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xen-netfront: fix resource leak in netfront
This patch removes grant transfer releasing code from netfront, and uses gnttab_end_foreign_access to end grant access since gnttab_end_foreign_access_ref may fail when the grant entry is currently used for reading or writing. * clean up grant transfer code kept from old netfront(2.6.18) which grants pages for access/map and transfer. But grant transfer is deprecated in current netfront, so remove corresponding release code for transfer. * fix resource leak, release grant access (through gnttab_end_foreign_access) and skb for tx/rx path, use get_page to ensure page is released when grant access is completed successfully. Xen-blkfront/xen-tpmfront/xen-pcifront also have similar issue, but patches for them will be created separately. V6: Correct subject line and commit message. V5: Remove unecessary change in xennet_end_access. V4: Revert put_page in gnttab_end_foreign_access, and keep netfront change in single patch. V3: Changes as suggestion from David Vrabel, ensure pages are not freed untill grant acess is ended. V2: Improve patch comments. Signed-off-by: Annie Li <annie.li@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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@ -117,6 +117,7 @@ struct netfront_info {
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} tx_skbs[NET_TX_RING_SIZE];
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grant_ref_t gref_tx_head;
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grant_ref_t grant_tx_ref[NET_TX_RING_SIZE];
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struct page *grant_tx_page[NET_TX_RING_SIZE];
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unsigned tx_skb_freelist;
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spinlock_t rx_lock ____cacheline_aligned_in_smp;
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@ -396,6 +397,7 @@ static void xennet_tx_buf_gc(struct net_device *dev)
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gnttab_release_grant_reference(
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&np->gref_tx_head, np->grant_tx_ref[id]);
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np->grant_tx_ref[id] = GRANT_INVALID_REF;
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np->grant_tx_page[id] = NULL;
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add_id_to_freelist(&np->tx_skb_freelist, np->tx_skbs, id);
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dev_kfree_skb_irq(skb);
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}
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@ -452,6 +454,7 @@ static void xennet_make_frags(struct sk_buff *skb, struct net_device *dev,
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gnttab_grant_foreign_access_ref(ref, np->xbdev->otherend_id,
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mfn, GNTMAP_readonly);
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np->grant_tx_page[id] = virt_to_page(data);
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tx->gref = np->grant_tx_ref[id] = ref;
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tx->offset = offset;
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tx->size = len;
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@ -497,6 +500,7 @@ static void xennet_make_frags(struct sk_buff *skb, struct net_device *dev,
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np->xbdev->otherend_id,
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mfn, GNTMAP_readonly);
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np->grant_tx_page[id] = page;
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tx->gref = np->grant_tx_ref[id] = ref;
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tx->offset = offset;
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tx->size = bytes;
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@ -596,6 +600,7 @@ static int xennet_start_xmit(struct sk_buff *skb, struct net_device *dev)
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mfn = virt_to_mfn(data);
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gnttab_grant_foreign_access_ref(
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ref, np->xbdev->otherend_id, mfn, GNTMAP_readonly);
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np->grant_tx_page[id] = virt_to_page(data);
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tx->gref = np->grant_tx_ref[id] = ref;
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tx->offset = offset;
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tx->size = len;
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@ -1085,10 +1090,11 @@ static void xennet_release_tx_bufs(struct netfront_info *np)
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continue;
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skb = np->tx_skbs[i].skb;
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gnttab_end_foreign_access_ref(np->grant_tx_ref[i],
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GNTMAP_readonly);
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gnttab_release_grant_reference(&np->gref_tx_head,
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np->grant_tx_ref[i]);
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get_page(np->grant_tx_page[i]);
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gnttab_end_foreign_access(np->grant_tx_ref[i],
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GNTMAP_readonly,
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(unsigned long)page_address(np->grant_tx_page[i]));
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np->grant_tx_page[i] = NULL;
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np->grant_tx_ref[i] = GRANT_INVALID_REF;
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add_id_to_freelist(&np->tx_skb_freelist, np->tx_skbs, i);
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dev_kfree_skb_irq(skb);
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@ -1097,78 +1103,35 @@ static void xennet_release_tx_bufs(struct netfront_info *np)
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static void xennet_release_rx_bufs(struct netfront_info *np)
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{
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struct mmu_update *mmu = np->rx_mmu;
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struct multicall_entry *mcl = np->rx_mcl;
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struct sk_buff_head free_list;
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struct sk_buff *skb;
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unsigned long mfn;
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int xfer = 0, noxfer = 0, unused = 0;
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int id, ref;
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dev_warn(&np->netdev->dev, "%s: fix me for copying receiver.\n",
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__func__);
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return;
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skb_queue_head_init(&free_list);
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spin_lock_bh(&np->rx_lock);
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for (id = 0; id < NET_RX_RING_SIZE; id++) {
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ref = np->grant_rx_ref[id];
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if (ref == GRANT_INVALID_REF) {
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unused++;
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continue;
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}
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struct sk_buff *skb;
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struct page *page;
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skb = np->rx_skbs[id];
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mfn = gnttab_end_foreign_transfer_ref(ref);
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gnttab_release_grant_reference(&np->gref_rx_head, ref);
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if (!skb)
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continue;
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ref = np->grant_rx_ref[id];
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if (ref == GRANT_INVALID_REF)
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continue;
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page = skb_frag_page(&skb_shinfo(skb)->frags[0]);
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/* gnttab_end_foreign_access() needs a page ref until
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* foreign access is ended (which may be deferred).
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*/
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get_page(page);
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gnttab_end_foreign_access(ref, 0,
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(unsigned long)page_address(page));
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np->grant_rx_ref[id] = GRANT_INVALID_REF;
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if (0 == mfn) {
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skb_shinfo(skb)->nr_frags = 0;
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dev_kfree_skb(skb);
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noxfer++;
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continue;
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}
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if (!xen_feature(XENFEAT_auto_translated_physmap)) {
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/* Remap the page. */
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const struct page *page =
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skb_frag_page(&skb_shinfo(skb)->frags[0]);
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unsigned long pfn = page_to_pfn(page);
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void *vaddr = page_address(page);
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MULTI_update_va_mapping(mcl, (unsigned long)vaddr,
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mfn_pte(mfn, PAGE_KERNEL),
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0);
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mcl++;
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mmu->ptr = ((u64)mfn << PAGE_SHIFT)
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| MMU_MACHPHYS_UPDATE;
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mmu->val = pfn;
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mmu++;
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set_phys_to_machine(pfn, mfn);
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}
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__skb_queue_tail(&free_list, skb);
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xfer++;
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kfree_skb(skb);
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}
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dev_info(&np->netdev->dev, "%s: %d xfer, %d noxfer, %d unused\n",
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__func__, xfer, noxfer, unused);
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if (xfer) {
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if (!xen_feature(XENFEAT_auto_translated_physmap)) {
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/* Do all the remapping work and M2P updates. */
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MULTI_mmu_update(mcl, np->rx_mmu, mmu - np->rx_mmu,
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NULL, DOMID_SELF);
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mcl++;
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HYPERVISOR_multicall(np->rx_mcl, mcl - np->rx_mcl);
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}
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}
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__skb_queue_purge(&free_list);
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spin_unlock_bh(&np->rx_lock);
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}
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@ -1339,6 +1302,7 @@ static struct net_device *xennet_create_dev(struct xenbus_device *dev)
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for (i = 0; i < NET_RX_RING_SIZE; i++) {
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np->rx_skbs[i] = NULL;
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np->grant_rx_ref[i] = GRANT_INVALID_REF;
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np->grant_tx_page[i] = NULL;
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}
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/* A grant for every tx ring slot */
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