[PATCH 2/5] Char: isicom, fix probe race

Jiri Slaby
2006-12-16T01:33:22Z

isicom, fix probe race

Fix two race conditions in the probe function with mutex.

Signed-off-by: Jiri Slaby <jirislaby@gmail.com>

---
commit e7087b32ad4b5ee1240fa7f9ba46a9b4566fe424
tree 28bc5ad2a47c03e1b7a09fce22afbe7000955e97
parent f2d37e8d3de070f8cda48a454f7b991d29b310be
author Jiri Slaby <jirislaby@gmail.com> Fri, 15 Dec 2006 21:08:11 +0059
committer Jiri Slaby <jirislaby@gmail.com> Fri, 15 Dec 2006 21:08:11 +0059

drivers/char/isicom.c | 26 ++++++++++++++++----------
1 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/drivers/char/isicom.c b/drivers/char/isicom.c
index 836e967..5d2c345 100644
--- a/drivers/char/isicom.c
+++ b/drivers/char/isicom.c
@@ -1732,22 +1732,25 @@ end:
/*
* Insmod can set static symbols so keep these static
*/
-static int card;
+static unsigned int card_count;

static int __devinit isicom_probe(struct pci_dev *pdev,
const struct pci_device_id *ent)
{
+ static DEFINE_MUTEX(probe_lock);
unsigned int ioaddr, signature, index;
int retval = -EPERM;
- u8 pciirq;
struct isi_board *board = NULL;

- if (card >= BOARD_COUNT)
+ mutex_lock(&probe_lock);
+ if (card_count >= BOARD_COUNT) {
+ mutex_unlock(&probe_lock);
goto err;
+ }
+ card_count++;

ioaddr = pci_resource_start(pdev, 3);
/* i.e at offset 0x1c in the PCI configuration register space. */
- pciirq = pdev->irq;
dev_info(&pdev->dev, "ISI PCI Card(Device ID 0x%x)\n", ent->device);

/* allot the first empty slot in the array */
@@ -1759,8 +1762,9 @@ static int __devinit isicom_probe(struct pci_dev *pdev,

board->index = index;
board->base = ioaddr;
- board->irq = pciirq;
- card++;
+ board->irq = pdev->irq;
+
+ mutex_unlock(&probe_lock);

pci_set_drvdata(pdev, board);

@@ -1770,7 +1774,7 @@ static int __devinit isicom_probe(struct pci_dev *pdev,
"will be disabled.\n", board->base, board->base + 15,
index + 1);
retval = -EBUSY;
- goto err;
+ goto err_dec;
}

retval = request_irq(board->irq, isicom_interrupt,
@@ -1799,8 +1803,10 @@ errunri:
free_irq(board->irq, board);
errunrr:
pci_release_region(pdev, 3);
-err:
+err_dec:
+ card_count--;
board->base = 0;
+err:
return retval;
}

@@ -1814,6 +1820,8 @@ static void __devexit isicom_remove(struct pci_dev *pdev)

free_irq(board->irq, board);
pci_release_region(pdev, 3);
+ card_count--;
+ board->base = 0;
}

static int __init isicom_init(void)
@@ -1821,8 +1829,6 @@ static int __init isicom_init(void)
int retval, idx, channel;
struct isi_port *port;

- card = 0;
-
for(idx = 0; idx < BOARD_COUNT; idx++) {
port = &isi_ports[idx * 16];
isi_card[idx].ports = port;