[CASSINI]: dont touch page_count
Nick Piggin [Wed, 18 Jan 2006 22:05:16 +0000 (14:05 -0800)]
Remove page refcount manipulations from cassini driver by using
another field in struct page. Needed for lockless pagecache.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/cassini.c

index dde631f..6e295fc 100644 (file)
@@ -335,6 +335,30 @@ static inline void cas_mask_intr(struct cas *cp)
                cas_disable_irq(cp, i);
 }
 
+static inline void cas_buffer_init(cas_page_t *cp)
+{
+       struct page *page = cp->buffer;
+       atomic_set((atomic_t *)&page->lru.next, 1);
+}
+
+static inline int cas_buffer_count(cas_page_t *cp)
+{
+       struct page *page = cp->buffer;
+       return atomic_read((atomic_t *)&page->lru.next);
+}
+
+static inline void cas_buffer_inc(cas_page_t *cp)
+{
+       struct page *page = cp->buffer;
+       atomic_inc((atomic_t *)&page->lru.next);
+}
+
+static inline void cas_buffer_dec(cas_page_t *cp)
+{
+       struct page *page = cp->buffer;
+       atomic_dec((atomic_t *)&page->lru.next);
+}
+
 static void cas_enable_irq(struct cas *cp, const int ring)
 {
        if (ring == 0) { /* all but TX_DONE */
@@ -472,6 +496,7 @@ static int cas_page_free(struct cas *cp, cas_page_t *page)
 {
        pci_unmap_page(cp->pdev, page->dma_addr, cp->page_size, 
                       PCI_DMA_FROMDEVICE);
+       cas_buffer_dec(page);
        __free_pages(page->buffer, cp->page_order);
        kfree(page);
        return 0;
@@ -501,6 +526,7 @@ static cas_page_t *cas_page_alloc(struct cas *cp, const gfp_t flags)
        page->buffer = alloc_pages(flags, cp->page_order);
        if (!page->buffer)
                goto page_err;
+       cas_buffer_init(page);
        page->dma_addr = pci_map_page(cp->pdev, page->buffer, 0,
                                      cp->page_size, PCI_DMA_FROMDEVICE);
        return page;
@@ -579,7 +605,7 @@ static void cas_spare_recover(struct cas *cp, const gfp_t flags)
        list_for_each_safe(elem, tmp, &list) {
                cas_page_t *page = list_entry(elem, cas_page_t, list);
 
-               if (page_count(page->buffer) > 1) 
+               if (cas_buffer_count(page) > 1)
                        continue;
 
                list_del(elem);
@@ -1347,7 +1373,7 @@ static inline cas_page_t *cas_page_spare(struct cas *cp, const int index)
        cas_page_t *page = cp->rx_pages[1][index];
        cas_page_t *new;
 
-       if (page_count(page->buffer) == 1)
+       if (cas_buffer_count(page) == 1)
                return page;
 
        new = cas_page_dequeue(cp);
@@ -1367,7 +1393,7 @@ static cas_page_t *cas_page_swap(struct cas *cp, const int ring,
        cas_page_t **page1 = cp->rx_pages[1];
 
        /* swap if buffer is in use */
-       if (page_count(page0[index]->buffer) > 1) {
+       if (cas_buffer_count(page0[index]) > 1) {
                cas_page_t *new = cas_page_spare(cp, index);
                if (new) {
                        page1[index] = page0[index];
@@ -2039,6 +2065,7 @@ static int cas_rx_process_pkt(struct cas *cp, struct cas_rx_comp *rxc,
                skb->len      += hlen - swivel;
 
                get_page(page->buffer);
+               cas_buffer_inc(page);
                frag->page = page->buffer;
                frag->page_offset = off;
                frag->size = hlen - swivel;
@@ -2063,6 +2090,7 @@ static int cas_rx_process_pkt(struct cas *cp, struct cas_rx_comp *rxc,
                        frag++;
 
                        get_page(page->buffer);
+                       cas_buffer_inc(page);
                        frag->page = page->buffer;
                        frag->page_offset = 0;
                        frag->size = hlen;
@@ -2225,7 +2253,7 @@ static int cas_post_rxds_ringN(struct cas *cp, int ring, int num)
        released = 0;
        while (entry != last) {
                /* make a new buffer if it's still in use */
-               if (page_count(page[entry]->buffer) > 1) {
+               if (cas_buffer_count(page[entry]) > 1) {
                        cas_page_t *new = cas_page_dequeue(cp);
                        if (!new) {
                                /* let the timer know that we need to