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Subject[PATCH net-next v7 5/9] xen-netback: Remove old TX grant copy definitons and fix indentations
Date
These became obsolete with grant mapping. I've left intentionally the
indentations in this way, to improve readability of previous patches.

NOTE: if bisect brought you here, you should apply the series up until
"xen-netback: Timeout packets in RX path", otherwise Windows guests can't work
properly and malicious guests can block other guests by not releasing their sent
packets.

Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com>
---
v2:
- move the indentation fixup patch here

v4:
- indentation fixes

diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 8719500..8e59b14 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -48,37 +48,8 @@
typedef unsigned int pending_ring_idx_t;
#define INVALID_PENDING_RING_IDX (~0U)

-/* For the head field in pending_tx_info: it is used to indicate
- * whether this tx info is the head of one or more coalesced requests.
- *
- * When head != INVALID_PENDING_RING_IDX, it means the start of a new
- * tx requests queue and the end of previous queue.
- *
- * An example sequence of head fields (I = INVALID_PENDING_RING_IDX):
- *
- * ...|0 I I I|5 I|9 I I I|...
- * -->|<-INUSE----------------
- *
- * After consuming the first slot(s) we have:
- *
- * ...|V V V V|5 I|9 I I I|...
- * -----FREE->|<-INUSE--------
- *
- * where V stands for "valid pending ring index". Any number other
- * than INVALID_PENDING_RING_IDX is OK. These entries are considered
- * free and can contain any number other than
- * INVALID_PENDING_RING_IDX. In practice we use 0.
- *
- * The in use non-INVALID_PENDING_RING_IDX (say 0, 5 and 9 in the
- * above example) number is the index into pending_tx_info and
- * mmap_pages arrays.
- */
struct pending_tx_info {
- struct xen_netif_tx_request req; /* coalesced tx request */
- pending_ring_idx_t head; /* head != INVALID_PENDING_RING_IDX
- * if it is head of one or more tx
- * reqs
- */
+ struct xen_netif_tx_request req; /* tx request */
/* Callback data for released SKBs. The callback is always
* xenvif_zerocopy_callback, desc contains the pending_idx, which is
* also an index in pending_tx_info array. It is initialized in
@@ -149,11 +120,6 @@ struct xenvif {
struct pending_tx_info pending_tx_info[MAX_PENDING_REQS];
grant_handle_t grant_tx_handle[MAX_PENDING_REQS];

- /* Coalescing tx requests before copying makes number of grant
- * copy ops greater or equal to number of slots required. In
- * worst case a tx request consumes 2 gnttab_copy.
- */
- struct gnttab_copy tx_copy_ops[2*MAX_PENDING_REQS];
struct gnttab_map_grant_ref tx_map_ops[MAX_PENDING_REQS];
struct gnttab_unmap_grant_ref tx_unmap_ops[MAX_PENDING_REQS];
/* passed to gnttab_[un]map_refs with pages under (un)mapping */
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 763d49a..bd09028 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -62,16 +62,6 @@ module_param(separate_tx_rx_irq, bool, 0644);
static unsigned int fatal_skb_slots = FATAL_SKB_SLOTS_DEFAULT;
module_param(fatal_skb_slots, uint, 0444);

-/*
- * If head != INVALID_PENDING_RING_IDX, it means this tx request is head of
- * one or more merged tx requests, otherwise it is the continuation of
- * previous tx request.
- */
-static inline int pending_tx_is_head(struct xenvif *vif, RING_IDX idx)
-{
- return vif->pending_tx_info[idx].head != INVALID_PENDING_RING_IDX;
-}
-
static void xenvif_idx_release(struct xenvif *vif, u16 pending_idx,
u8 status);

@@ -790,19 +780,6 @@ static int xenvif_count_requests(struct xenvif *vif,
return slots;
}

-static struct page *xenvif_alloc_page(struct xenvif *vif,
- u16 pending_idx)
-{
- struct page *page;
-
- page = alloc_page(GFP_ATOMIC|__GFP_COLD);
- if (!page)
- return NULL;
- vif->mmap_pages[pending_idx] = page;
-
- return page;
-}
-

struct xenvif_tx_cb {
u16 pending_idx;
@@ -832,13 +809,9 @@ static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif *vif,
struct skb_shared_info *shinfo = skb_shinfo(skb);
skb_frag_t *frags = shinfo->frags;
u16 pending_idx = XENVIF_TX_CB(skb)->pending_idx;
- u16 head_idx = 0;
- int slot, start;
- struct page *page;
- pending_ring_idx_t index, start_idx = 0;
- uint16_t dst_offset;
+ int start;
+ pending_ring_idx_t index;
unsigned int nr_slots;
- struct pending_tx_info *first = NULL;

/* At this point shinfo->nr_frags is in fact the number of
* slots, which can be as large as XEN_NETBK_LEGACY_SLOTS_MAX.
@@ -850,8 +823,8 @@ static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif *vif,

for (shinfo->nr_frags = start; shinfo->nr_frags < nr_slots;
shinfo->nr_frags++, txp++, gop++) {
- index = pending_index(vif->pending_cons++);
- pending_idx = vif->pending_ring[index];
+ index = pending_index(vif->pending_cons++);
+ pending_idx = vif->pending_ring[index];
xenvif_tx_create_gop(vif, pending_idx, txp, gop);
frag_set_pending_idx(&frags[shinfo->nr_frags], pending_idx);
}
@@ -859,18 +832,6 @@ static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif *vif,
BUG_ON(shinfo->nr_frags > MAX_SKB_FRAGS);

return gop;
-err:
- /* Unwind, freeing all pages and sending error responses. */
- while (shinfo->nr_frags-- > start) {
- xenvif_idx_release(vif,
- frag_get_pending_idx(&frags[shinfo->nr_frags]),
- XEN_NETIF_RSP_ERROR);
- }
- /* The head too, if necessary. */
- if (start)
- xenvif_idx_release(vif, pending_idx, XEN_NETIF_RSP_ERROR);
-
- return NULL;
}

static inline void xenvif_grant_handle_set(struct xenvif *vif,
@@ -910,7 +871,6 @@ static int xenvif_tx_check_gop(struct xenvif *vif,
struct pending_tx_info *tx_info;
int nr_frags = shinfo->nr_frags;
int i, err, start;
- u16 peek; /* peek into next tx request */

/* Check status of header. */
err = gop->status;
@@ -924,14 +884,12 @@ static int xenvif_tx_check_gop(struct xenvif *vif,

for (i = start; i < nr_frags; i++) {
int j, newerr;
- pending_ring_idx_t head;

pending_idx = frag_get_pending_idx(&shinfo->frags[i]);
tx_info = &vif->pending_tx_info[pending_idx];
- head = tx_info->head;

/* Check error status: if okay then remember grant handle. */
- newerr = (++gop)->status;
+ newerr = (++gop)->status;

if (likely(!newerr)) {
xenvif_grant_handle_set(vif, pending_idx , gop->handle);
@@ -1136,7 +1094,6 @@ static unsigned xenvif_tx_build_gops(struct xenvif *vif, int budget)
(skb_queue_len(&vif->tx_queue) < budget)) {
struct xen_netif_tx_request txreq;
struct xen_netif_tx_request txfrags[XEN_NETBK_LEGACY_SLOTS_MAX];
- struct page *page;
struct xen_netif_extra_info extras[XEN_NETIF_EXTRA_TYPE_MAX-1];
u16 pending_idx;
RING_IDX idx;
@@ -1507,18 +1464,17 @@ static void xenvif_idx_release(struct xenvif *vif, u16 pending_idx,
{
struct pending_tx_info *pending_tx_info;
pending_ring_idx_t index;
- u16 peek; /* peek into next tx request */
unsigned long flags;

- pending_tx_info = &vif->pending_tx_info[pending_idx];
- spin_lock_irqsave(&vif->response_lock, flags);
- make_tx_response(vif, &pending_tx_info->req, status);
- index = pending_index(vif->pending_prod);
- vif->pending_ring[index] = pending_idx;
- /* TX shouldn't use the index before we give it back here */
- mb();
- vif->pending_prod++;
- spin_unlock_irqrestore(&vif->response_lock, flags);
+ pending_tx_info = &vif->pending_tx_info[pending_idx];
+ spin_lock_irqsave(&vif->response_lock, flags);
+ make_tx_response(vif, &pending_tx_info->req, status);
+ index = pending_index(vif->pending_prod);
+ vif->pending_ring[index] = pending_idx;
+ /* TX shouldn't use the index before we give it back here */
+ mb();
+ vif->pending_prod++;
+ spin_unlock_irqrestore(&vif->response_lock, flags);
}



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