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authorFinn Thain <fthain@telegraphics.com.au>2017-04-02 17:08:05 +1000
committerMartin K. Petersen <martin.petersen@oracle.com>2017-04-25 13:00:59 -0400
commit4da2b1eb230ba4ad19b58984dc52e05b1073df5f (patch)
treec6bcd3f383f9e766bd2fd65b741d424e27433553
parent62d57f20ff6d9715c5d7605c5b6b1a2e6f4fbbd8 (diff)
scsi: mac_esp: Replace bogus memory barrier with spinlock
Commit da244654c66e ("[SCSI] mac_esp: fix for quadras with two esp chips") added mac_scsi_esp_intr() to handle the IRQ lines from a pair of on-board ESP chips (a normal shared IRQ did not work). Proper mutual exclusion was missing from that patch. This patch fixes race conditions between comparison and assignment of esp_chips[] pointers. Signed-off-by: Finn Thain <fthain@telegraphics.com.au> Reviewed-by: Michael Schmitz <schmitzmic@gmail.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
-rw-r--r--drivers/scsi/mac_esp.c33
1 files changed, 23 insertions, 10 deletions
diff --git a/drivers/scsi/mac_esp.c b/drivers/scsi/mac_esp.c
index 14c0334f41e4..26c67c42985c 100644
--- a/drivers/scsi/mac_esp.c
+++ b/drivers/scsi/mac_esp.c
@@ -55,6 +55,7 @@ struct mac_esp_priv {
int error;
};
static struct esp *esp_chips[2];
+static DEFINE_SPINLOCK(esp_chips_lock);
#define MAC_ESP_GET_PRIV(esp) ((struct mac_esp_priv *) \
platform_get_drvdata((struct platform_device *) \
@@ -562,15 +563,18 @@ static int esp_mac_probe(struct platform_device *dev)
}
host->irq = IRQ_MAC_SCSI;
- esp_chips[dev->id] = esp;
- mb();
- if (esp_chips[!dev->id] == NULL) {
- err = request_irq(host->irq, mac_scsi_esp_intr, 0, "ESP", NULL);
- if (err < 0) {
- esp_chips[dev->id] = NULL;
- goto fail_free_priv;
- }
+
+ /* The request_irq() call is intended to succeed for the first device
+ * and fail for the second device.
+ */
+ err = request_irq(host->irq, mac_scsi_esp_intr, 0, "ESP", NULL);
+ spin_lock(&esp_chips_lock);
+ if (err < 0 && esp_chips[!dev->id] == NULL) {
+ spin_unlock(&esp_chips_lock);
+ goto fail_free_priv;
}
+ esp_chips[dev->id] = esp;
+ spin_unlock(&esp_chips_lock);
err = scsi_esp_register(esp, &dev->dev);
if (err)
@@ -579,8 +583,13 @@ static int esp_mac_probe(struct platform_device *dev)
return 0;
fail_free_irq:
- if (esp_chips[!dev->id] == NULL)
+ spin_lock(&esp_chips_lock);
+ esp_chips[dev->id] = NULL;
+ if (esp_chips[!dev->id] == NULL) {
+ spin_unlock(&esp_chips_lock);
free_irq(host->irq, esp);
+ } else
+ spin_unlock(&esp_chips_lock);
fail_free_priv:
kfree(mep);
fail_free_command_block:
@@ -599,9 +608,13 @@ static int esp_mac_remove(struct platform_device *dev)
scsi_esp_unregister(esp);
+ spin_lock(&esp_chips_lock);
esp_chips[dev->id] = NULL;
- if (!(esp_chips[0] || esp_chips[1]))
+ if (esp_chips[!dev->id] == NULL) {
+ spin_unlock(&esp_chips_lock);
free_irq(irq, NULL);
+ } else
+ spin_unlock(&esp_chips_lock);
kfree(mep);