Commit 3cc03b16 authored by NeilBrown's avatar NeilBrown Committed by Linus Torvalds
Browse files

[PATCH] knfsd: Avoid excess stack usage in svc_tcp_recvfrom 



..  by allocating the array of 'kvec' in 'struct svc_rqst'.

As we plan to increase RPCSVC_MAXPAGES from 8 upto 256, we can no longer
allocate an array of this size on the stack.  So we allocate it in 'struct
svc_rqst'.

However svc_rqst contains (indirectly) an array of the same type and size
(actually several, but they are in a union).  So rather than waste space, we
move those arrays out of the separately allocated union and into svc_rqst to
share with the kvec moved out of svc_tcp_recvfrom (various arrays are used at
different times, so there is no conflict).

Signed-off-by: default avatarNeil Brown <neilb@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 44524359

fs/nfsd/nfs3proc.c

+2 −2
Original line number Diff line number Diff line
@@ -180,7 +180,7 @@ nfsd3_proc_read(struct svc_rqst *rqstp, struct nfsd3_readargs *argp, 
	fh_copy(&resp->fh, &argp->fh);

	nfserr = nfsd_read(rqstp, &resp->fh, NULL,

				  argp->offset,

			   	  argp->vec, argp->vlen,

			   	  rqstp->rq_vec, argp->vlen,

				  &resp->count);

	if (nfserr == 0) {

		struct inode	*inode = resp->fh.fh_dentry->d_inode;
@@ -210,7 +210,7 @@ nfsd3_proc_write(struct svc_rqst *rqstp, struct nfsd3_writeargs *argp, 
	resp->committed = argp->stable;

	nfserr = nfsd_write(rqstp, &resp->fh, NULL,

				   argp->offset,

				   argp->vec, argp->vlen,

				   rqstp->rq_vec, argp->vlen,

				   argp->len,

				   &resp->committed);

	resp->count = argp->count;

fs/nfsd/nfs3xdr.c

+11 −11
Original line number Diff line number Diff line
@@ -344,9 +344,9 @@ nfs3svc_decode_readargs(struct svc_rqst *rqstp, u32 *p, 
	v=0;

	while (len > 0) {

		pn = rqstp->rq_resused++;

		args->vec[v].iov_base = page_address(rqstp->rq_respages[pn]);

		args->vec[v].iov_len = len < PAGE_SIZE? len : PAGE_SIZE;

		len -= args->vec[v].iov_len;

		rqstp->rq_vec[v].iov_base = page_address(rqstp->rq_respages[pn]);

		rqstp->rq_vec[v].iov_len = len < PAGE_SIZE? len : PAGE_SIZE;

		len -= rqstp->rq_vec[v].iov_len;

		v++;

	}

	args->vlen = v;
@@ -372,22 +372,22 @@ nfs3svc_decode_writeargs(struct svc_rqst *rqstp, u32 *p, 
	    rqstp->rq_arg.len - hdr < len)

		return 0;



	args->vec[0].iov_base = (void*)p;

	args->vec[0].iov_len = rqstp->rq_arg.head[0].iov_len - hdr;

	rqstp->rq_vec[0].iov_base = (void*)p;

	rqstp->rq_vec[0].iov_len = rqstp->rq_arg.head[0].iov_len - hdr;



	if (len > NFSSVC_MAXBLKSIZE)

		len = NFSSVC_MAXBLKSIZE;

	v=  0;

	while (len > args->vec[v].iov_len) {

		len -= args->vec[v].iov_len;

	while (len > rqstp->rq_vec[v].iov_len) {

		len -= rqstp->rq_vec[v].iov_len;

		v++;

		args->vec[v].iov_base = page_address(rqstp->rq_pages[v]);

		args->vec[v].iov_len = PAGE_SIZE;

		rqstp->rq_vec[v].iov_base = page_address(rqstp->rq_pages[v]);

		rqstp->rq_vec[v].iov_len = PAGE_SIZE;

	}

	args->vec[v].iov_len = len;

	rqstp->rq_vec[v].iov_len = len;

	args->vlen = v+1;



	return args->count == args->len && args->vec[0].iov_len > 0;

	return args->count == args->len && rqstp->rq_vec[0].iov_len > 0;

}



int

fs/nfsd/nfs4proc.c

+1 −1
Original line number Diff line number Diff line
@@ -646,7 +646,7 @@ nfsd4_write(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_writ 
	*p++ = nfssvc_boot.tv_usec;



	status =  nfsd_write(rqstp, current_fh, filp, write->wr_offset,

			write->wr_vec, write->wr_vlen, write->wr_buflen,

			rqstp->rq_vec, write->wr_vlen, write->wr_buflen,

			&write->wr_how_written);

	if (filp)

		fput(filp);

fs/nfsd/nfs4xdr.c

+13 −13
Original line number Diff line number Diff line
@@ -926,26 +926,26 @@ nfsd4_decode_write(struct nfsd4_compoundargs *argp, struct nfsd4_write *write) 
		printk(KERN_NOTICE "xdr error! (%s:%d)\n", __FILE__, __LINE__); 

		goto xdr_error;

	}

	write->wr_vec[0].iov_base = p;

	write->wr_vec[0].iov_len = avail;

	argp->rqstp->rq_vec[0].iov_base = p;

	argp->rqstp->rq_vec[0].iov_len = avail;

	v = 0;

	len = write->wr_buflen;

	while (len > write->wr_vec[v].iov_len) {

		len -= write->wr_vec[v].iov_len;

	while (len > argp->rqstp->rq_vec[v].iov_len) {

		len -= argp->rqstp->rq_vec[v].iov_len;

		v++;

		write->wr_vec[v].iov_base = page_address(argp->pagelist[0]);

		argp->rqstp->rq_vec[v].iov_base = page_address(argp->pagelist[0]);

		argp->pagelist++;

		if (argp->pagelen >= PAGE_SIZE) {

			write->wr_vec[v].iov_len = PAGE_SIZE;

			argp->rqstp->rq_vec[v].iov_len = PAGE_SIZE;

			argp->pagelen -= PAGE_SIZE;

		} else {

			write->wr_vec[v].iov_len = argp->pagelen;

			argp->rqstp->rq_vec[v].iov_len = argp->pagelen;

			argp->pagelen -= len;

		}

	}

	argp->end = (u32*) (write->wr_vec[v].iov_base + write->wr_vec[v].iov_len);

	argp->p = (u32*)  (write->wr_vec[v].iov_base + (XDR_QUADLEN(len) << 2));

	write->wr_vec[v].iov_len = len;

	argp->end = (u32*) (argp->rqstp->rq_vec[v].iov_base + argp->rqstp->rq_vec[v].iov_len);

	argp->p = (u32*)  (argp->rqstp->rq_vec[v].iov_base + (XDR_QUADLEN(len) << 2));

	argp->rqstp->rq_vec[v].iov_len = len;

	write->wr_vlen = v+1;



	DECODE_TAIL;
@@ -2063,9 +2063,9 @@ nfsd4_encode_read(struct nfsd4_compoundres *resp, int nfserr, 
	v = 0;

	while (len > 0) {

		pn = resp->rqstp->rq_resused++;

		read->rd_iov[v].iov_base =

		resp->rqstp->rq_vec[v].iov_base =

			page_address(resp->rqstp->rq_respages[pn]);

		read->rd_iov[v].iov_len =

		resp->rqstp->rq_vec[v].iov_len =

			len < PAGE_SIZE ? len : PAGE_SIZE;

		v++;

		len -= PAGE_SIZE;
@@ -2073,7 +2073,7 @@ nfsd4_encode_read(struct nfsd4_compoundres *resp, int nfserr, 
	read->rd_vlen = v;



	nfserr = nfsd_read(read->rd_rqstp, read->rd_fhp, read->rd_filp,

			read->rd_offset, read->rd_iov, read->rd_vlen,

			read->rd_offset, resp->rqstp->rq_vec, read->rd_vlen,

			&maxcount);



	if (nfserr == nfserr_symlink)

fs/nfsd/nfsproc.c

+2 −2
Original line number Diff line number Diff line
@@ -159,7 +159,7 @@ nfsd_proc_read(struct svc_rqst *rqstp, struct nfsd_readargs *argp, 
	resp->count = argp->count;

	nfserr = nfsd_read(rqstp, fh_copy(&resp->fh, &argp->fh), NULL,

				  argp->offset,

			   	  argp->vec, argp->vlen,

			   	  rqstp->rq_vec, argp->vlen,

				  &resp->count);



	if (nfserr) return nfserr;
@@ -185,7 +185,7 @@ nfsd_proc_write(struct svc_rqst *rqstp, struct nfsd_writeargs *argp, 


	nfserr = nfsd_write(rqstp, fh_copy(&resp->fh, &argp->fh), NULL,

				   argp->offset,

				   argp->vec, argp->vlen,

				   rqstp->rq_vec, argp->vlen,

				   argp->len,

				   &stable);

	return nfsd_return_attrs(nfserr, resp);

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