diff options
| author | Finn Thain <fthain@telegraphics.com.au> | 2017-04-02 10:08:05 +0300 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2017-04-25 20:00:59 +0300 |
| commit | 4da2b1eb230ba4ad19b58984dc52e05b1073df5f (patch) | |
| tree | c6bcd3f383f9e766bd2fd65b741d424e27433553 /drivers/scsi/mac_esp.c | |
| parent | 62d57f20ff6d9715c5d7605c5b6b1a2e6f4fbbd8 (diff) | |
| download | linux-4da2b1eb230ba4ad19b58984dc52e05b1073df5f.tar.xz | |
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>
Diffstat (limited to 'drivers/scsi/mac_esp.c')
| -rw-r--r-- | drivers/scsi/mac_esp.c | 33 |
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); |