mirror of https://gitee.com/openkylin/linux.git
b43: Rewrite DMA Tx status handling sanity checks
This rewrites the error handling policies in the TX status handler. It tries to be error-tolerant as in "try hard to not crash the machine". It won't recover from errors (that are bugs in the firmware or driver), because that's impossible. However, it will return a more or less useful error message and bail out. It also tries hard to use rate-limited messages to not flood the syslog in case of a failure. Signed-off-by: Michael Buesch <mb@bu3sch.de> Signed-off-by: John W. Linville <linville@tuxdriver.com>
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8c35024aa6
commit
07681e211d
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@ -874,7 +874,7 @@ static void free_all_descbuffers(struct b43_dmaring *ring)
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for (i = 0; i < ring->nr_slots; i++) {
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desc = ring->ops->idx2desc(ring, i, &meta);
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if (!meta->skb) {
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if (!meta->skb || b43_dma_ptr_is_poisoned(meta->skb)) {
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B43_WARN_ON(!ring->tx);
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continue;
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}
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@ -926,7 +926,7 @@ struct b43_dmaring *b43_setup_dmaring(struct b43_wldev *dev,
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enum b43_dmatype type)
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{
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struct b43_dmaring *ring;
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int err;
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int i, err;
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dma_addr_t dma_test;
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ring = kzalloc(sizeof(*ring), GFP_KERNEL);
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@ -941,6 +941,8 @@ struct b43_dmaring *b43_setup_dmaring(struct b43_wldev *dev,
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GFP_KERNEL);
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if (!ring->meta)
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goto err_kfree_ring;
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for (i = 0; i < ring->nr_slots; i++)
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ring->meta->skb = B43_DMA_PTR_POISON;
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ring->type = type;
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ring->dev = dev;
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@ -1251,11 +1253,13 @@ struct b43_dmaring *parse_cookie(struct b43_wldev *dev, u16 cookie, int *slot)
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case 0x5000:
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ring = dma->tx_ring_mcast;
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break;
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default:
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B43_WARN_ON(1);
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}
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*slot = (cookie & 0x0FFF);
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B43_WARN_ON(!(ring && *slot >= 0 && *slot < ring->nr_slots));
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if (unlikely(!ring || *slot < 0 || *slot >= ring->nr_slots)) {
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b43dbg(dev->wl, "TX-status contains "
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"invalid cookie: 0x%04X\n", cookie);
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return NULL;
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}
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return ring;
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}
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@ -1494,19 +1498,40 @@ void b43_dma_handle_txstatus(struct b43_wldev *dev,
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struct b43_dmaring *ring;
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struct b43_dmadesc_generic *desc;
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struct b43_dmadesc_meta *meta;
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int slot;
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int slot, firstused;
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bool frame_succeed;
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ring = parse_cookie(dev, status->cookie, &slot);
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if (unlikely(!ring))
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return;
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B43_WARN_ON(!ring->tx);
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/* Sanity check: TX packets are processed in-order on one ring.
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* Check if the slot deduced from the cookie really is the first
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* used slot. */
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firstused = ring->current_slot - ring->used_slots + 1;
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if (firstused < 0)
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firstused = ring->nr_slots + firstused;
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if (unlikely(slot != firstused)) {
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/* This possibly is a firmware bug and will result in
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* malfunction, memory leaks and/or stall of DMA functionality. */
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b43dbg(dev->wl, "Out of order TX status report on DMA ring %d. "
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"Expected %d, but got %d\n",
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ring->index, firstused, slot);
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return;
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}
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ops = ring->ops;
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while (1) {
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B43_WARN_ON(!(slot >= 0 && slot < ring->nr_slots));
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B43_WARN_ON(slot < 0 || slot >= ring->nr_slots);
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desc = ops->idx2desc(ring, slot, &meta);
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if (b43_dma_ptr_is_poisoned(meta->skb)) {
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b43dbg(dev->wl, "Poisoned TX slot %d (first=%d) "
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"on ring %d\n",
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slot, firstused, ring->index);
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break;
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}
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if (meta->skb) {
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struct b43_private_tx_info *priv_info =
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b43_get_priv_tx_info(IEEE80211_SKB_CB(meta->skb));
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@ -1522,7 +1547,14 @@ void b43_dma_handle_txstatus(struct b43_wldev *dev,
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if (meta->is_last_fragment) {
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struct ieee80211_tx_info *info;
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BUG_ON(!meta->skb);
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if (unlikely(!meta->skb)) {
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/* This is a scatter-gather fragment of a frame, so
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* the skb pointer must not be NULL. */
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b43dbg(dev->wl, "TX status unexpected NULL skb "
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"at slot %d (first=%d) on ring %d\n",
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slot, firstused, ring->index);
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break;
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}
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info = IEEE80211_SKB_CB(meta->skb);
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@ -1540,20 +1572,29 @@ void b43_dma_handle_txstatus(struct b43_wldev *dev,
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#endif /* DEBUG */
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ieee80211_tx_status(dev->wl->hw, meta->skb);
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/* skb is freed by ieee80211_tx_status() */
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meta->skb = NULL;
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/* skb will be freed by ieee80211_tx_status().
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* Poison our pointer. */
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meta->skb = B43_DMA_PTR_POISON;
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} else {
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/* No need to call free_descriptor_buffer here, as
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* this is only the txhdr, which is not allocated.
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*/
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B43_WARN_ON(meta->skb);
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if (unlikely(meta->skb)) {
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b43dbg(dev->wl, "TX status unexpected non-NULL skb "
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"at slot %d (first=%d) on ring %d\n",
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slot, firstused, ring->index);
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break;
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}
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}
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/* Everything unmapped and free'd. So it's not used anymore. */
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ring->used_slots--;
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if (meta->is_last_fragment)
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if (meta->is_last_fragment) {
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/* This is the last scatter-gather
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* fragment of the frame. We are done. */
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break;
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}
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slot = next_slot(ring, slot);
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}
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if (ring->stopped) {
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@ -1,7 +1,7 @@
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#ifndef B43_DMA_H_
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#define B43_DMA_H_
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#include <linux/ieee80211.h>
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#include <linux/err.h>
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#include "b43.h"
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@ -164,6 +164,10 @@ struct b43_dmadesc_generic {
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#define B43_RXRING_SLOTS 64
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#define B43_DMA0_RX_BUFFERSIZE IEEE80211_MAX_FRAME_LEN
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/* Pointer poison */
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#define B43_DMA_PTR_POISON ((void *)ERR_PTR(-ENOMEM))
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#define b43_dma_ptr_is_poisoned(ptr) (unlikely((ptr) == B43_DMA_PTR_POISON))
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struct sk_buff;
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struct b43_private;
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