LINE__); \
goto xdr_error; \
} \
} while (0)
static void next_decode_page(struct nfsd4_compoundargs *argp)
{
argp->p = page_address(argp->pagelist[0]);
argp->pagelist++;
if (argp->pagelen < PAGE_SIZE) {
argp->end = argp->p + XDR_QUADLEN(argp->pagelen);
argp->pagelen = 0;
} else {
argp->end = argp->p + (PAGE_SIZE>>2);
argp->pagelen -= PAGE_SIZE;
}
}
static __be32 *read_buf(struct nfsd4_compoundargs *argp, u32 nbytes)
{
/* We want more bytes than seem to be available.
* Maybe we need a new page, maybe we have just run out
*/
unsigned int avail = (char *)argp->end - (char *)argp->p;
__be32 *p;
if (argp->pagelen == 0) {
struct kvec *vec = &argp->rqstp->rq_arg.tail[0];
if (!argp->tail) {
argp->tail = true;
avail = vec->iov_len;
argp->p = vec->iov_base;
argp->end = vec->iov_base + avail;
}
if (avail < nbytes)
return NULL;
p = argp->p;
argp->p += XDR_QUADLEN(nbytes);
return p;
}
if (avail + argp->pagelen < nbytes)
return NULL;
if (avail + PAGE_SIZE < nbytes) /* need more than a page !! */
return NULL;
/* ok, we can do it with the current plus the next page */
if (nbytes <= sizeof(argp->tmp))
p = argp->tmp;
else {
kfree(argp->tmpp);
p = argp->tmpp = kmalloc(nbytes, GFP_KERNEL);
if (!p)
return NULL;
}
/*
* The following memcpy is safe because read_buf is always
* called with nbytes > avail, and the two cases above both
* guarantee p points to at least nbytes bytes.
*/
memcpy(p, argp->p, avail);
next_decode_page(argp);
memcpy(((char*)p)+avail, argp->p, (nbytes - avail));
argp->p += XDR_QUADLEN(nbytes - avail);
return p;
}
static unsigned int compoundargs_bytes_left(struct nfsd4_compoundargs *argp)
{
unsigned int this = (char *)argp->end - (char *)argp->p;
return this + argp->pagelen;
}
#define READ_BUF(nbytes) \
do { \
p = xdr_inline_decode(argp->xdr,\
nbytes); \
if (!p) \
goto xdr_error; \
} while (0)
static int zero_clientid(clientid_t *clid)
{
@ -261,44 +184,6 @@ svcxdr_dupstr(struct nfsd4_compoundargs *argp, void *buf, u32 len)
return p;
}
static __be32
svcxdr_construct_vector(struct nfsd4_compoundargs *argp, struct kvec *head,
struct page ***pagelist, u32 buflen)
{
int avail;
int len;
int pages;
/* Sorry .. no magic macros for this.. *
* READ_BUF(write->wr_buflen);
* SAVEMEM(write->wr_buf, write->wr_buflen);
*/
avail = (char *)argp->end - (char *)argp->p;
if (avail + argp->pagelen < buflen) {
dprintk("NFSD: xdr error (%s:%d)\n",
__FILE__, __LINE__);
return nfserr_bad_xdr;
}
head->iov_base = argp->p;
head->iov_len = avail;
*pagelist = argp->pagelist;
len = XDR_QUADLEN(buflen) << 2;
if (len >= avail) {
len -= avail;
pages = len >> PAGE_SHIFT;
argp->pagelist += pages;
argp->pagelen -= pages * PAGE_SIZE;
len -= pages * PAGE_SIZE;
next_decode_page(argp);
}
argp->p += XDR_QUADLEN(len);
return 0;
}
/**
* savemem - duplicate a chunk of memory for later processing
* @argp: NFSv4 compound argument structure to be freed with
@ -398,7 +283,7 @@ nfsd4_decode_fattr(struct nfsd4_compoundargs *argp, u32 *bmval,
READ_BUF(4); len += 4;
nace = be32_to_cpup(p++);
if (nace > compoundargs_bytes_left(argp)/20)
if (nace > xdr_stream_remaining(argp->xdr) / sizeof(struct nfs4_ace))
/*
* Even with 4-byte names there wouldn't be
* space for that many aces; something fishy is
@ -929,7 +814,7 @@ xdr_error:
static __be32 nfsd4_decode_opaque(struct nfsd4_compoundargs *argp, struct xdr_netobj *o)
{
__be32 *p;
DECODE_HEAD;
READ_BUF(4);
o->len = be32_to_cpup(p++);
@ -939,9 +824,8 @@ static __be32 nfsd4_decode_opaque(struct nfsd4_compoundargs *argp, struct xdr_ne
READ_BUF(o->len);
SAVEMEM(o->data, o->len);
return nfs_ok;
xdr_error:
return nfserr_bad_xdr;
DECODE_TAIL;
}
static __be32
@ -1319,10 +1203,8 @@ nfsd4_decode_write(struct nfsd4_compoundargs *argp, struct nfsd4_write *write)
goto xdr_error;
write->wr_buflen = be32_to_cpup(p++);
status = svcxdr_construct_vector(argp, &write->wr_head,
&write->wr_pagelist, write->wr_buflen);
if (status)
return status;
if (!xdr_stream_subsegment(argp->xdr, &write->wr_payload, write->wr_buflen))
goto xdr_error;
DECODE_TAIL;
}
@ -1891,13 +1773,14 @@ nfsd4_decode_seek(struct nfsd4_compoundargs *argp, struct nfsd4_seek *seek)
*/
/*
* Decode data into buffer. Uses head and pages constructed by
* svcxdr_construct_vector.
* Decode data into buffer.
*/
static __be32
nfsd4_vbuf_from_vector(struct nfsd4_compoundargs *argp, struct kvec *head,
struct page **pages, char **bufp, u32 buflen)
nfsd4_vbuf_from_vector(struct nfsd4_compoundargs *argp, struct xdr_buf *xdr,
char **bufp, u32 buflen)
{
struct page **pages = xdr->pages;
struct kvec *head = xdr->head;
char *tmp, *dp;
u32 len;
@ -2012,8 +1895,6 @@ nfsd4_decode_setxattr(struct nfsd4_compoundargs *argp,
{
DECODE_HEAD;
u32 flags, maxcount, size;
struct kvec head;
struct page **pagelist;
READ_BUF(4);
flags = be32_to_cpup(p++);
@ -2036,12 +1917,12 @@ nfsd4_decode_setxattr(struct nfsd4_compoundargs *argp,
setxattr->setxa_len = size;
if (size > 0) {
status = svcxdr_construct_vector(argp, &head, &pagelist, size);
if (status)
return status;
struct xdr_buf payload;
status = nfsd4_vbuf_from_vector(argp, &head, pagelist,
&setxattr->setxa_buf, size);
if (!xdr_stream_subsegment(argp->xdr, &payload, size))
goto xdr_error;
status = nfsd4_vbuf_from_vector(argp, &payload,
&setxattr->setxa_buf, size);
}
DECODE_TAIL;
@ -5288,8 +5169,6 @@ void nfsd4_release_compoundargs(struct svc_rqst *rqstp)
kfree(args->ops);
args->ops = args->iops;
}
kfree(args->tmpp);
args->tmpp = NULL;
while (args->to_free) {
struct svcxdr_tmpbuf *tb = args->to_free;
args->to_free = tb->next;
@ -5302,19 +5181,11 @@ nfs4svc_decode_compoundargs(struct svc_rqst *rqstp, __be32 *p)
{
struct nfsd4_compoundargs *args = rqstp->rq_argp;
if (rqstp->rq_arg.head[0].iov_len % 4) {
/* client is nuts */
dprintk("%s: compound not properly padded! (peeraddr=%pISc xid=0x%x)",
__func__, svc_addr(rqstp), be32_to_cpu(rqstp->rq_xid));
return 0;
}
args->p = p;
args->end = rqstp->rq_arg.head[0].iov_base + rqstp->rq_arg.head[0].iov_len;
args->pagelist = rqstp->rq_arg.pages;
args->pagelen = rqstp->rq_arg.page_len;
args->tail = false;
/* svcxdr_tmp_alloc */
args->tmpp = NULL;
args->to_free = NULL;
args->xdr = &rqstp->rq_arg_stream;
args->ops = args->iops;
args->rqstp = rqstp;

10
fs/nfsd/xdr4.h
View File

@ -419,8 +419,7 @@ struct nfsd4_write {
u64 wr_offset; /* request */
u32 wr_stable_how; /* request */
u32 wr_buflen; /* request */
struct kvec wr_head;
struct page ** wr_pagelist; /* request */
struct xdr_buf wr_payload; /* request */
u32 wr_bytes_written; /* response */
u32 wr_how_written; /* response */
@ -696,15 +695,10 @@ struct svcxdr_tmpbuf {
struct nfsd4_compoundargs {
/* scratch variables for XDR decode */
__be32 * p;
__be32 * end;
struct page ** pagelist;
int pagelen;
bool tail;
__be32 tmp[8];
__be32 * tmpp;
struct xdr_stream *xdr;
struct svcxdr_tmpbuf *to_free;
struct svc_rqst *rqstp;
u32 taglen;

2
include/linux/sunrpc/xdr.h
View File

@ -254,6 +254,8 @@ extern void xdr_enter_page(struct xdr_stream *xdr, unsigned int len);
extern int xdr_process_buf(struct xdr_buf *buf, unsigned int offset, unsigned int len, int (*actor)(struct scatterlist *, void *), void *data);
extern uint64_t xdr_align_data(struct xdr_stream *, uint64_t, uint32_t);
extern uint64_t xdr_expand_hole(struct xdr_stream *, uint64_t, uint64_t);
extern bool xdr_stream_subsegment(struct xdr_stream *xdr, struct xdr_buf *subbuf,
unsigned int len);
/**
* xdr_set_scratch_buffer - Attach a scratch buffer for decoding data.

45
net/sunrpc/xdr.c
View File

@ -1407,6 +1407,51 @@ int xdr_buf_subsegment(const struct xdr_buf *buf, struct xdr_buf *subbuf,
}
EXPORT_SYMBOL_GPL(xdr_buf_subsegment);
/**
* xdr_stream_subsegment - set @subbuf to a portion of @xdr
* @xdr: an xdr_stream set up for decoding
* @subbuf: the result buffer
* @nbytes: length of @xdr to extract, in bytes
*
* Sets up @subbuf to represent a portion of @xdr. The portion
* starts at the current offset in @xdr, and extends for a length
* of @nbytes. If this is successful, @xdr is advanced to the next
* position following that portion.
*
* Return values:
* %true: @subbuf has been initialized, and @xdr has been advanced.
* %false: a bounds error has occurred
*/
bool xdr_stream_subsegment(struct xdr_stream *xdr, struct xdr_buf *subbuf,
unsigned int nbytes)
{
unsigned int remaining, offset, len;
if (xdr_buf_subsegment(xdr->buf, subbuf, xdr_stream_pos(xdr), nbytes))
return false;
if (subbuf->head[0].iov_len)
if (!__xdr_inline_decode(xdr, subbuf->head[0].iov_len))
return false;
remaining = subbuf->page_len;
offset = subbuf->page_base;
while (remaining) {
len = min_t(unsigned int, remaining, PAGE_SIZE) - offset;
if (xdr->p == xdr->end && !xdr_set_next_buffer(xdr))
return false;
if (!__xdr_inline_decode(xdr, len))
return false;
remaining -= len;
offset = 0;
}
return true;
}
EXPORT_SYMBOL_GPL(xdr_stream_subsegment);
/**
* xdr_buf_trim - lop at most "len" bytes off the end of "buf"
* @buf: buf to be trimmed