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fd19881492
While there is no issued with the number of descriptors in a virtio indirect descriptor, it's a guest's choice as to whether indirect descriptors are used. For the case where they aren't, the virtio block ring size is still 64 which is less than the now reported max_segs of 67. This results in an assertion in recent Linux guests even though it was benign since they were using indirect descs. The intertwined relationship between virtio ring size, max seg size and blockif queue size will be addressed in an upcoming commit, at which point the max descriptors will again be bumped up to 67.
71 lines
2.8 KiB
C
71 lines
2.8 KiB
C
/*-
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* Copyright (c) 2013 Peter Grehan <grehan@freebsd.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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/*
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* The block API to be used by bhyve block-device emulations. The routines
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* are thread safe, with no assumptions about the context of the completion
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* callback - it may occur in the caller's context, or asynchronously in
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* another thread.
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*/
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#ifndef _BLOCK_IF_H_
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#define _BLOCK_IF_H_
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#include <sys/uio.h>
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#include <sys/unistd.h>
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#define BLOCKIF_IOV_MAX 33 /* not practical to be IOV_MAX */
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struct blockif_req {
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struct iovec br_iov[BLOCKIF_IOV_MAX];
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int br_iovcnt;
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off_t br_offset;
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ssize_t br_resid;
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void (*br_callback)(struct blockif_req *req, int err);
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void *br_param;
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};
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struct blockif_ctxt;
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struct blockif_ctxt *blockif_open(const char *optstr, const char *ident);
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off_t blockif_size(struct blockif_ctxt *bc);
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void blockif_chs(struct blockif_ctxt *bc, uint16_t *c, uint8_t *h,
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uint8_t *s);
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int blockif_sectsz(struct blockif_ctxt *bc);
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void blockif_psectsz(struct blockif_ctxt *bc, int *size, int *off);
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int blockif_queuesz(struct blockif_ctxt *bc);
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int blockif_is_ro(struct blockif_ctxt *bc);
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int blockif_candelete(struct blockif_ctxt *bc);
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int blockif_read(struct blockif_ctxt *bc, struct blockif_req *breq);
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int blockif_write(struct blockif_ctxt *bc, struct blockif_req *breq);
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int blockif_flush(struct blockif_ctxt *bc, struct blockif_req *breq);
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int blockif_delete(struct blockif_ctxt *bc, struct blockif_req *breq);
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int blockif_cancel(struct blockif_ctxt *bc, struct blockif_req *breq);
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int blockif_close(struct blockif_ctxt *bc);
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#endif /* _BLOCK_IF_H_ */
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