| Message ID | 1ecb1ec37388c616335dba37b42b4a7676df6c1e.1491115954.git.fthain@telegraphics.com.au (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
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?
Hi Martin, I must have missed that one - where was it posted to? Cheers, Michael 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,
> I must have missed that one - where was it posted to?
Usual bat channel:
https://patchwork.kernel.org/patch/9658369/
Martin, looks good to me, so: Reviewed-By: Michael Schmitz <schmitzmic@gmail.com> 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 <schmitzmic@gmail.com> Applied to 4.12/scsi-queue. Thank you!
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);
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> --- drivers/scsi/mac_esp.c | 33 +++++++++++++++++++++++---------- 1 file changed, 23 insertions(+), 10 deletions(-)