[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v4] xenbus_client: extend interface to suppurt multi-page ring
On Sat, Nov 9, 2013 at 4:30 AM, Wei Liu <wei.liu2@xxxxxxxxxx> wrote: > @@ -357,17 +365,39 @@ static void xenbus_switch_fatal(struct xenbus_device > *dev, int depth, int err, > /** > * xenbus_grant_ring > * @dev: xenbus device > - * @ring_mfn: mfn of ring to grant > - > - * Grant access to the given @ring_mfn to the peer of the given device. > Return > - * 0 on success, or -errno on error. On error, the device will switch to > + * @vaddr: starting virtual address of the ring > + * @nr_pages: number of pages to be granted > + * @grefs: grant reference array to be filled in > + * > + * Grant access to the given @vaddr to the peer of the given device. > + * Then fill in @grefs with grant references. Return 0 on success, or > + * -errno on error. On error, the device will switch to > * XenbusStateClosing, and the error will be saved in the store. > */ > -int xenbus_grant_ring(struct xenbus_device *dev, unsigned long ring_mfn) > +int xenbus_grant_ring(struct xenbus_device *dev, void *vaddr, > + unsigned int nr_pages, grant_ref_t *grefs) > { > - int err = gnttab_grant_foreign_access(dev->otherend_id, ring_mfn, 0); > - if (err < 0) > - xenbus_dev_fatal(dev, err, "granting access to ring page"); > + int err; > + int i; > + > + for (i = 0; i < nr_pages; i++) { > + unsigned long addr = (unsigned long)vaddr + > + (PAGE_SIZE * i); > + err = gnttab_grant_foreign_access(dev->otherend_id, > + virt_to_mfn(addr), 0); > + if (err < 0) { > + xenbus_dev_fatal(dev, err, > + "granting access to ring page"); > + goto fail; > + } > + grefs[i] = err; > + } > + > + return 0; > + > +fail: > + for (; i >= 0; i--) There's an off-by-one here, causing gnttab_end_foreign_access_ref to be called on the first uninitialized (at least in this function) gref. > + gnttab_end_foreign_access_ref(grefs[i], 0); > return err; > } > EXPORT_SYMBOL_GPL(xenbus_grant_ring); > @@ -448,62 +478,131 @@ EXPORT_SYMBOL_GPL(xenbus_free_evtchn); > /** > * xenbus_map_ring_valloc > * @dev: xenbus device > - * @gnt_ref: grant reference > + * @gnt_refs: grant reference array > + * @nr_grefs: number of grant references > * @vaddr: pointer to address to be filled out by mapping > * > - * Based on Rusty Russell's skeleton driver's map_page. > - * Map a page of memory into this domain from another domain's grant table. > - * xenbus_map_ring_valloc allocates a page of virtual address space, maps the > - * page to that address, and sets *vaddr to that address. > - * Returns 0 on success, and GNTST_* (see > xen/include/interface/grant_table.h) > - * or -ENOMEM on error. If an error is returned, device will switch to > + * Map @nr_grefs pages of memory into this domain from another > + * domain's grant table. xenbus_map_ring_valloc allocates @nr_grefs > + * pages of virtual address space, maps the pages to that address, and > + * sets *vaddr to that address. Returns 0 on success, and GNTST_* > + * (see xen/include/interface/grant_table.h) or -ENOMEM / -EINVAL on > + * error. If an error is returned, device will switch to > * XenbusStateClosing and the error message will be saved in XenStore. > */ > -int xenbus_map_ring_valloc(struct xenbus_device *dev, int gnt_ref, void > **vaddr) > +int xenbus_map_ring_valloc(struct xenbus_device *dev, grant_ref_t *gnt_refs, > + unsigned int nr_grefs, void **vaddr) > { > - return ring_ops->map(dev, gnt_ref, vaddr); > + return ring_ops->map(dev, gnt_refs, nr_grefs, vaddr); > } > EXPORT_SYMBOL_GPL(xenbus_map_ring_valloc); > > +/* N.B. sizeof(phys_addr_t) doesn't always equal to sizeof(unsigned > + * long), e.g. 32-on-64. Caller is responsible for preparing the > + * right array to feed into this function */ > +static int __xenbus_map_ring(struct xenbus_device *dev, > + grant_ref_t *gnt_refs, > + unsigned int nr_grefs, > + grant_handle_t *handles, > + phys_addr_t *addrs, > + unsigned int flags, > + bool *leaked) > +{ > + struct gnttab_map_grant_ref map[XENBUS_MAX_RING_PAGES]; > + struct gnttab_unmap_grant_ref unmap[XENBUS_MAX_RING_PAGES]; > + int i, j; > + int err = GNTST_okay; > + > + if (nr_grefs > XENBUS_MAX_RING_PAGES) > + return -EINVAL; > + > + for (i = 0; i < nr_grefs; i++) { > + memset(&map[i], 0, sizeof(map[i])); > + gnttab_set_map_op(&map[i], addrs[i], flags, gnt_refs[i], > + dev->otherend_id); > + handles[i] = INVALID_GRANT_HANDLE; > + } > + > + gnttab_batch_map(map, i); > + > + for (i = 0; i < nr_grefs; i++) { > + if (map[i].status != GNTST_okay) { > + err = map[i].status; > + xenbus_dev_fatal(dev, map[i].status, > + "mapping in shared page %d from > domain %d", > + gnt_refs[i], dev->otherend_id); > + goto fail; > + } else > + handles[i] = map[i].handle; > + } > + > + return GNTST_okay; > + > + fail: > + for (i = j = 0; i < nr_grefs; i++) { > + memset(&unmap[i], 0, sizeof(unmap[i])); I think you mean unmap[j], not unmap[i] (both times)? If so, you might as well only do this in the following if block, not out here unconditionally. > + if (handles[i] != INVALID_GRANT_HANDLE) { > + gnttab_set_unmap_op(&unmap[j], (phys_addr_t)addrs[i], > + GNTMAP_host_map, handles[i]); > + j++; > + } > + } > + > + if (HYPERVISOR_grant_table_op(GNTTABOP_unmap_grant_ref, unmap, j)) > + BUG(); > + > + *leaked = false; > + for (i = 0; i < j; i++) { > + if (unmap[i].status != GNTST_okay) { > + *leaked = true; > + break; > + } > + } > + > + return err; > + Extra blank line? - Matthew > +} > + _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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