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 <[email protected]>
---
drivers/scsi/mac_esp.c | 33 +++++++++++++++++++++++----------
1 file changed, 23 insertions(+), 10 deletions(-)
diff --git a/drivers/scsi/mac_esp.c b/drivers/scsi/mac_esp.c
index 14c0334..586efd1 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);
--
2.10.2
Finn,
> 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.
Ondrej/Michael: Mind reviewing this change?
--
Martin K. Petersen Oracle Linux Engineering
Martin,
looks good to me, so:
Reviewed-By: Michael Schmitz <[email protected]>
Am 25.04.2017 um 10:29 schrieb Martin K. Petersen:
>
> Finn,
>
>> 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.
>
> Ondrej/Michael: Mind reviewing this change?
>
Michael,
> looks good to me, so:
>
> Reviewed-By: Michael Schmitz <[email protected]>
Applied to 4.12/scsi-queue.
Thank you!
--
Martin K. Petersen Oracle Linux Engineering