[PATCH] Fix locking in gianfar

This patch fixes several bugs in the gianfar driver, including a major one
where spinlocks were horribly broken:

* Split gianfar locks into two types: TX and RX
* Made it so gfar_start() now clears RHALT
* Fixed a bug where calling gfar_start_xmit() with interrupts off would
corrupt the interrupt state
* Fixed a bug where a frame could potentially arrive, and never be handled
(if no more frames arrived
* Fixed a bug where the rx_work_limit would never be observed by the rx
completion code
* Fixed a bug where the interrupt handlers were not actually protected by
their spinlocks

Signed-off-by: Andy Fleming <afleming@freescale.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 46 insertions, 21 deletions

diff --git a/drivers/net/gianfar.h b/drivers/net/gianfar.h
index d37d5401be6e..127c98cf3336 100644
--- a/drivers/net/gianfar.h
+++ b/drivers/net/gianfar.h
@@ -656,43 +656,62 @@ struct gfar {
  * the buffer descriptor determines the actual condition.
  */
 struct gfar_private {
-        /* pointers to arrays of skbuffs for tx and rx */
+        /* Fields controlled by TX lock */
+        spinlock_t txlock;
+
+        /* Pointer to the array of skbuffs */
         struct sk_buff ** tx_skbuff;
-        struct sk_buff ** rx_skbuff;
 
-        /* indices pointing to the next free sbk in skb arrays */
+        /* next free skb in the array */
         u16 skb_curtx;
-        u16 skb_currx;
 
-        /* index of the first skb which hasn't been transmitted
-         * yet. */
+        /* First skb in line to be transmitted */
         u16 skb_dirtytx;
 
         /* Configuration info for the coalescing features */
         unsigned char txcoalescing;
         unsigned short txcount;
         unsigned short txtime;
+
+        /* Buffer descriptor pointers */
+        struct txbd8 *tx_bd_base;       /* First tx buffer descriptor */
+        struct txbd8 *cur_tx;           /* Next free ring entry */
+        struct txbd8 *dirty_tx;         /* First buffer in line
+                                           to be transmitted */
+        unsigned int tx_ring_size;
+
+        /* RX Locked fields */
+        spinlock_t rxlock;
+
+        /* skb array and index */
+        struct sk_buff ** rx_skbuff;
+        u16 skb_currx;
+
+        /* RX Coalescing values */
         unsigned char rxcoalescing;
         unsigned short rxcount;
         unsigned short rxtime;
 
-        /* GFAR addresses */
-        struct rxbd8 *rx_bd_base;       /* Base addresses of Rx and Tx Buffers */
-        struct txbd8 *tx_bd_base;
+        struct rxbd8 *rx_bd_base;       /* First Rx buffers */
         struct rxbd8 *cur_rx;           /* Next free rx ring entry */
-        struct txbd8 *cur_tx;           /* Next free ring entry */
-        struct txbd8 *dirty_tx;         /* The Ring entry to be freed. */
-        struct gfar __iomem *regs;      /* Pointer to the GFAR memory mapped Registers */
-        u32 __iomem *hash_regs[16];
-        int hash_width;
-        struct net_device_stats stats; /* linux network statistics */
-        struct gfar_extra_stats extra_stats;
-        spinlock_t lock;
+
+        /* RX parameters */
+        unsigned int rx_ring_size;
         unsigned int rx_buffer_size;
         unsigned int rx_stash_size;
         unsigned int rx_stash_index;
-        unsigned int tx_ring_size;
-        unsigned int rx_ring_size;
+
+        struct vlan_group *vlgrp;
+
+        /* Unprotected fields */
+        /* Pointer to the GFAR memory mapped Registers */
+        struct gfar __iomem *regs;
+
+        /* Hash registers and their width */
+        u32 __iomem *hash_regs[16];
+        int hash_width;
+
+        /* global parameters */
         unsigned int fifo_threshold;
         unsigned int fifo_starve;
         unsigned int fifo_starve_off;
@@ -702,13 +721,15 @@ struct gfar_private {
                 extended_hash:1,
                 bd_stash_en:1;
         unsigned short padding;
-        struct vlan_group *vlgrp;
-        /* Info structure initialized by board setup code */
+
         unsigned int interruptTransmit;
         unsigned int interruptReceive;
         unsigned int interruptError;
+
+        /* info structure initialized by platform code */
         struct gianfar_platform_data *einfo;
 
+        /* PHY stuff */
         struct phy_device *phydev;
         struct mii_bus *mii_bus;
         int oldspeed;
@@ -716,6 +737,10 @@ struct gfar_private {
         int oldlink;
 
         uint32_t msg_enable;
+
+        /* Network Statistics */
+        struct net_device_stats stats;
+        struct gfar_extra_stats extra_stats;
 };
 
 static inline u32 gfar_read(volatile unsigned __iomem *addr)