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[01/10] iwlwifi: read the Rx write pointer only once

Message ID 1355176158-24675-1-git-send-email-johannes@sipsolutions.net (mailing list archive)
State Not Applicable, archived
Headers show

Commit Message

Johannes Berg Dec. 10, 2012, 9:49 p.m. UTC 
From: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

The FH (DMA engine) tells the driver the index of the last
ready (closed) Rx buffer. This data is in closed_rb_num.
If we read this data several times we may get inconsistencies
between the code and the debug prints which can make it
harder to debug issues here.

Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 drivers/net/wireless/iwlwifi/pcie/rx.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
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Patch

diff --git a/drivers/net/wireless/iwlwifi/pcie/rx.c b/drivers/net/wireless/iwlwifi/pcie/rx.c
index c81b978..787b9ca 100644
--- a/drivers/net/wireless/iwlwifi/pcie/rx.c
+++ b/drivers/net/wireless/iwlwifi/pcie/rx.c
@@ -698,7 +698,7 @@  static void iwl_pcie_rx_handle(struct iwl_trans *trans)
 
 	/* uCode's read index (stored in shared DRAM) indicates the last Rx
 	 * buffer that the driver may process (last buffer filled by ucode). */
-	r = le16_to_cpu(rxq->rb_stts->closed_rb_num) &  0x0FFF;
+	r = le16_to_cpu(ACCESS_ONCE(rxq->rb_stts->closed_rb_num)) & 0x0FFF;
 	i = rxq->read;
 
 	/* Rx interrupt, but nothing sent from uCode */